US20020014632A1 - Group III nitride compound semiconductor light-emitting device - Google Patents

Group III nitride compound semiconductor light-emitting device Download PDF

Info

Publication number
US20020014632A1
US20020014632A1 US09/523,463 US52346300A US2002014632A1 US 20020014632 A1 US20020014632 A1 US 20020014632A1 US 52346300 A US52346300 A US 52346300A US 2002014632 A1 US2002014632 A1 US 2002014632A1
Authority
US
United States
Prior art keywords
layer
thick
light
type
type contact
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
US09/523,463
Other versions
US6452214B2 (en
Inventor
Naoki Kaneyama
Makoto Asai
Katsuhisa Sawazaki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyoda Gosei Co Ltd
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Assigned to TOYODA GOSEI CO., LTD. reassignment TOYODA GOSEI CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ASAI, MAKOTO, KANEYAMA, NAOKI, SAWAZAKI, KATSUHISA
Publication of US20020014632A1 publication Critical patent/US20020014632A1/en
Priority to US10/192,699 priority Critical patent/US6762070B2/en
Application granted granted Critical
Publication of US6452214B2 publication Critical patent/US6452214B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26Materials of the light emitting region
    • H01L33/30Materials of the light emitting region containing only elements of group III and group V of the periodic system
    • H01L33/32Materials of the light emitting region containing only elements of group III and group V of the periodic system containing nitrogen
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00Nanooptics, e.g. quantum optics or photonic crystals
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00Semiconductor lasers
    • H01S5/04Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
    • H01S5/042Electrical excitation ; Circuits therefor
    • H01S5/0421Electrical excitation ; Circuits therefor characterised by the semiconducting contacting layers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00Semiconductor lasers
    • H01S5/30Structure or shape of the active region; Materials used for the active region
    • H01S5/34Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
    • H01S5/343Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
    • H01S5/34333Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Definitions

