WO2001045120A2 - Variable capacitor and associated fabrication method - Google Patents
Variable capacitor and associated fabrication method Download PDFInfo
- Publication number
- WO2001045120A2 WO2001045120A2 PCT/IB2000/002051 IB0002051W WO0145120A2 WO 2001045120 A2 WO2001045120 A2 WO 2001045120A2 IB 0002051 W IB0002051 W IB 0002051W WO 0145120 A2 WO0145120 A2 WO 0145120A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- substrate
- bimoφh
- electrode
- layer
- capacitor plate
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G5/00—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture
- H01G5/16—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture using variation of distance between electrodes
- H01G5/18—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture using variation of distance between electrodes due to change in inclination, e.g. by flexing, by spiral wrapping
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
- B81B3/0035—Constitution or structural means for controlling the movement of the flexible or deformable elements
- B81B3/0056—Adjusting the distance between two elements, at least one of them being movable, e.g. air-gap tuning
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
- F03G7/00—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for
- F03G7/06—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G5/00—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture
- H01G5/16—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture using variation of distance between electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/0036—Switches making use of microelectromechanical systems [MEMS]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H59/00—Electrostatic relays; Electro-adhesion relays
- H01H59/0009—Electrostatic relays; Electro-adhesion relays making use of micromechanics
- H01H2059/0063—Electrostatic relays; Electro-adhesion relays making use of micromechanics with stepped actuation, e.g. actuation voltages applied to different sets of electrodes at different times or different spring constants during actuation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H59/00—Electrostatic relays; Electro-adhesion relays
- H01H59/0009—Electrostatic relays; Electro-adhesion relays making use of micromechanics
- H01H2059/0072—Electrostatic relays; Electro-adhesion relays making use of micromechanics with stoppers or protrusions for maintaining a gap, reducing the contact area or for preventing stiction between the movable and the fixed electrode in the attracted position
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H59/00—Electrostatic relays; Electro-adhesion relays
- H01H59/0009—Electrostatic relays; Electro-adhesion relays making use of micromechanics
- H01H2059/0081—Electrostatic relays; Electro-adhesion relays making use of micromechanics with a tapered air-gap between fixed and movable electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H61/00—Electrothermal relays
- H01H2061/006—Micromechanical thermal relay
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H59/00—Electrostatic relays; Electro-adhesion relays
- H01H59/0009—Electrostatic relays; Electro-adhesion relays making use of micromechanics
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H61/00—Electrothermal relays
- H01H61/02—Electrothermal relays wherein the thermally-sensitive member is heated indirectly, e.g. resistively, inductively
Definitions
- the present invention relates generally to variable capacitors and associated fabrication methods and, more particularly, to microelectromechanical system (MEMS) variable capacitors having a high Q and associated fabrication methods.
- MEMS microelectromechanical system
- MEMS Microelectromechanical structures
- other microengineered devices are presently being developed for a wide variety of applications in view of the size, cost and reliability advantages provided by these devices.
- one advantageous MEMS device is a variable capacitor in which the interelectrode spacing between a pair of electrodes is controllably varied in order to selectively vary the capacitance between the electrodes.
- conventional MEMS variable capacitors include a pair of electrodes, one of which is typically disposed upon and fixed to the substrate and the other of which is typically carried on a movable actuator or driver.
- the movable actuator is typically formed by micromachining the substrate such that very small and very precisely defined actuators can be constructed.
- variable capacitors While a variable capacitor can be utilized for many applications, tunable filters frequently utilize variable capacitors in order to appropriately tune the filter to pass signals having predetermined frequencies, while rejecting signals having other frequencies.
- the tunable filter For tunable filters that are utilized for high frequency applications, such as applications involving radio frequency (RF) signals, the tunable filter preferably has a low loss and a high Q, i.e., a high quality factor.
- variable capacitors that include electrodes formed of conventional metals generally do not have a sufficiently high Q for high frequency applications. While electrodes formed of superconducting materials would advantageously increase the Q of the resulting variable capacitor, the use of superconducting materials is generally not compatible with the micromachining techniques, such as required to fabricate the actuator of a conventional MEMS variable capacitor.
- the chemicals i.e., the etchants
- the elevated temperatures in the range of 400°C or greater, required for conventional micromachining will cause damage to the temperature-sensitive superconducting materials.
- MEMS variable capacitors that have improved performance characteristics are desired for many applications.
- tunable filters having a higher Q so as to be suitable for filtering high frequency signals are desirable, but are currently large in size, expensive to fabricate and have limited performance characteristics.
- variable capacitor is therefore provided that is micromachined so as to be precisely defined and extremely small, while also including electrodes formed of a low electrical resistance material.
- the variable capacitor can be utilized for a wide variety of high performance applications including use as a tunable filter having a high Q.
- the tunable filter can appropriately filter high frequency signals, such as radio frequency and microwave signals.
- the variable capacitor includes a substrate and at least one substrate electrode formed of a low electrical resistance material, such as a high temperature superconducting (HTS) material or a thick metal layer, that is disposed upon the substrate.
- the variable capacitor also includes a bimorph member extending outwardly from the substrate and over the at least one substrate electrode.
- the bimorph member includes first and second layers formed of materials having different coefficients of thermal expansion. The first and second layers of the bimorph member define at least one bimorph electrode such that the establishment of a voltage differential between the substrate electrode and the bimorph electrode moves the bimorph member relative to the substrate electrode, thereby altering the interelectrode spacing.
- the bimorph member serves as the actuator in order to controllably move the bimorph electrode relative to the fixed substrate electrode.
- the variable capacitor can also include a substrate capacitor plate disposed upon the substrate.
- the substrate capacitor plate is also formed of a low electrical resistance material, such as a HTS material or a thick metal layer.
- the bimorph member also preferably defines a bimorph capacitor plate that moves with the bimorph member in response to the voltage differential between the substrate and bimorph electrodes to thereby correspondingly alter the capacitance between the substrate and bimorph capacitor plates. By therefore selectively establishing a voltage differential between the substrate and bimorph electrodes, the bimorph member can be moved relative to the underlying substrate such that the spacing between the substrate and bimorph capacitor plates and the resulting capacitance established therebetween is selectively altered.
- the bimorph member defines the bimorph electrode and the bimorph capacitor plate as one continuous conductive layer of the bimorph member.
- the one single conductive layer serves as both the bimorph electrode and the bimorph conductive plate.
- the bimorph member defines the bimorph electrode and the bimorph capacitor plate to be discrete components.
- the bimorph member preferably defines the bimorph electrode to be in general alignment with the substrate electrode.
- the bimorph member of this embodiment preferably defines the bimorph capacitor plate to be spaced from the bimorph electrode and disposed in general alignment with the substrate capacitor plate.
- the bimorph member can be fabricated from a variety of materials.
- the first layer of the bimorph member can include a metal, such as gold
- the second layer of the bimorph member can include a metal, such as aluminum
- the materials chosen for the layers of the bimorph member will have disparate coefficients of thermal expansion to facilitate proper thermal actuation of the bimorph member.
- the first layer of the bimorph member can include a dielectric material, such as silicon nitride, silicon oxide or a suitable polymer and the second layer of the bimorph member can include a metal, such as gold.
- the materials that form the first and second layers are preferably selected such that the bimorph member curls away from the substrate at a predetermined operating temperature in the absence of an applied voltage as a result of the different coefficients of thermal expansion of the materials that form the first and second layers of the bimorph member.
- the bimorph member can therefore be at least partially uncurled in order to control the spacing between the substrate capacitor plate and the bimorph capacitor plate.
- a method of fabricating a variable capacitor is also provided according to another aspect of the present invention.
- a low electrical resistance material such as a HTS material, is initially deposited upon the substrate to define at least one substrate electrode and, more preferably, both the substrate electrode(s) and the substrate capacitor plate.
- a dielectric layer may be disposed on the at least one substrate electrode and substrate capacitor plate to provide electrical insulation, as needed.
- a sacrificial layer preferably formed of low temperature oxide, metal, or photoresist, is deposited over the substrate electrode, the substrate capacitor plate and the optional dielectric layer.
- a bimorph member that includes a bimorph electrode and, more preferably, both a bimorph electrode and a bimorph capacitor plate is then formed on at least a portion of the sacrificial layer and within a window through the sacrificial layer through which the underlying substrate is exposed. As such, the bimorph member extends outwardly from the substrate and over the substrate electrode(s) and the substrate capacitor plate.
- the sacrificial layer is removed such that the bimorph member curls upwardly and is movable relative to the underlying substrate, the substrate electrode and the substrate capacitor plate in response to a voltage differential between the substrate and bimorph electrodes.