  • the present invention relates to a group III nitride compound semiconductor light-emitting device having a light emission output of high light intensity.
  • a device of a double heterostructure for emitting green or blue light is known as a light-emitting device comprising layers of group III nitride compound semiconductors laminated on a substrate.
  • a light-emitting device with a p-type clad layer made of Al x Ga 1 ⁇ x N (0 ⁇ x ⁇ 1) is generally known.
  • a p-type contact layer was generally heretofore made of gallium nitride (GaN).
  • the present invention is designed to solve the aforementioned problem and an object thereof is to provide a light-emitting device of high light intensity by eliminating the disadvantage caused by the difference both in thermal expansion coefficient and in lattice constant between the aforementioned two layers.
  • a semiconductor light-emitting device comprising layers of group III nitride compound semiconductors laminated on a substrate, and a p-type clad layer of Al x Ga 1 ⁇ x N (0 ⁇ x ⁇ 1), is in that the device further comprises a p-type contact layer made of Al y Ga 1 ⁇ y N (0 ⁇ y ⁇ x) which is lower in the composition ratio of aluminum (Al) than the p-type clad layer.
  • the p-type contact layer is made of Al y Ga 1 ⁇ y N (0.1x ⁇ y ⁇ 0.7x). More preferably, the value of the composition ratio y of aluminum (Al) in the p-type contact layer is approximately in the range “0.4x ⁇ y ⁇ 0.5x”.
  • the p-type contact layer is made of Al y Ga 1 ⁇ y N (0.01 ⁇ y ⁇ 0.12). More preferably, the absolute value of the composition ratio y of aluminum (Al) in the p-type contact layer is approximately in the range “0.03 ⁇ y ⁇ 0.08”.
  • the thickness of the p-type contact layer is selected to be in a range of from 200 ⁇ to 1000 ⁇ both inclusively. More preferably, the thickness of the p-type contact layer is selected to be in a range of from 500 ⁇ to 800 ⁇ both inclusively.
  • the group III nitride compound semiconductors according to the present invention are represented by the general formula Al x Ga y In 1 ⁇ x ⁇ y N (0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x+y ⁇ 1), which may further contain group III elements such as boron (B) and thallium (Tl) and in which the nitrogen (N) may be partially replaced by phosphorus (P), arsenic (As), antimony (Sb) or bismuth (Bi).
  • group III elements such as boron (B) and thallium (Tl) and in which the nitrogen (N) may be partially replaced by phosphorus (P), arsenic (As), antimony (Sb) or bismuth (Bi).
  • each of layers such as a buffer layer, a barrier layer, a well layer, a clad layer, a contact layer, an intermediate layer, a cap layer, etc. in the group III nitride compound semiconductor light-emitting device may be made of quaternary, ternary or binary Al x Ga y In 1 ⁇ x ⁇ y N (0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x+y ⁇ 1), such as AlGaN, InGaN, or the like, of an optional crystal mixture ratio.
  • a metal nitride compound such as titanium nitride (TiN), hafnium nitride (HfN), or the like, or a metal oxide compound such as zinc oxide (ZnO), magnesium oxide (MgO), manganese oxide (MnO), or the like, other than the aforementioned group III nitride compound semiconductor may be used as the buffer layer.
  • a group II element such as beryllium (Be), zinc (Zn), or the like, other than magnesium (Mg) may be used as the p-type impurities.
  • the n-type semiconductor layer may be formed by doping the aforementioned group III nitride compound semiconductor with a group IV element such as silicon (Si), germanium (Ge), or the like, or with a group VI element.
  • group IV element such as silicon (Si), germanium (Ge), or the like, or with a group VI element.
  • silicon carbide (SiC), zinc oxide (ZnO), magnesium oxide (MgO), manganese oxide (MnO), or the like, other than sapphire may be used as the substrate for crystal growth.
  • the composition of the p-type contact layer becomes close to that of the p-type clad layer. Hence, the difference in crystal lattice constant between the two layers is reduced, so that the p-type contact layer of good quality can be grown. Hence, the intensity of light emitted from the light-emitting device is improved.
  • the difference in thermal expansion coefficient between the two layers is reduced as well. Hence, stress remaining in the epitaxial wafer is reduced, so that the intensity of emitted light is improved.
  • the value of the composition ratio y of aluminum (Al) is selected to be preferably approximately in the range “0.1x ⁇ y ⁇ 0.7x”, more preferably in the range “0.4x ⁇ y ⁇ 0.5x”. If the value of the composition ratio y in the p-type contact layer is too large, contact resistance between the positive electrode and the p-type contact layer increases, undesirably resulting in an increase in the drive voltage of the light-emitting device. If the value of the composition ratio y is too small, it is difficult to obtain the aforementioned operation and effect of the present invention because the composition of the p-type contact layer is not close to that of the p-type clad layer.
  • the absolute value of the composition ratio y of aluminum (Al) in the p-type contact layer is also selected to be preferably approximately in the range “0.01 ⁇ y ⁇ 0.12”, more preferably in the range “0.03 ⁇ y ⁇ 0.08”. More in detail, the group III nitride compound semiconductor light-emitting device exhibits the highest intensity of emitted light particularly when the absolute value of the composition ratio y is about 0.05.
  • the thickness of the p-type contact layer is preferably in a range of from 200 ⁇ to 1000 ⁇ both inclusively. More preferably, the thickness of the p-type contact layer is in a range of from 500 ⁇ to 800 ⁇ both inclusively. When the thickness of the p-type contact layer is in this range, the light emission output of the light-emitting device exhibits a large value. Further, the group III nitride compound semiconductor light-emitting device according to the present invention exhibits the highest intensity of emitted light particularly when the thickness of the p-type contact layer is about 600 ⁇ .
  • FIG. 1 is a typical sectional view of a wire bonding type group III nitride compound semiconductor light-emitting device 100 according to the present invention
  • FIG. 2 is a graph showing a correlation between the light emission output of the light-emitting device according to the present invention and the thickness of a p-type contact layer;
  • FIG. 3 is a typical sectional view of a flip chip type group III nitride compound semiconductor light-emitting device 200 according to the present invention.
  • FIG. 1 is a sectional view showing a wire bonding type semiconductor light-emitting device 100 according to the present invention.
  • a buffer layer 102 of aluminum nitride (AlN) about 200 ⁇ thick is provided on a sapphire substrate 101 .
  • An intermediate layer 104 of non-doped In 0.03 Ga 0.97 N about 2000 ⁇ thick is formed on the high carrier density N + layer 103 .
  • An n-type clad layer 105 of GaN about 150 ⁇ thick is further laminated the intermediate layer 104 .
  • An MQW active layer 160 of a multilayer quantum well (MQW) structure which is formed by alternately laminating well layers 161 of Ga 0.8 In 0.2 N about 30 ⁇ thick each and barrier layers 162 of GaN about 70 ⁇ thick each, is further formed on the n-type clad layer 105 . That is, three well layers 161 and two barrier layers 162 are laminated alternately to thereby form an MQW structure which has a film thickness of about 230 ⁇ and which is composed of five layers in total with two cycles.
  • a cap layer 107 of GaN about 140 ⁇ thick and a p-type clad layer 108 of p-type Al 0.12 Ga 0.88 N about 200 ⁇ thick are formed successively on the MQW active layer 160 .
  • a p-type contact layer 109 of p-type Al 0.05 Ga 0.95 N about 600 ⁇ thick is further formed on the p-type clad layer 108 .
  • a light-transmissible thin-film positive electrode 110 is formed on the p-type contact layer 109 by metal evaporation whereas a negative electrode 140 is formed on the N + layer 103 .
  • the light-transmissible thin-film positive electrode 110 is composed of a thin-film positive electrode first layer 111 of cobalt (Co) about 15 ⁇ thick joined to the p-type contact layer 109 , and a thin-film positive electrode second layer 112 of gold (Au) about 60 ⁇ thick joined to the Co.
  • a thick-film positive electrode 120 is formed by successively laminating a thick-film electrode first layer 121 of vanadium (V) about 175 ⁇ thick, a thick-film electrode second layer 122 of gold (Au) about 15000 ⁇ thick and a thick-film electrode third layer 123 of aluminum (Al) about 100 ⁇ thick on the light-transmissible thin-film positive electrode 110 .
  • the negative electrode 140 of a multilayer structure is formed by successively laminating a vanadium (V) layer 141 about 175 ⁇ thick and an aluminum (Al) layer 142 about 1.8 ⁇ m thick on a partly exposed portion of the high carrier density N + layer 103 .
  • a protective film 130 constituted by an SiO 2 film is formed as the uppermost portion.
  • a reflection metal layer 150 of aluminum about 5000 ⁇ thick is formed as the opposite lowermost portion on the bottom surface of the sapphire substrate 101 by metal evaporation.
  • the aforementioned light-emitting device 100 was produced by vapor phase growth according to a metal organic vapor phase epitaxy method (MOVPE method).
  • the gasses used were ammonia (NH 3 ), carrier gas (H 2 , N 2 ), trimethylgallium (Ga(CH 3 ) 3 ) (hereinafter referred to as “TMG”), trimethylaluminum (Al(CH 3 ) 3 ) (hereinafter referred to as “TMA”), trimethylindium (In(CH 3 ) 3 ) (hereinafter referred to as “TMI”), silane (SiH 4 ), and cyclopentadienylmagnesium (Mg(C 5 H 5 ) 2 ) (hereinafter referred to as “CP 2 Mg”).
  • NH 3 ammonia
  • carrier gas H 2 , N 2
  • TMG trimethylgallium
  • Al(CH 3 ) 3 ) hereinafter referred to as “TMA”
  • TMI trimethylin
  • a single-crystal sapphire substrate 101 having a face a cleaned by an organic cleaning process as a main face was attached to a susceptor placed in a reaction chamber of an MOVPE apparatus. Then, the substrate 101 was baked at a temperature of 1150° C. while H 2 was introduced into the reaction chamber under normal atmospheric pressure.
  • a buffer layer 102 of AlN about 200 ⁇ thick was formed by decreasing the temperature of the substrate 101 to 400° C. and by supplying H 2 , NH 3 and TMA.
  • a high carrier density N + layer 103 which was made of GaN doped with silicon (Si) and which had a film thickness of about 4.0 ⁇ m and an electron density of 2 ⁇ 10 18 /cm 3 , was formed by increasing the temperature of the substrate 101 to 1150° C. and by supplying H 2 , NH 3 , TMG, and silane.
  • an intermediate layer 104 of In 0.03 Ga 0.97 N about 2000 ⁇ thick was formed by decreasing the temperature of the substrate 101 to 850° C. and by supplying either N 2 or H 2 , NH 3 , TMG and TMI.
  • an n-type clad layer 105 of GaN about 150 ⁇ thick was formed by keeping the temperature of the substrate 101 at 850° C. and by supplying either N 2 or H 2 , NH 3 and TMG.
  • a well layer 161 of Ga 0.8 In 0.2 N about 30 ⁇ thick was formed by supplying either N 2 or H 2 , NH 3 , TMG and TMI.
  • a barrier layer 162 of GaN about 70 ⁇ thick was formed by supplying either N 2 or H 2 , NH 3 and TMG.
  • a well layer 161 , a barrier layer 162 and a well layer 161 were further formed successively in the same condition as described above to thereby form an MQW active layer 160 about 230 ⁇ thick with two cycles in total.
  • a cap layer 107 of GaN about 140 ⁇ thick was further formed by supplying either N 2 or H 2 , NH 3 and TMG.
  • a p-type clad layer 108 which was made of p-type Al 0.12 Ga 0.88 N doped with magnesium (Mg) and which was about 200 ⁇ thick, was formed by keeping the temperature of the substrate 101 at 1150° C. and by supplying either N 2 or H 2 , NH 3 , TMG, TMA and CP 2 Mg.
  • a p-type contact layer 109 which was made of p-type Al 0.05 Ga 0.95 N doped with magnesium (Mg) and which was about 600 ⁇ thick, was formed by keeping the temperature of the substrate 101 at 1100° C. and by supplying either N 2 or H 2 , NH 3 , TMG, TMA and CP 2 Mg.
  • an etching mask was formed on the p-type contact layer 109 .
  • the non-masked portion of the p-type contact layer 109 , the p-type clad layer 108 , the MQW active layer 160 , the intermediate layer 104 and a part of the high carrier density N + layer 103 were etched with a chlorine-containing gas by reactive ion etching to thereby expose a surface of the N + layer 103 .
  • a negative electrode 140 to joined to the N + layer 103 and a light-transmissible thin-film positive electrode 110 to be joined to the p-type contact layer 109 were formed by the following procedure.
  • a thin-film positive electrode first layer 111 of Co about 15 ⁇ thick was formed on a surface evenly and a thin-film positive electrode second layer 112 of Au about 60 ⁇ thick was further formed on the thin-film positive electrode first layer 111 of Co by an evaporation apparatus.