- the bimorph member is formed by depositing a first layer upon the sacrificial layer and within the window through the sacrificial layer through which the underlying substrate is exposed. Thereafter, a second layer is deposited upon the first layer with the first and second layers selected such that the second layer has a different coefficient of thermal expansion than the first layer.
- the deposition of the second layer can include the deposition of a continuous second layer upon the first layer such that the continuous second layer serves as both the bimorph electrode and the bimorph capacitor plate.
- the deposition of the second layer includes forming at least one bimorph electrode upon the first layer and disposed in general alignment with the at least one substrate electrode.
- the deposition of the second layer can include a bimorph capacitor plate that is spaced from the at least one bimorph electrode and is disposed in general alignment with the substrate capacitor plate.
- variable capacitor and an associated fabrication method which permit micromachining techniques to be utilized to fabricate a variable capacitor having an electrode and a capacitor plate formed of a low electrical resistance material, such as HTS material.
- the variable capacitor can be precisely defined and can have a small size, while also having improved performance characteristics relative to conventional variable capacitors.
- the variable capacitors can be used in a variety of applications, including use as tunable filters having a relatively high Q. Since a tunable filter including the variable capacitor of the present invention has a relatively high Q, the tunable filter can be used for filtering signals having high frequencies, such as signals having radio frequencies.
- Figure 1 is a perspective view of a variable capacitor according to one embodiment of the present invention.
- Figure 2 is a cross-sectional side view of the variable capacitor of Figure 1.
- Figure 3 is a cross-sectional view of a variable capacitor having the substrate electrode and substrate capacitor plate countersunk into the substrate in according with another embodiment of the present invention.
- FIGS. 4a - 4b are plan views of the variable capacitor depicting two variations of substrate electrode and substrate capacitor plate configuration and shape, in accordance with an embodiment of the present invention.
- Figure 5 is a cross-sectional view of a variable capacitor having a bimorph member with a non-continuous second layer having distinct bimorph electrodes(s) and bimorph capacitor plate, in accordance with another embodiment of the present invention.
- Figures 6a - 6b are simplified electrical schematics of a two terminal and three terminal variable capacitor, in accordance with embodiments of the present invention.
- Figure 7 is a cross-sectional view of a variable capacitor implementing an array of post-like structures to overcome stiction, in accordance with yet another embodiment of the present invention.
- Figure 8 is a cross-sectional view of a variable capacitor implementing an array of dimples and corresponding islands to overcome stiction, in accordance with another embodiment of the present invention.
- Figures 9a - 9d are cross-sectional views illustrating the sequential operations performed during the fabrication of a HTS variable capacitor according to one embodiment to the present invention.
- Figures 10a- 10b are cross-sectional views illustrating the sequential operations performed during the fabrication of countersunk electrodes and capacitor plates in a non- HTS variable capacitor, in accordance with an embodiment of the present invention.
- the variable capacitor includes a microelectronic substrate 12.
- the substrate preferably has a high dielectric constant, low loss tangent and a coefficient of thermal expansion (CTE) that is similar to the CTE of the capacitor and electrode materials.
- CTE coefficient of thermal expansion
- the substrate can be formed of magnesium oxide (MgO) or other similar materials, such as LaA10 3 or NdCaA10 4 may be used.
- the electrodes and capacitor plates are formed of non-HTS materials, the substrate can be formed of quartz, sapphire, or other suitable substrate materials.
- the variable capacitor 10 also includes at least one substrate electrode 14 disposed upon the substrate 12.
- the substrate electrode is formed of a material having low electrical resistance at the frequencies of interest.
- the substrate electrode is formed of a high temperature superconducting (HTS) material.
- HTS high temperature superconducting
- the substrate electrode of one advantageous embodiment is formed of Yttrium Barium Copper Oxide (YBCO) or Thallium Ba ⁇ um Calcium Copper Oxide (TBCCO).
- the substrate electrode may comp ⁇ se a thick metal layer, such as a thick layer of gold.
- the metal layer must be several times the skin depth of the traversing signal at the frequency of capacitor operation A thick layer of metal will assure low electrical resistance and allow for conductance of the frequencies of interest
- the thickness of the metal layer will be at least two times (2X) the skin depth of the traversing signal at the frequency of operation
- the skin depth is approximately 2 micrometers
- the corresponding substrate electrode will have a thickness of about 4 micrometers to about 6 micrometers
- Electrodes having such a prominent thickness create severe surface topography in the capacitor device and pose difficulty in fabricating the later formed layers in the capacitor construct
- the substrate electrode may be countersunk into the substrate by depositing the thick metal layer m a trench
- Figure 3 illustrates a cross-sectional view of the variable capacitor that has countersunk into the substrate 12 a substrate electrode 14 (and substrate capacitor plate 18) in accordance with an embodiment of the present invention The counters
- a protective dielectric layer 16 optionally covers the substrate electrode 14
- a dielectric layer is preferably used to cover the substrate electrode in the embodiments in which the substrate electrode is formed of HTS material.
- the protective nature of the dielectric layer serves to shield the HTS material during the subsequent fab ⁇ cation steps.
- the dielectric layer protects the HTS mate ⁇ al from the chemicals utilized during the fabrication process, such as the etchants.
- the dielectric layer is typically formed of a mate ⁇ al that is resistant to the chemicals utilized during the fab ⁇ cation process, while also, typically, being a low loss dielectric material.
- the dielectric nature of the mate ⁇ al serves to electrically isolate the substrate electrode from the bimorph member
- the dielectric layer will typically be a relatively thm film, typically, having a thickness less than about 1 micrometer.
- the dielectric layer may comprise a polymeric material or another material suitable for providing protection to the HTS material.
- the dielectric layer 16 may be omitted.
- the protective nature of the dielectric layer is not as critical. If a dielectric layer is used in non-HTS electrode embodiments it is typically employed for the insulating characteristics. As such the dielectric layer in the non-HTS substrate electrode embodiments may comprise an oxide or other suitable dielectric materials. If the dielectric layer is omitted and, thus, air serves as the dielectric, some other type of dielectric element or isolated standoffs will typically be present in the variable capacitor to prevent shorting of the substrate electrode and the bimorph electrode.
- the variable capacitor 10 also includes a substrate capacitor plate 18 disposed upon the substrate 12.
- the substrate capacitor plate is preferably formed of a material exhibiting low electrical resistance at the frequencies of interest.
- the substrate capacitor plate is also preferably formed of a HTS material, such as YBCO or TBCCO.
- the substrate capacitor plate may comprise a thick metal layer, such as a thick layer of gold.
- the thick metal layer must be several times the skin depth of the traversing signal at the frequency of capacitor operation.
- the thickness of the metal layer will be at least two times (2X) the skin depth of the traversing signal at the frequency of operation.
- the substrate capacitor plate 18 may be countersunk into the substrate 12 to alleviate problems related to topography.
- the processing of these components can be accomplished in the same fabrication step(s).
- the substrate capacitor plate is preferably spaced apart from the substrate electrode.
- the substrate capacitor plate and the substrate electrode are illustrated to be approximately the same size and shape, the substrate capacitor plate and the substrate electrode can have different sizes and shapes without departing from the spirit and scope of the present invention. By varying the shape and configuration of the substrate electrode and substrate capacitor plate it is possible to provide for uniform actuation force across the entirety of the bimorph member 20.
- Figures 4a and 4b depict plan views of the variable capacitor 10 detailing alternate shapes and configurations of the substrate electrode and substrate capacitor plate.
- a preferred embodiment of the substrate electrode and capacitor plate configuration shows the substrate electrode 14 disposed on the substrate 12 lengthwise from an area proximate the fixed portion 20a of the subsequently formed bimorph member 20 to an area proximate the farthest reach of the distal portion 20b of the bimorph member.
- the substrate capacitor plate 18 is disposed adjacent to the substrate electrode in similar lengthwise fashion.
- the substrate electrode 14 is U-shaped having the base of the U-shape proximate the fixed portion 20a of the bimorph member 20 and the substrate capacitor plate disposed on the substrate such that it is enclosed on three sides by the U-shaped substrate electrode. Both of these embodiments, as well as other conceivable configuration and shape embodiments are used to insure uniform actuation force is applied across the entire surface of the bimorph member.
- a substrate capacitor plate that is formed of a HTS material is also preferably covered with a protective dielectric layer 16 to protect the substrate capacitor plate from the chemicals employed during the fabrication process and to provide for a dielectric.
- the substrate capacitor plate can be coated with a protective dielectric film of polyimide or another suitable dielectric material.
- the dielectric layer may be disposed in the same processing step(s).
- the substrate capacitor plate is formed of non-HTS materials the dielectric layer 16 may be omitted. If a dielectric layer is used in non-HTS capacitor plate embodiments it may comprise an oxide material or another suitable dielectric material.