  • a photo resist was applied and a window was formed in a predetermined region on the exposed surface of the N + layer 103 by photolithography. After evacuation to a high vacuum of the order of 10 ⁇ 4 Pa or less, a vanadium (V) layer 141 about 175 ⁇ thick and an aluminum (Al) layer 142 about 1.8 ⁇ m thick were formed successively by evaporation. Then, the photo resist was removed. As a result, the negative electrode 140 was formed on the exposed surface of the N + layer 103 .
  • V vanadium
  • Al aluminum
  • a heating process for reducing contact resistance between the p-type contact layer 109 and the light-transmissible thin-film positive electrode 110 was carried out. That is, the atmosphere for the sample was evacuated by a vacuum pump and an O 2 gas was supplied to thereby set a pressure of 10 Pa. In this condition, heating was performed for about 4 minutes to keep the atmospheric temperature at about 570° C.
  • a photo resist was applied evenly onto the light-transmissible thin-film positive electrode 110 and a window was formed in the thin-film positive electrode 120-forming portion of the photo resist. Then, a vanadium (V) layer 121 about 175 ⁇ thick, a gold (Au) layer 122 about 15000 ⁇ thick and an aluminum (Al) layer 123 about 100 ⁇ thick were formed on the light-transmissible thin-film positive electrode 110 successively by evaporation. Thus, the thick-film positive electrode 120 was formed by a lift-off method in the same manner as in the step (4).
  • a protective film 130 of SiO 2 was formed evenly on the upward exposed uppermost layer by electron beam evaporation, and a window was formed in each of portions of the protective film 130 on the thick-film positive electrode 120 and the negative electrode 140 by wet etching through the application of a photo resist and a photolithography process, so that the positive and negative electrodes 120 and 140 were exposed externally and the windows had their areas approximately equal to each other.
  • the light-emitting device 100 was formed.
  • the following expressions (1) and (2) hold for the p-type clad layer 108 of Al x Ga 1 ⁇ x N (0 ⁇ x ⁇ 1) and the p-type contact layer 109 of Al y Ga 1 ⁇ y N (0 ⁇ y ⁇ x) in the light-emitting device 100 .
  • the composition of the p-type contact layer was made relatively close to the composition of the p-type clad layer. Hence, the difference in crystal lattice constant between the two layers was reduced, so that the p-type contact layer of good quality was able to be grown. Hence, the intensity of light emitted from the light-emitting device was improved.
  • Another reason for improvement in the emitted light intensity of the light-emitting device 100 according to the present invention compared with the background art was that stress remaining in the light-emitting device was also reduced because the difference in thermal expansion coefficient between the two layers was relatively reduced.
  • the value of the composition ratio y of aluminum (Al) in the p-type contact layer 109 may be selected to be preferably approximately in the range “0.1x ⁇ y ⁇ 0.7x”, more preferably approximately in the range “0.4x ⁇ y ⁇ 0.5x”. If the value of the composition ratio y in the p-type contact layer is too large, contact resistance between the positive electrode and the p-type contact layer increases, undesirably resulting in increase in the drive voltage of the light-emitting device. If the value of the composition ratio y is contrariwise too small, it is difficult to obtain the aforementioned operation and effect because the composition of the p-type contact layer is not made close to the composition of the p-type clad layer.
  • the light-emitting device 100 in the first embodiment exhibits high light intensity because these conditions are satisfied sufficiently.
  • the absolute value of the composition ratio y of aluminum (Al) in the p-type contact layer 109 is also selected to be preferably approximately in the range “0.01 ⁇ y ⁇ 0.12”, more preferably approximately in the range “0.03 ⁇ y ⁇ 0.08”.
  • FIG. 2 is a graph showing a correlation between the light emission output of the light-emitting device 100 according to the present invention and the thickness of the p-type contact layer 109 .
  • the thickness of the p-type contact layer is selected to be preferably in a range of from 200 ⁇ to 1000 ⁇ both inclusively, more preferably in a range of from 500 ⁇ to 800 ⁇ both inclusively.
  • the light emission output of the light-emitting device exhibits a large value when the thickness of the p-type contact layer is in this range.
  • the original function of the p-type contact layer as a p-type low-resistance gallium nitride film containing a dopant for providing acceptors becomes insufficient to obtain a high light emission output if the p-type contact layer is too thin.
  • the p-type contact layer 109 is formed or when a heating process such as annealing, or the like, is carried out after the formation of the p-type contact layer 109 , solid solution may occur between the p-type contact layer 109 and the p-type clad layer 108 so that aluminum (Al) in the p-type clad layer 108 is eluted into the p-type contact layer 109 .
  • the p-type contact layer 109 is too thin, not only is it impossible that the value of the composition ratio y of aluminum (Al) in the p-type contact layer 109 is set to be in a desired range but also the light emission output of the light-emitting device varies largely.
  • the p-type contact layer 109 is contrariwise too thick, strong stress is imposed on the p-type clad layer 108 and layers below the p-type clad layer 108 because the thermal expansion coefficient of the p-type contact layer 109 is different from that of the p-type clad layer 108 . If the p-type contact layer 109 is too thick, it is also difficult to form the p-type contact layer 109 as a desired good-quality crystal structure because dislocation due to lattice mismatching caused by the difference between crystal lattice constants occurs easily in the p-type contact layer 109 .
  • the p-type contact layer 109 is too thick, because both reduction in the intensity of emitted light and increase in individual variation of the intensity of light emitted from the light-emitting devices are brought by these actions.
  • the light-emitting device 100 in the first embodiment can exhibit high light intensity because the thickness (600 ⁇ ) of the p-type contact layer 109 satisfies the aforementioned requirement sufficiently.
  • FIG. 3 is a typical sectional view showing a flip chip type semiconductor light-emitting device 200 according to the present invention.
  • a buffer layer 102 of aluminum nitride (AlN) about 200 ⁇ thick is provided on a sapphire substrate 101 .
  • An intermediate layer 104 of non-doped In 0.03 Ga 0.97 N about 1800 ⁇ thick is further formed on the N + layer 103 .
  • An n-type clad layer 105 and an MQW active layer 160 which is composed of GaN layers and Ga 0.8 In 0.2 N layers, are further formed on the intermediate layer 104 successively in the same manner as in the light-emitting device 100 according to the first embodiment.
  • a p-type contact layer 109 of Mg-doped Al 0.05 Ga 0.95 N about 600 ⁇ thick is further formed on the p-type clad layer 108 .
  • a multilayer thick-film electrode 220 is formed on the p-type contact layer 109 by metal evaporation whereas a negative electrode 240 is formed on the N + layer 103 .
  • the multilayer thick-film electrode 220 has a three-layered structure consisting of a first metal layer 221 joined to the p-type contact layer 109 , a second metal layer 222 formed on an upper face of the first metal layer 221 , and a third metal layer 223 formed on an upper face of the second metal layer 222 .
  • the first metal layer 221 is a metal layer of rhodium (Rh) or platinum (Pt) about 0.3 ⁇ m thick joined to the p-type contact layer 109 .
  • the second metal layer 222 is a metal layer of gold (Au) about 1.2 ⁇ m thick.
  • the third metal layer 223 is a metal layer of titanium (Ti) about 30 ⁇ thick.
  • the negative electrode 240 of a two-layered structure is formed by successively laminating a vanadium (V) layer 241 about 175 ⁇ thick and an aluminum (Al) layer 242 about 1.8 ⁇ m thick on the partly exposed portion of the high carrier density N + layer 103 .
  • a protective film 230 constituted by an SiO 2 film is formed between the multilayer thick-film positive electrode 220 and the negative electrode 240 which are formed as described above.
  • the protective layer 230 covers, from the N + layer 103 exposed for forming the negative electrode 240 , a side face of the MQW active layer 160 , a side face of the p-type clad layer 108 and a side face of the p-type contact layer 109 and a part of the upper face of the p-type contact layer 109 , which are exposed by etching, and further covers a side face of the first metal layer 221 , a side face of the second metal layer 222 and a part of the upper face of the third metal layer 223 .
  • the third metal layer 223 -covering portion of the protective film 230 constituted by an SiO 2 film is 0.5 ⁇ m thick.
  • a three-layered structure consisting of a first metal layer of rhodium (Rh) or platinum (Pt), a second metal layer of gold (Au), and a third metal layer of titanium (Ti) is applied to the multilayer thick-film positive electrode 220 in the flip chip type semiconductor light-emitting device 200 .
  • the semiconductor light-emitting device 200 is configured in the aforementioned manner, a semiconductor light-emitting device of higher light intensity than the background-art device can be achieved like the light-emitting device 100 .
  • the device exhibits relatively high light intensity when the thickness of the p-type clad layer 108 is in a range of from 100 ⁇ to 500 ⁇ . More preferably, the thickness of the p-type clad layer 108 is in an optimum range of from 180 ⁇ to 360 ⁇ . When the thickness is in the optimum range, the highest light emission output can be obtained.
  • the device exhibits relatively high light intensity when the thickness of the p-type clad layer 108 is in a range of from 70 ⁇ to 390 ⁇ . More preferably, the thickness of the p-type clad layer 108 is in an optimum range of from 90 ⁇ to 300 ⁇ . When the thickness is in the optimum range, the highest light emission output can be obtained.
  • the composition ratio x of aluminum (Al) in the p-type clad layer 108 made of Al x Ga 1 ⁇ x N is preferably approximately in a range of from 0.10 to 0.14, more preferably in a range of from 0.12 to 0.13. If x is smaller than 0.10, the light emission output is lowered because it is difficult to confine carriers in the active layer. If x is larger than 0.14, the light emission output is also lowered because stress applied to the active layer increases in accordance with the difference between lattice constants of crystals.
  • the number of cycles in the MQW active layer 160 in each of the light-emitting devices 100 and 200 is two, the number of cycles is not particularly limited. That is, the present invention can be applied also to a group III nitride compound semiconductor light-emitting device having an active layer with any number of cycles or any structure.
  • the active layer 160 may have a SQW (single quantum well) structure.
  • each of group III nitride compound semiconductor layers, inclusive of the buffer layer, the intermediate layer and the cap layer, for constituting the light-emitting device according to the present invention may be made of quaternary, ternary or binary Al x Ga y In 1 ⁇ x ⁇ y N (0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x+y ⁇ 1) of an optional crystal mixture ratio.
  • a metal nitride compound such as titanium nitride (TiN), hafnium nitride (HfN), or the like, or a metal oxide compound such as zinc oxide (ZnO), magnesium oxide (MgO), manganese oxide (MnO), or the like, other than the aforementioned group III nitride compound semiconductor may be used as the buffer layer.
  • a group II element such as beryllium (Be), zinc (Zn), or the like, other than magnesium (Mg) may be used as the p-type impurities.
  • an activating process such as electron beam irradiation, annealing, or the like, may be further carried out.
  • the high carrier density N + layer 103 is made of gallium nitride (GaN) doped with silicon (Si)
  • these n-type semiconductor layers may be formed by doping the aforementioned group III nitride compound semiconductor with a group IV element such as silicon (Si), germanium (Ge), or the like, or with a group VI element.
  • silicon carbide (SiC), zinc oxide (ZnO), magnesium oxide (Mgo), manganese oxide (MnO), or the like, other than sapphire may be used as the substrate for crystal growth.
  • the present invention can be applied to light-receiving devices as well as light-emitting devices.

Abstract

A cap layer of GaN about 140 Å thick and a p-type clad layer of Mg-doped p-type AlxGa1−xN (x=0.12) about 200 Å thick are formed successively on an MQW active layer about 230 Å thick. A p-type contact layer of Mg-doped p-type AlyGa1−yN (y=0.05) about 600 Å thick is further formed thereon. These composition ratios x and y are selected to satisfy the expression “0.03 ≦0.3x≦y≦0.5x≦0.08”, so that the composition of the p-type contact layer becomes close to the composition of the p-type clad layer.

Description

    BACKGROUND OF THE INVENTION
  • 1. Field of the Invention [0001]
  • The present invention relates to a group III nitride compound semiconductor light-emitting device having a light emission output of high light intensity. [0002]
  • The present application is based on Japanese Patent Application No. Hei. 11-090718, which is incorporated herein by reference. [0003]
  • 2. Description of the Related Art [0004]
  • A device of a double heterostructure for emitting green or blue light is known as a light-emitting device comprising layers of group III nitride compound semiconductors laminated on a substrate. For example, a light-emitting device with a p-type clad layer made of Al[0005] xGa1−xN (0<x<1) is generally known. In this type light-emitting devices, a p-type contact layer was generally heretofore made of gallium nitride (GaN).
  • When a p-type contact layer made of gallium nitride (GaN) was grown on a p-type clad layer made of Al[0006] xGa1−xN (0<x<1), the difference both in layer thermal expansion coefficient and in crystal lattice constant between the p-type clad layer and the p-type contact layer increased as the value of the composition ratio x increased.
  • If the difference in crystal lattice constant between the two layers became large, the p-type contact layer was hardly grown as a layer of good quality. This caused reduction in intensity of emitted light. [0007]
  • On the other hand, if the difference in thermal expansion coefficient between the two layers became large, distortion due to the difference in thermal expansion coefficient was caused in an epitaxial wafer when the temperature was decreased from a high temperature to a room temperature after crystal growth. As a result, stress remained in the epitaxial wafer, so that this caused reduction in intensity of emitted light. [0008]
  • SUMMARY OF THE INVENTION
  • The present invention is designed to solve the aforementioned problem and an object thereof is to provide a light-emitting device of high light intensity by eliminating the disadvantage caused by the difference both in thermal expansion coefficient and in lattice constant between the aforementioned two layers. [0009]
  • The following means are effective for solving the problem. [0010]
  • That is, as a first means, there is provided a semiconductor light-emitting device comprising layers of group III nitride compound semiconductors laminated on a substrate, and a p-type clad layer of Al[0011] xGa1−xN (0<x<1), is in that the device further comprises a p-type contact layer made of AlyGa1−yN (0<y<x) which is lower in the composition ratio of aluminum (Al) than the p-type clad layer.
  • As a second means, preferably, in the first means, the p-type contact layer is made of Al[0012] yGa1−yN (0.1x≦y≦0.7x). More preferably, the value of the composition ratio y of aluminum (Al) in the p-type contact layer is approximately in the range “0.4x≦y≦0.5x”.
  • As a third means, preferably, in first means, the p-type contact layer is made of Al[0013] yGa1−yN (0.01≦y≦0.12). More preferably, the absolute value of the composition ratio y of aluminum (Al) in the p-type contact layer is approximately in the range “0.03≦y≦0.08”.
  • As a fourth means, preferably, in any one of the first, second and third means, the thickness of the p-type contact layer is selected to be in a range of from 200 Å to 1000 Å both inclusively. More preferably, the thickness of the p-type contact layer is selected to be in a range of from 500 Å to 800 Å both inclusively. [0014]
  • The aforementioned problem can be solved by the above means. [0015]
  • Incidentally, the group III nitride compound semiconductors according to the present invention are represented by the general formula Al[0016] xGayIn1−x−yN (0≦x≦1, 0≦y≦1, 0≦x+y≦1), which may further contain group III elements such as boron (B) and thallium (Tl) and in which the nitrogen (N) may be partially replaced by phosphorus (P), arsenic (As), antimony (Sb) or bismuth (Bi).
  • Accordingly, each of layers such as a buffer layer, a barrier layer, a well layer, a clad layer, a contact layer, an intermediate layer, a cap layer, etc. in the group III nitride compound semiconductor light-emitting device may be made of quaternary, ternary or binary Al[0017] xGayIn1−x−yN (0≦x≦1, 0≦y≦1, 0≦x+y≦1), such as AlGaN, InGaN, or the like, of an optional crystal mixture ratio.
  • Further, a metal nitride compound such as titanium nitride (TiN), hafnium nitride (HfN), or the like, or a metal oxide compound such as zinc oxide (ZnO), magnesium oxide (MgO), manganese oxide (MnO), or the like, other than the aforementioned group III nitride compound semiconductor may be used as the buffer layer. [0018]
  • Further, a group II element such as beryllium (Be), zinc (Zn), or the like, other than magnesium (Mg) may be used as the p-type impurities. [0019]
  • Further, the n-type semiconductor layer may be formed by doping the aforementioned group III nitride compound semiconductor with a group IV element such as silicon (Si), germanium (Ge), or the like, or with a group VI element. [0020]
  • Further, silicon carbide (SiC), zinc oxide (ZnO), magnesium oxide (MgO), manganese oxide (MnO), or the like, other than sapphire may be used as the substrate for crystal growth. [0021]
  • According to the means of the present invention, the composition of the p-type contact layer becomes close to that of the p-type clad layer. Hence, the difference in crystal lattice constant between the two layers is reduced, so that the p-type contact layer of good quality can be grown. Hence, the intensity of light emitted from the light-emitting device is improved. [0022]
  • According to the means of the present invention, the difference in thermal expansion coefficient between the two layers is reduced as well. Hence, stress remaining in the epitaxial wafer is reduced, so that the intensity of emitted light is improved. [0023]
  • When a p-type contact layer of Al[0024] yGa1−yN (0<y<x), which is lower in the composition ratio of aluminum (Al) than a p-type clad layer of AlxGa1−x(0<x≦1), is grown on the p-type clad layer, the value of the composition ratio y of aluminum (Al) is selected to be preferably approximately in the range “0.1x≦y≦0.7x”, more preferably in the range “0.4x≦y≦0.5x”. If the value of the composition ratio y in the p-type contact layer is too large, contact resistance between the positive electrode and the p-type contact layer increases, undesirably resulting in an increase in the drive voltage of the light-emitting device. If the value of the composition ratio y is too small, it is difficult to obtain the aforementioned operation and effect of the present invention because the composition of the p-type contact layer is not close to that of the p-type clad layer.
  • For the same reason as described above, the absolute value of the composition ratio y of aluminum (Al) in the p-type contact layer is also selected to be preferably approximately in the range “0.01≦y≦0.12”, more preferably in the range “0.03≦y≦0.08”. More in detail, the group III nitride compound semiconductor light-emitting device exhibits the highest intensity of emitted light particularly when the absolute value of the composition ratio y is about 0.05. [0025]
  • Though will be described later in detail, there is a strong correlation between the light emission output of the, light-emitting device and the thickness of the p-type contact layer as shown in FIG. 2. Hence, the thickness of the p-type contact layer is preferably in a range of from 200 Å to 1000 Å both inclusively. More preferably, the thickness of the p-type contact layer is in a range of from 500 Å to 800 Å both inclusively. When the thickness of the p-type contact layer is in this range, the light emission output of the light-emitting device exhibits a large value. Further, the group III nitride compound semiconductor light-emitting device according to the present invention exhibits the highest intensity of emitted light particularly when the thickness of the p-type contact layer is about 600 Å. [0026]
  • Features and advantages of the invention will be evident from the following detailed description of the preferred embodiments described in conjunction with the attached drawings.[0027]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • In the accompanying drawings: [0028]
  • FIG. 1 is a typical sectional view of a wire bonding type group III nitride compound semiconductor light-[0029] emitting device 100 according to the present invention;
  • FIG. 2 is a graph showing a correlation between the light emission output of the light-emitting device according to the present invention and the thickness of a p-type contact layer; and [0030]
  • FIG. 3 is a typical sectional view of a flip chip type group III nitride compound semiconductor light-[0031] emitting device 200 according to the present invention.
  • DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • The present invention will be described hereunder on the basis of specific embodiments thereof. [0032]
  • (First Embodiment) [0033]
  • FIG. 1 is a sectional view showing a wire bonding type semiconductor light-[0034] emitting device 100 according to the present invention. A buffer layer 102 of aluminum nitride (AlN) about 200 Å thick is provided on a sapphire substrate 101. An n+ layer 103 of a high carrier density, which is made of GaN doped with silicon (Si) and which is about 4.0 μm thick, is formed on the buffer layer 102.
  • An [0035] intermediate layer 104 of non-doped In0.03Ga0.97N about 2000 Å thick is formed on the high carrier density N+ layer 103.
  • An n-[0036] type clad layer 105 of GaN about 150 Å thick is further laminated the intermediate layer 104. An MQW active layer 160 of a multilayer quantum well (MQW) structure, which is formed by alternately laminating well layers 161 of Ga0.8In0.2N about 30 Å thick each and barrier layers 162 of GaN about 70 Å thick each, is further formed on the n-type clad layer 105. That is, three well layers 161 and two barrier layers 162 are laminated alternately to thereby form an MQW structure which has a film thickness of about 230 Å and which is composed of five layers in total with two cycles.