- variable capacitor 10 also includes a bimorph member 20 that is controllably moveable relative to the underlying substrate 12 and, therefore, relative to the substrate capacitor plate 18 disposed upon the substrate.
- the proximal end 20a of the biino ⁇ h member is affixed to the substrate by means of an anchor 22 such that the bir ⁇ o ⁇ h member extends outwardly from the substrate in a stairstep fashion and then extends over the substrate electrode to a distal end 20b.
- the bimo ⁇ h member overlies the substrate electrode 14 and the substrate capacitor plate in a cantilevered fashion.
- the anchor shown in Figures 1 and 2 is a simplified rigid anchor that runs across the entire proximal end of the bimo ⁇ h member and allows for the bimo ⁇ h member to extend in a cantilevered fashion. This type of anchor is shown by way of example only.
- Other anchor and suspension structures that serve to establish a point of attachment to the substrate and allow for the predetermined mechanical biasing of the cantilevered portion of the bimo ⁇ h member (i.e. allowing for the bimo ⁇ h member to contact the upper layer of the substrate construct) are also possible and within the inventive concepts herein disclosed.
- the bimo ⁇ h member 20 includes first and second layers 24, 26 formed of materials having different coefficients of thermal expansion.
- the bimo ⁇ h member will move in response to changes in temperature relative to the substrate 10 and, therefore, relative to the substrate capacitor plate 18.
- the materials are preferably selected such that the bimo ⁇ h member is curled away from the substrate at a predetermined operating temperature, such as about 77°K, in the absence of an applied voltage.
- the distal end 20b of the bimo ⁇ h member is curled away from the substrate relative to the proximal end 20a of the bimo ⁇ h member that is affixed to the substrate.
- the bimo ⁇ h member is formed such that the material forming the second layer has a greater coefficient of thermal expansion than the first layer so that the bimo ⁇ h member curls away from the substrate as the bimo ⁇ h member cools to the predetermined operating temperature after the first and second layers have been deposited in a plane parallel to the substrate at temperatures greater than the predetermined operating temperature as described below.
- the bimo ⁇ h member 20 of one advantageous embodiment includes a first layer 24 of a first flexible metallic material and a second layer 26 of a second flexible metallic material.
- the first layer may comprise gold and the second layer may comprise aluminum.
- the first and second metal materials will have contrasting thermal coefficients of expansion to allow for biasing in the bimo ⁇ h structure.
- the first layer may comprise a dielectric material, such as silicon oxide, silicon nitride or a suitable polymeric material and the second layer may comprise a metallic material, such as gold.
- the materials chosen for fabricating the bimo ⁇ h member will characteristically be low electrical resistance materials to allow for operation at high frequencies, such as radio frequencies.
- the bimo ⁇ h member provides for a dielectric layer
- that material will be capable of providing electrical isolation for the chosen materials that comprise the conductive layer of the bimo ⁇ h member.
- HTS materials are used to form the substrate electrode 14 and substrate plate 18 then it is advantageous to choose materials that can be deposited at temperatures that are low enough, such as 250°C or so, so as not to adversely affect the previously deposited HTS elements.
- the bimo ⁇ h member 20 can also include an adhesion layer between the first and second layers 24, 26 in order to secure the first and second layers together.
- the adhesion layer can be formed of different materials, the adhesion layer is typically formed of chromium or titanium. Typically, those embodiments that use materials that pose bonding difficulty, such as gold, will require the inclusion of an adhesion layer.
- the first layer 24 of the bimo ⁇ h member 20 in this embodiment forms the anchor 22 that is affixed to the substrate 10 as well as an elongated member that extends outwardly in a cantilevered fashion from the proximal end 20a proximate the anchor and over the substrate electrode 14 and the substrate capacitor plate 18 to the distal end 20b.
- the second layer 26 of the bimo ⁇ h member of the embodiment depicted in Figures 1 and 2 serves as both the bimo ⁇ h electrode 28 and a bimo ⁇ h capacitor plate 30.
- the first layer can be formed of a flexible metal, a polymeric material, an organic dielectric material or another suitable low loss/low resistance material.
- the second layer is typically formed of a metallic material, such as aluminum or gold. Regardless of the material that forms the first and second layers, the second layer of the bimo ⁇ h member of this embodiment is continuous, that is, the second layer of the bimo ⁇ h member extends from the proximal end 20a to the distal end 20b. In this fashion, the second layer extends continuously over both the substrate electrode 14 and the substrate capacitor plate 18. Nevertheless, the variable capacitor 10 of this embodiment also permits the interelectrode spacing of the substrate electrode and the bimo ⁇ h electrode (i.e.