  • A [0037] cap layer 107 of GaN about 140 Å thick and a p-type clad layer 108 of p-type Al0.12Ga0.88N about 200 Å thick are formed successively on the MQW active layer 160. A p-type contact layer 109 of p-type Al0.05Ga0.95N about 600 Å thick is further formed on the p-type clad layer 108.
  • Further, a light-transmissible thin-film [0038] positive electrode 110 is formed on the p-type contact layer 109 by metal evaporation whereas a negative electrode 140 is formed on the N+ layer 103. The light-transmissible thin-film positive electrode 110 is composed of a thin-film positive electrode first layer 111 of cobalt (Co) about 15 Å thick joined to the p-type contact layer 109, and a thin-film positive electrode second layer 112 of gold (Au) about 60 Å thick joined to the Co.
  • A thick-film [0039] positive electrode 120 is formed by successively laminating a thick-film electrode first layer 121 of vanadium (V) about 175 Å thick, a thick-film electrode second layer 122 of gold (Au) about 15000 Å thick and a thick-film electrode third layer 123 of aluminum (Al) about 100 Å thick on the light-transmissible thin-film positive electrode 110. The negative electrode 140 of a multilayer structure is formed by successively laminating a vanadium (V) layer 141 about 175 Å thick and an aluminum (Al) layer 142 about 1.8 μm thick on a partly exposed portion of the high carrier density N+ layer 103.
  • Further, a [0040] protective film 130 constituted by an SiO2 film is formed as the uppermost portion. Further, a reflection metal layer 150 of aluminum about 5000 Å thick is formed as the opposite lowermost portion on the bottom surface of the sapphire substrate 101 by metal evaporation.
  • A method for producing the light-emitting [0041] device 100 will be described below.
  • The aforementioned light-emitting [0042] device 100 was produced by vapor phase growth according to a metal organic vapor phase epitaxy method (MOVPE method). The gasses used were ammonia (NH3), carrier gas (H2, N2), trimethylgallium (Ga(CH3)3) (hereinafter referred to as “TMG”), trimethylaluminum (Al(CH3)3) (hereinafter referred to as “TMA”), trimethylindium (In(CH3)3) (hereinafter referred to as “TMI”), silane (SiH4), and cyclopentadienylmagnesium (Mg(C5H5)2) (hereinafter referred to as “CP2Mg”).
  • First, a single-[0043] crystal sapphire substrate 101 having a face a cleaned by an organic cleaning process as a main face was attached to a susceptor placed in a reaction chamber of an MOVPE apparatus. Then, the substrate 101 was baked at a temperature of 1150° C. while H2 was introduced into the reaction chamber under normal atmospheric pressure.
  • Then, a [0044] buffer layer 102 of AlN about 200 Å thick was formed by decreasing the temperature of the substrate 101 to 400° C. and by supplying H2, NH3 and TMA.
  • Then, a high carrier density N[0045] + layer 103, which was made of GaN doped with silicon (Si) and which had a film thickness of about 4.0 μm and an electron density of 2×1018/cm3, was formed by increasing the temperature of the substrate 101 to 1150° C. and by supplying H2, NH3, TMG, and silane.
  • Then, an [0046] intermediate layer 104 of In0.03Ga0.97N about 2000 Å thick was formed by decreasing the temperature of the substrate 101 to 850° C. and by supplying either N2 or H2, NH3, TMG and TMI.
  • After the [0047] intermediate layer 104 was formed, an n-type clad layer 105 of GaN about 150 Å thick was formed by keeping the temperature of the substrate 101 at 850° C. and by supplying either N2 or H2, NH3 and TMG.
  • Then, a [0048] well layer 161 of Ga0.8In0.2N about 30 Å thick was formed by supplying either N2 or H2, NH3, TMG and TMI. Then, a barrier layer 162 of GaN about 70 Å thick was formed by supplying either N2 or H2, NH3 and TMG.
  • Then, a [0049] well layer 161, a barrier layer 162 and a well layer 161 were further formed successively in the same condition as described above to thereby form an MQW active layer 160 about 230 Å thick with two cycles in total.
  • A [0050] cap layer 107 of GaN about 140 Å thick was further formed by supplying either N2 or H2, NH3 and TMG.
  • Then, a p-type clad [0051] layer 108, which was made of p-type Al0.12Ga0.88N doped with magnesium (Mg) and which was about 200 Å thick, was formed by keeping the temperature of the substrate 101 at 1150° C. and by supplying either N2 or H2, NH3, TMG, TMA and CP2Mg.
  • Then, a p-[0052] type contact layer 109, which was made of p-type Al0.05Ga0.95N doped with magnesium (Mg) and which was about 600 Å thick, was formed by keeping the temperature of the substrate 101 at 1100° C. and by supplying either N2 or H2, NH3, TMG, TMA and CP2Mg.
  • Then, an etching mask was formed on the p-[0053] type contact layer 109. After a predetermined region of the mask was removed, the non-masked portion of the p-type contact layer 109, the p-type clad layer 108, the MQW active layer 160, the intermediate layer 104 and a part of the high carrier density N+ layer 103 were etched with a chlorine-containing gas by reactive ion etching to thereby expose a surface of the N+ layer 103.
  • Then, a [0054] negative electrode 140 to joined to the N+ layer 103 and a light-transmissible thin-film positive electrode 110 to be joined to the p-type contact layer 109 were formed by the following procedure.
  • (1) After evacuation to a high vacuum of the order of 10[0055] −4 Pa or less, a thin-film positive electrode first layer 111 of Co about 15 Å thick was formed on a surface evenly and a thin-film positive electrode second layer 112 of Au about 60 Å thick was further formed on the thin-film positive electrode first layer 111 of Co by an evaporation apparatus.
  • (2) Then, a photo resist was applied on a surface evenly and then the photo resist laminated on the p-[0056] type contact layer 109 except the light-transmissible thin-film positive electrode 110-forming portion was removed by photolithography.
  • (3) Then, both Co and Au exposed were removed by etching and then the photo resist was removed so that the light-transmissible thin-film [0057] positive electrode 110 was formed on the p-type contact layer 109.
  • (4) Then, a photo resist was applied and a window was formed in a predetermined region on the exposed surface of the N[0058] + layer 103 by photolithography. After evacuation to a high vacuum of the order of 10−4 Pa or less, a vanadium (V) layer 141 about 175 Å thick and an aluminum (Al) layer 142 about 1.8 μm thick were formed successively by evaporation. Then, the photo resist was removed. As a result, the negative electrode 140 was formed on the exposed surface of the N+ layer 103.
  • (5) Then, a heating process for reducing contact resistance between the p-[0059] type contact layer 109 and the light-transmissible thin-film positive electrode 110 was carried out. That is, the atmosphere for the sample was evacuated by a vacuum pump and an O2 gas was supplied to thereby set a pressure of 10 Pa. In this condition, heating was performed for about 4 minutes to keep the atmospheric temperature at about 570° C.
  • To form further a thick-film [0060] positive electrode 120 on the light-transmissible thin-film positive electrode 110 formed by the aforementioned process, a photo resist was applied evenly onto the light-transmissible thin-film positive electrode 110 and a window was formed in the thin-film positive electrode 120-forming portion of the photo resist. Then, a vanadium (V) layer 121 about 175 Å thick, a gold (Au) layer 122 about 15000 Å thick and an aluminum (Al) layer 123 about 100 Å thick were formed on the light-transmissible thin-film positive electrode 110 successively by evaporation. Thus, the thick-film positive electrode 120 was formed by a lift-off method in the same manner as in the step (4).
  • Then, a [0061] protective film 130 of SiO2 was formed evenly on the upward exposed uppermost layer by electron beam evaporation, and a window was formed in each of portions of the protective film 130 on the thick-film positive electrode 120 and the negative electrode 140 by wet etching through the application of a photo resist and a photolithography process, so that the positive and negative electrodes 120 and 140 were exposed externally and the windows had their areas approximately equal to each other.
  • In this manner, the light-emitting [0062] device 100 was formed. Incidentally, the following expressions (1) and (2) hold for the p-type clad layer 108 of AlxGa1−xN (0<x<1) and the p-type contact layer 109 of AlyGa1−yN (0<y<x) in the light-emitting device 100.
  • y/x=0.05/0.12=0.417  (1)
  • 0.1x ≦y≦0.7x  (2)
  • By forming the light-emitting [0063] device 100 as described above, the composition of the p-type contact layer was made relatively close to the composition of the p-type clad layer. Hence, the difference in crystal lattice constant between the two layers was reduced, so that the p-type contact layer of good quality was able to be grown. Hence, the intensity of light emitted from the light-emitting device was improved.
  • Another reason for improvement in the emitted light intensity of the light-emitting [0064] device 100 according to the present invention compared with the background art was that stress remaining in the light-emitting device was also reduced because the difference in thermal expansion coefficient between the two layers was relatively reduced.
  • Although the first embodiment has shown the case where the p-[0065] type contact layer 109 of AlyGa1−yN (y=0.05≦x) is grown on the p-type clad layer 108 of AlxGa1−xN (x=0.12), the value of the composition ratio y of aluminum (Al) in the p-type contact layer 109 may be selected to be preferably approximately in the range “0.1x≦y≦0.7x”, more preferably approximately in the range “0.4x≦y≦0.5x”. If the value of the composition ratio y in the p-type contact layer is too large, contact resistance between the positive electrode and the p-type contact layer increases, undesirably resulting in increase in the drive voltage of the light-emitting device. If the value of the composition ratio y is contrariwise too small, it is difficult to obtain the aforementioned operation and effect because the composition of the p-type contact layer is not made close to the composition of the p-type clad layer.
  • The light-emitting [0066] device 100 in the first embodiment exhibits high light intensity because these conditions are satisfied sufficiently.
  • For the same reason as described above, the absolute value of the composition ratio y of aluminum (Al) in the p-[0067] type contact layer 109 is also selected to be preferably approximately in the range “0.01≦y≦0.12”, more preferably approximately in the range “0.03≦y≦0.08”.
  • FIG. 2 is a graph showing a correlation between the light emission output of the light-emitting [0068] device 100 according to the present invention and the thickness of the p-type contact layer 109. Because there is a strong correlation between the light emission output of the light-emitting device and the the thickness of the p-type contact layer as shown in FIG. 2, the thickness of the p-type contact layer is selected to be preferably in a range of from 200 Å to 1000 Å both inclusively, more preferably in a range of from 500 Å to 800 Å both inclusively. The light emission output of the light-emitting device exhibits a large value when the thickness of the p-type contact layer is in this range.
  • Generally in this type group III nitride compound semiconductor light-emitting devices, the original function of the p-type contact layer as a p-type low-resistance gallium nitride film containing a dopant for providing acceptors becomes insufficient to obtain a high light emission output if the p-type contact layer is too thin. [0069]
  • Or when the p-[0070] type contact layer 109 is formed or when a heating process such as annealing, or the like, is carried out after the formation of the p-type contact layer 109, solid solution may occur between the p-type contact layer 109 and the p-type clad layer 108 so that aluminum (Al) in the p-type clad layer 108 is eluted into the p-type contact layer 109. Hence, if the p-type contact layer 109 is too thin, not only is it impossible that the value of the composition ratio y of aluminum (Al) in the p-type contact layer 109 is set to be in a desired range but also the light emission output of the light-emitting device varies largely.
  • If the p-[0071] type contact layer 109 is contrariwise too thick, strong stress is imposed on the p-type clad layer 108 and layers below the p-type clad layer 108 because the thermal expansion coefficient of the p-type contact layer 109 is different from that of the p-type clad layer 108. If the p-type contact layer 109 is too thick, it is also difficult to form the p-type contact layer 109 as a desired good-quality crystal structure because dislocation due to lattice mismatching caused by the difference between crystal lattice constants occurs easily in the p-type contact layer 109.
  • It is undesirable from the point of view of quality that the p-[0072] type contact layer 109 is too thick, because both reduction in the intensity of emitted light and increase in individual variation of the intensity of light emitted from the light-emitting devices are brought by these actions.
  • It is also apparent from FIG. 2 that the light-emitting [0073] device 100 in the first embodiment can exhibit high light intensity because the thickness (600 Å) of the p-type contact layer 109 satisfies the aforementioned requirement sufficiently.
  • (Second Embodiment) [0074]
  • FIG. 3 is a typical sectional view showing a flip chip type semiconductor light-emitting [0075] device 200 according to the present invention. A buffer layer 102 of aluminum nitride (AlN) about 200 Å thick is provided on a sapphire substrate 101. An N+ layer 103 of a high carrier density, which is made of GaN doped with silicon (Si) and which is about 4.0 μm thick, is further formed on the buffer layer 102. An intermediate layer 104 of non-doped In0.03Ga0.97N about 1800 Å thick is further formed on the N+ layer 103.
  • An n-type clad [0076] layer 105 and an MQW active layer 160, which is composed of GaN layers and Ga0.8In0.2N layers, are further formed on the intermediate layer 104 successively in the same manner as in the light-emitting device 100 according to the first embodiment. A cap layer 107 of GaN about 140 Å thick and a p-type clad layer 108, which is made of Al0.12Ga0.88N doped with magnesium (Mg) and which is about 200 Å thick, are formed on the MQW active layer 160 successively. A p-type contact layer 109 of Mg-doped Al0.05Ga0.95N about 600 Å thick is further formed on the p-type clad layer 108.
  • Further, a multilayer thick-[0077] film electrode 220 is formed on the p-type contact layer 109 by metal evaporation whereas a negative electrode 240 is formed on the N+ layer 103. The multilayer thick-film electrode 220 has a three-layered structure consisting of a first metal layer 221 joined to the p-type contact layer 109, a second metal layer 222 formed on an upper face of the first metal layer 221, and a third metal layer 223 formed on an upper face of the second metal layer 222.
  • The [0078] first metal layer 221 is a metal layer of rhodium (Rh) or platinum (Pt) about 0.3 μm thick joined to the p-type contact layer 109. The second metal layer 222 is a metal layer of gold (Au) about 1.2 μm thick. The third metal layer 223 is a metal layer of titanium (Ti) about 30 Å thick.
  • The [0079] negative electrode 240 of a two-layered structure is formed by successively laminating a vanadium (V) layer 241 about 175 Å thick and an aluminum (Al) layer 242 about 1.8 μm thick on the partly exposed portion of the high carrier density N+ layer 103.
  • A [0080] protective film 230 constituted by an SiO2 film is formed between the multilayer thick-film positive electrode 220 and the negative electrode 240 which are formed as described above. The protective layer 230 covers, from the N+ layer 103 exposed for forming the negative electrode 240, a side face of the MQW active layer 160, a side face of the p-type clad layer 108 and a side face of the p-type contact layer 109 and a part of the upper face of the p-type contact layer 109, which are exposed by etching, and further covers a side face of the first metal layer 221, a side face of the second metal layer 222 and a part of the upper face of the third metal layer 223. The third metal layer 223-covering portion of the protective film 230 constituted by an SiO2 film is 0.5 μm thick.
  • As described above, a three-layered structure consisting of a first metal layer of rhodium (Rh) or platinum (Pt), a second metal layer of gold (Au), and a third metal layer of titanium (Ti) is applied to the multilayer thick-film [0081] positive electrode 220 in the flip chip type semiconductor light-emitting device 200.
  • Also when the semiconductor light-emitting [0082] device 200 is configured in the aforementioned manner, a semiconductor light-emitting device of higher light intensity than the background-art device can be achieved like the light-emitting device 100.
  • With respect to a group III nitride compound semiconductor light-emitting device such as the light-emitting [0083] device 100 or 200, or the like, for emitting green light in a main wavelength range of from 510 nm to 530 nm, experiment has shown that the device exhibits relatively high light intensity when the thickness of the p-type clad layer 108 is in a range of from 100 Å to 500 Å. More preferably, the thickness of the p-type clad layer 108 is in an optimum range of from 180 Å to 360 Å . When the thickness is in the optimum range, the highest light emission output can be obtained.
  • With respect to a group III nitride compound semiconductor light-emitting device according to the present invention for emitting blue light in a main wavelength range of from 460 nm to 475 nm, experiment has shown that the device exhibits relatively high light intensity when the thickness of the p-type clad [0084] layer 108 is in a range of from 70 Å to 390 Å. More preferably, the thickness of the p-type clad layer 108 is in an optimum range of from 90 Å to 300 Å. When the thickness is in the optimum range, the highest light emission output can be obtained.
  • On the other hand, the composition ratio x of aluminum (Al) in the p-type clad [0085] layer 108 made of AlxGa1−xN is preferably approximately in a range of from 0.10 to 0.14, more preferably in a range of from 0.12 to 0.13. If x is smaller than 0.10, the light emission output is lowered because it is difficult to confine carriers in the active layer. If x is larger than 0.14, the light emission output is also lowered because stress applied to the active layer increases in accordance with the difference between lattice constants of crystals.
  • Although the above embodiments have shown the case where the number of cycles in the MQW [0086] active layer 160 in each of the light-emitting devices 100 and 200 is two, the number of cycles is not particularly limited. That is, the present invention can be applied also to a group III nitride compound semiconductor light-emitting device having an active layer with any number of cycles or any structure.
  • Accordingly, for example, the [0087] active layer 160 may have a SQW (single quantum well) structure.
  • Further, each of group III nitride compound semiconductor layers, inclusive of the buffer layer, the intermediate layer and the cap layer, for constituting the light-emitting device according to the present invention may be made of quaternary, ternary or binary Al[0088] xGayIn1−x−yN (0≦x≦1, 0≦y≦1, 0≦x+y≦1) of an optional crystal mixture ratio.
  • Further, a metal nitride compound such as titanium nitride (TiN), hafnium nitride (HfN), or the like, or a metal oxide compound such as zinc oxide (ZnO), magnesium oxide (MgO), manganese oxide (MnO), or the like, other than the aforementioned group III nitride compound semiconductor may be used as the buffer layer. [0089]
  • Further a group II element such as beryllium (Be), zinc (Zn), or the like, other than magnesium (Mg) may be used as the p-type impurities. To reduce the resistance of the p-type semiconductor layer doped with the p-type impurities more greatly, an activating process such as electron beam irradiation, annealing, or the like, may be further carried out. [0090]
  • Although the above embodiments have shown the case where the high carrier density N[0091] + layer 103 is made of gallium nitride (GaN) doped with silicon (Si), these n-type semiconductor layers may be formed by doping the aforementioned group III nitride compound semiconductor with a group IV element such as silicon (Si), germanium (Ge), or the like, or with a group VI element.
  • Further, silicon carbide (SiC), zinc oxide (ZnO), magnesium oxide (Mgo), manganese oxide (MnO), or the like, other than sapphire may be used as the substrate for crystal growth. [0092]
  • Further, the present invention can be applied to light-receiving devices as well as light-emitting devices. [0093]
  • While the presently preferred embodiment of the present invention has been shown and described, it is to be understood that the disclosure is for the purpose of illustration and that various changes and modification may be made without departing from the scope of the invention as set forth in the appended claims. [0094]

Claims (6)

What is claimed is:
1. A group III nitride compound semiconductor light-emitting device comprising:
a substrate;
a group III nitride compound semiconductor laminated on said substrate;
a p-type clad layer comprising p-type AlxGa1−xN (0<x<1); and
a p-type contact layer comprising p-type AlyGa1−yN (0<y<x) which is lower in a composition ratio of aluminum than said p-type clad layer.
2. A group III nitride compound semiconductor light-emitting device according to claim 1, wherein said p-type contact layer comprises AlyGa1−yN (0.1x≦y≦0.7x).
3. A group III nitride compound semiconductor light-emitting device according to claim 1, wherein said p-type contact layer comprises AlyGa1−yN (0.01≦y≦0.12).
4. A group III nitride compound semiconductor light-emitting device according to claim 1, wherein a thickness of said p-type contact layer is in a range of from 200 Å to 1000 Å.
5. A group III nitride compound semiconductor light-emitting device according to claim 2, wherein a thickness of said p-type contact layer is in a range of from 200 Å to 1000 Å.
6. A group III nitride compound semiconductor light-emitting device according to claim 3, wherein a thickness of said p-type contact layer is in a range of from 200 Å to 1000 Å.
US09/523,463 1999-03-31 2000-03-10 Group III nitride compound semiconductor light-emitting device having a light emission output of high light intensity Expired - Lifetime US6452214B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US10/192,699 US6762070B2 (en) 1999-03-31 2002-07-11 Method of manufacturing group III nitride compound semiconductor light emitting device having a light emission output of high light intensity

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP11-090718 1999-03-31
JP9071899A JP3567790B2 (en) 1999-03-31 1999-03-31 Group III nitride compound semiconductor light emitting device
JPHEI.11-090718 1999-03-31

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US10/192,699 Division US6762070B2 (en) 1999-03-31 2002-07-11 Method of manufacturing group III nitride compound semiconductor light emitting device having a light emission output of high light intensity

Publications (2)

Publication Number Publication Date
US20020014632A1 true US20020014632A1 (en) 2002-02-07
US6452214B2 US6452214B2 (en) 2002-09-17

Family

ID=14006337

Family Applications (2)

Application Number Title Priority Date Filing Date
US09/523,463 Expired - Lifetime US6452214B2 (en) 1999-03-31 2000-03-10 Group III nitride compound semiconductor light-emitting device having a light emission output of high light intensity
US10/192,699 Expired - Lifetime US6762070B2 (en) 1999-03-31 2002-07-11 Method of manufacturing group III nitride compound semiconductor light emitting device having a light emission output of high light intensity

Family Applications After (1)

Application Number Title Priority Date Filing Date
US10/192,699 Expired - Lifetime US6762070B2 (en) 1999-03-31 2002-07-11 Method of manufacturing group III nitride compound semiconductor light emitting device having a light emission output of high light intensity

Country Status (4)

Country Link
US (2) US6452214B2 (en)
EP (1) EP1041650B1 (en)
JP (1) JP3567790B2 (en)
DE (1) DE60034841T2 (en)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060097283A1 (en) * 2003-09-16 2006-05-11 Tetsuya Taki Group III-nitride-based compound semiconductor device
US20060131604A1 (en) * 2000-07-07 2006-06-22 Nichia Corporation Nitride semiconductor device
US20060261355A1 (en) * 2005-05-19 2006-11-23 Nichia Corporation Nitride semiconductor device
US20080041544A1 (en) * 2004-08-25 2008-02-21 John Tsavalas Paper Manufacturing Using Agglomerated Hollow Particle Latex
US20110297956A1 (en) * 2009-03-03 2011-12-08 Panasonic Corporation Method for manufacturing gallium nitride compound semiconductor, and semiconductor light emitting element
US20130146840A1 (en) * 2011-12-07 2013-06-13 Samsung Electronics Co., Ltd. Semiconductor light emitting device
US20150179874A1 (en) * 2013-12-25 2015-06-25 Genesis Photonics Inc. Light emitting diode structure
CN104779328A (en) * 2014-01-13 2015-07-15 新世纪光电股份有限公司 LED (light-emitting diode) structure
US9640712B2 (en) 2012-11-19 2017-05-02 Genesis Photonics Inc. Nitride semiconductor structure and semiconductor light emitting device including the same
US9685586B2 (en) 2012-11-19 2017-06-20 Genesis Photonics Inc. Semiconductor structure
US9780255B2 (en) 2012-11-19 2017-10-03 Genesis Photonics Inc. Nitride semiconductor structure and semiconductor light emitting device including the same
US10319879B2 (en) * 2016-03-08 2019-06-11 Genesis Photonics Inc. Semiconductor structure
US10468549B2 (en) 2016-09-19 2019-11-05 Genesis Photonics Inc. Semiconductor device containing nitrogen

Families Citing this family (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6936859B1 (en) * 1998-05-13 2005-08-30 Toyoda Gosei Co., Ltd. Light-emitting semiconductor device using group III nitride compound
US6657300B2 (en) 1998-06-05 2003-12-02 Lumileds Lighting U.S., Llc Formation of ohmic contacts in III-nitride light emitting devices
JP3567790B2 (en) * 1999-03-31 2004-09-22 豊田合成株式会社 Group III nitride compound semiconductor light emitting device
JP3889933B2 (en) * 2001-03-02 2007-03-07 シャープ株式会社 Semiconductor light emitting device
KR100902109B1 (en) 2001-04-12 2009-06-09 니치아 카가쿠 고교 가부시키가이샤 Gallium nitride compound semiconductor element
US6649942B2 (en) * 2001-05-23 2003-11-18 Sanyo Electric Co., Ltd. Nitride-based semiconductor light-emitting device
US6958497B2 (en) * 2001-05-30 2005-10-25 Cree, Inc. Group III nitride based light emitting diode structures with a quantum well and superlattice, group III nitride based quantum well structures and group III nitride based superlattice structures
US7692182B2 (en) * 2001-05-30 2010-04-06 Cree, Inc. Group III nitride based quantum well light emitting device structures with an indium containing capping structure
JP3812366B2 (en) * 2001-06-04 2006-08-23 豊田合成株式会社 Method for producing group III nitride compound semiconductor device
CN1236535C (en) 2001-11-05 2006-01-11 日亚化学工业株式会社 Semiconductor element
JP2003163373A (en) * 2001-11-26 2003-06-06 Toyoda Gosei Co Ltd Iii nitride compound semiconductor light emitting element
KR100497890B1 (en) * 2002-08-19 2005-06-29 엘지이노텍 주식회사 Nitride semiconductor LED and fabrication method for thereof
JP4143732B2 (en) 2002-10-16 2008-09-03 スタンレー電気株式会社 In-vehicle wavelength converter
JP3979378B2 (en) * 2003-11-06 2007-09-19 住友電気工業株式会社 Semiconductor light emitting device
KR20050051920A (en) * 2003-11-28 2005-06-02 삼성전자주식회사 Flip-chip type light emitting device and method of manufacturing the same
JP2005244207A (en) * 2004-01-30 2005-09-08 Showa Denko Kk Nitride gallium based compound semiconductor luminous element
US7291865B2 (en) * 2004-09-29 2007-11-06 Toyoda Gosei Co., Ltd. Light-emitting semiconductor device
US7731693B2 (en) * 2005-10-27 2010-06-08 Cook Incorporated Coupling wire guide
EP1974389A4 (en) 2006-01-05 2010-12-29 Illumitex Inc Separate optical device for directing light from an led
KR20070102114A (en) * 2006-04-14 2007-10-18 엘지이노텍 주식회사 Nitride semiconductor light-emitting device and manufacturing method thereof
US7789531B2 (en) 2006-10-02 2010-09-07 Illumitex, Inc. LED system and method
JP4191227B2 (en) * 2007-02-21 2008-12-03 昭和電工株式会社 Group III nitride semiconductor light emitting device manufacturing method, group III nitride semiconductor light emitting device, and lamp
JP4962130B2 (en) * 2007-04-04 2012-06-27 三菱化学株式会社 GaN-based semiconductor light emitting diode manufacturing method
WO2009100358A1 (en) 2008-02-08 2009-08-13 Illumitex, Inc. System and method for emitter layer shaping
TWI475717B (en) * 2008-05-09 2015-03-01 Advanced Optoelectronic Tech A semiconductor element that emits radiation
TW201034256A (en) 2008-12-11 2010-09-16 Illumitex Inc Systems and methods for packaging light-emitting diode devices
US8585253B2 (en) 2009-08-20 2013-11-19 Illumitex, Inc. System and method for color mixing lens array
US8449128B2 (en) 2009-08-20 2013-05-28 Illumitex, Inc. System and method for a lens and phosphor layer
US8536615B1 (en) 2009-12-16 2013-09-17 Cree, Inc. Semiconductor device structures with modulated and delta doping and related methods
US8604461B2 (en) * 2009-12-16 2013-12-10 Cree, Inc. Semiconductor device structures with modulated doping and related methods
US8575592B2 (en) * 2010-02-03 2013-11-05 Cree, Inc. Group III nitride based light emitting diode structures with multiple quantum well structures having varying well thicknesses
JP6701628B2 (en) * 2015-05-29 2020-05-27 日亜化学工業株式会社 Semiconductor device and manufacturing method thereof
JP6434878B2 (en) * 2015-09-10 2018-12-05 株式会社東芝 Light emitting device
KR102603411B1 (en) 2017-12-18 2023-11-16 엘지디스플레이 주식회사 Micro led display device

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5432808A (en) * 1993-03-15 1995-07-11 Kabushiki Kaisha Toshiba Compound semicondutor light-emitting device
US5751752A (en) * 1994-09-14 1998-05-12 Rohm Co., Ltd. Semiconductor light emitting device and manufacturing method therefor
US5592501A (en) * 1994-09-20 1997-01-07 Cree Research, Inc. Low-strain laser structures with group III nitride active layers
US5777350A (en) * 1994-12-02 1998-07-07 Nichia Chemical Industries, Ltd. Nitride semiconductor light-emitting device
WO1997048138A2 (en) * 1996-06-11 1997-12-18 Philips Electronics N.V. Visible light emitting devices including uv-light emitting diode and uv-excitable, visible light emitting phosphor, and method of producing such devices
US6031858A (en) * 1996-09-09 2000-02-29 Kabushiki Kaisha Toshiba Semiconductor laser and method of fabricating same
JP3742203B2 (en) * 1996-09-09 2006-02-01 株式会社東芝 Semiconductor laser
JP3223832B2 (en) 1997-02-24 2001-10-29 日亜化学工業株式会社 Nitride semiconductor device and semiconductor laser diode
JPH09219541A (en) * 1997-02-28 1997-08-19 Toshiba Corp Semiconductor light emitting element
KR19980079320A (en) * 1997-03-24 1998-11-25 기다오까다까시 Selective growth method of high quality muene layer, semiconductor device made on high quality muene layer growth substrate and high quality muene layer growth substrate
JPH1168158A (en) * 1997-08-20 1999-03-09 Sanyo Electric Co Ltd Gallium nitride based compound semiconductor device
JP3567790B2 (en) * 1999-03-31 2004-09-22 豊田合成株式会社 Group III nitride compound semiconductor light emitting device

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8698126B2 (en) 2000-07-07 2014-04-15 Nichia Corporation Nitride semiconductor device
US7119378B2 (en) 2000-07-07 2006-10-10 Nichia Corporation Nitride semiconductor device
US9444011B2 (en) 2000-07-07 2016-09-13 Nichia Corporation Nitride semiconductor device
US9130121B2 (en) 2000-07-07 2015-09-08 Nichia Corporation Nitride semiconductor device
US8309948B2 (en) 2000-07-07 2012-11-13 Nichia Corporation Nitride semiconductor device
US7646009B2 (en) 2000-07-07 2010-01-12 Nichia Corporation Nitride semiconductor device
US7750337B2 (en) 2000-07-07 2010-07-06 Nichia Corporation Nitride semiconductor device
US20060131604A1 (en) * 2000-07-07 2006-06-22 Nichia Corporation Nitride semiconductor device
US20080029758A1 (en) * 2000-07-07 2008-02-07 Nichia Corporation Nitride semiconductor device
US20060097283A1 (en) * 2003-09-16 2006-05-11 Tetsuya Taki Group III-nitride-based compound semiconductor device
US7914647B2 (en) 2004-08-25 2011-03-29 Omnova Solutions Inc. Paper manufacturing using agglomerated hollow particle latex
US8333871B2 (en) 2004-08-25 2012-12-18 Omnova Solutions Inc. Paper manufacturing using agglomerated hollow particle latex
US20110162812A1 (en) * 2004-08-25 2011-07-07 John Tsavalas Paper manufacturing using agglomerated hollow particle latex
US20080041544A1 (en) * 2004-08-25 2008-02-21 John Tsavalas Paper Manufacturing Using Agglomerated Hollow Particle Latex
US8981420B2 (en) 2005-05-19 2015-03-17 Nichia Corporation Nitride semiconductor device
US20060261355A1 (en) * 2005-05-19 2006-11-23 Nichia Corporation Nitride semiconductor device
US20110297956A1 (en) * 2009-03-03 2011-12-08 Panasonic Corporation Method for manufacturing gallium nitride compound semiconductor, and semiconductor light emitting element
US8716694B2 (en) * 2011-12-07 2014-05-06 Samsung Electronics Co., Ltd. Semiconductor light emitting device
US20130146840A1 (en) * 2011-12-07 2013-06-13 Samsung Electronics Co., Ltd. Semiconductor light emitting device
US9640712B2 (en) 2012-11-19 2017-05-02 Genesis Photonics Inc. Nitride semiconductor structure and semiconductor light emitting device including the same
US9685586B2 (en) 2012-11-19 2017-06-20 Genesis Photonics Inc. Semiconductor structure
US9780255B2 (en) 2012-11-19 2017-10-03 Genesis Photonics Inc. Nitride semiconductor structure and semiconductor light emitting device including the same
US10381511B2 (en) 2012-11-19 2019-08-13 Genesis Photonics Inc. Nitride semiconductor structure and semiconductor light emitting device including the same
US20150179874A1 (en) * 2013-12-25 2015-06-25 Genesis Photonics Inc. Light emitting diode structure
CN104779328A (en) * 2014-01-13 2015-07-15 新世纪光电股份有限公司 LED (light-emitting diode) structure
CN107968139A (en) * 2014-01-13 2018-04-27 新世纪光电股份有限公司 Light emitting diode construction
CN108054255A (en) * 2014-01-13 2018-05-18 新世纪光电股份有限公司 Light emitting diode construction
US10319879B2 (en) * 2016-03-08 2019-06-11 Genesis Photonics Inc. Semiconductor structure
US10468549B2 (en) 2016-09-19 2019-11-05 Genesis Photonics Inc. Semiconductor device containing nitrogen

Also Published As

Publication number Publication date
JP3567790B2 (en) 2004-09-22
EP1041650A3 (en) 2001-10-10
US20020175332A1 (en) 2002-11-28
US6762070B2 (en) 2004-07-13
JP2000286447A (en) 2000-10-13
EP1041650A2 (en) 2000-10-04
EP1041650B1 (en) 2007-05-16
DE60034841T2 (en) 2008-02-07
DE60034841D1 (en) 2007-06-28
US6452214B2 (en) 2002-09-17

Similar Documents

Publication Publication Date Title
US6452214B2 (en) Group III nitride compound semiconductor light-emitting device having a light emission output of high light intensity
US6841808B2 (en) Group III nitride compound semiconductor device and method for producing the same
JP3909811B2 (en) Nitride semiconductor device and manufacturing method thereof
US20100133506A1 (en) Nitride semiconductor light emitting element and method for manufacturing nitride semiconductor
US6861663B2 (en) Group III nitride compound semiconductor light-emitting device
US6030849A (en) Methods of manufacturing semiconductor, semiconductor device and semiconductor substrate
JP3846150B2 (en) Group III nitride compound semiconductor device and electrode forming method
US6617061B2 (en) Group III nitride compound semiconductor device and group III nitride compound semiconductor light-emitting device
JP5145617B2 (en) N-type nitride semiconductor laminate and semiconductor device using the same
JP3890930B2 (en) Nitride semiconductor light emitting device
JP2006108585A (en) Group iii nitride compound semiconductor light emitting element
US20060169990A1 (en) Group III nitride-based compound semiconductor light-emitting device and method for producing the same
JP2005277374A (en) Light emitting element of group iii nitride compound semiconductor and its manufacturing method
US9064996B2 (en) Group III nitride-based compound semiconductor light-emitting device and production method therefor
KR100680430B1 (en) Iii group nitride compound semiconductor light emitting element
JP3612985B2 (en) Gallium nitride compound semiconductor device and manufacturing method thereof
JPH104210A (en) Iii-group nitrogen compound semiconductor light emitting element
JP3580169B2 (en) Nitride semiconductor device
JP3341576B2 (en) Group III nitride compound semiconductor light emitting device
US20050076828A1 (en) Process for fabrication of III nitride-based compound semiconductors
JP2010040692A (en) Nitride based semiconductor device and method of manufacturing the same
JP2918139B2 (en) Gallium nitride based compound semiconductor light emitting device
JP3836245B2 (en) Gallium nitride compound semiconductor device
US6497944B1 (en) Light-emitting device comprising a gallium-nitride-group compound-semiconductor
JPWO2008153065A1 (en) Semiconductor light emitting device and manufacturing method thereof

Legal Events

Date Code Title Description
AS Assignment

Owner name: TOYODA GOSEI CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KANEYAMA, NAOKI;SAWAZAKI, KATSUHISA;ASAI, MAKOTO;REEL/FRAME:010632/0332

Effective date: 20000301

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYER NUMBER DE-ASSIGNED (ORIGINAL EVENT CODE: RMPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12