- the second layer to be varied based upon the voltage differential between the second layer of the bimo ⁇ h member and the substrate electrode, thereby also correspondingly altering the spacing between the substrate capacitor plate and the second layer of the bimo ⁇ h member that serves as the bimo ⁇ h capacitor plate.
- FIG. 5 shows a cross-sectional view of the variable capacitor 10 having a bimo ⁇ h electrode 28 and bimo ⁇ h capacitor plate form the second layer 26 of the bimo ⁇ h member 20, in accordance with a present embodiment of the present invention.
- the bimo ⁇ h electrode and the bimo ⁇ h capacitor plate are distinct elements that are spaced apart from each other.
- the second layer of the bimo ⁇ h member can include a plurality of distinct bimo ⁇ h electrodes
- the second layer of the bimo ⁇ h member generally defines the same number of bimo ⁇ h electrodes as substrate electrodes, such as one bimo ⁇ h electrode and one substrate electrode in the illustrated Figure 5 embodiment.
- the at least one bimo ⁇ h electrode will be disposed so as to generally align and overlie with corresponding substrate electrode(s).
- the second layer of the bimo ⁇ h member also defines a distinct bimo ⁇ h capacitor plate such that the bimo ⁇ h capacitor plate is spaced from each bimo ⁇ h electrode and disposed in general alignment with the substrate capacitor plate.
- the bimo ⁇ h electrode and the bimo ⁇ h capacitor may have approximately the same size and shape, the bimo ⁇ h electrode and the bimo ⁇ h capacitor can have different sizes, shapes and configurations, if so desired.
- the sizing, shaping and configurations of the bimo ⁇ h electrodes and bimo ⁇ h capacitor plate will mirror the sizing, shaping and configuration of the associated substrate electrodes and substrate capacitor plate.
- the spacing between the substrate electrode and second layer/bimo ⁇ h electrode 14, 26/28 and, in turn, the spacing between the bimo ⁇ h capacitor plates and the second layer/bimo ⁇ h capacitor plate 18, 26/30 is controlled by selectively altering the voltages applied to the substrate and bimo ⁇ h electrodes.
- the voltage differential between the substrate and bimo ⁇ h electrodes will cause the bimo ⁇ h member 20 that carries the bimo ⁇ h electrode to be moved relative to the substrate electrode, thereby altering the interelectrode spacing in a controlled fashion.
- any movement of the bimo ⁇ h member relative to the substrate in response to a voltage differential established between the substrate and bimo ⁇ h electrodes also controllably varies the spacing between the bimo ⁇ h capacitor plate and the substrate capacitor plate, thereby also controllably adjusting the resulting capacitance of the variable capacitor 10 of the present invention. Since the capacitance established between a pair of capacitor plates varies according to the inverse of the distance or spacing between the plates, the capacitance of the variable capacitor will increase as the bimo ⁇ h member is uncurled toward the underlying substrate. Correspondingly, the capacitance of the variable capacitor will decrease as the bimo ⁇ h member curls further away from the substrate.
- variable capacitor 10 of the present invention can be used as a tunable filter.
- the filtering characteristics can be controllably modified.
- the filter can be configured to pass signals having a predetermined range of frequency, while rejecting signals having frequencies outside the predetermined range (i.e.
- the filter can be configured to reject a predetermined range of frequency, while passing signals having frequencies outside the predetermined range (i.e. a band-reject filter).
- the substrate electrode and the substrate capacitor are preferably constructed of material(s) that have low electrical resistance for signals having relatively high frequencies, the tunable filter is particularly advantageous for filtering signals having high frequencies, such as signals having radio frequencies.
- the low electrical resistance characteristics of the substrate electrode and the substrate capacitor plate will result in a tunable filter that has a high Q, as desired for many applications.
- the Q factor of the variable capacitors of the present invention and the resulting tunable filter can exceed 2000.
- the variable capacitor is formed as a two-terminal device.
- Figure 6a depicts an electrical schematic drawing of a two-terminal variable capacitor 10 having a substrate electrode 14 and bimo ⁇ h electrode 28 in accordance with an embodiment of the present invention.
- the substrate electrode is connected to a first lead 40 that leads to a first DC bias 42 and a first RF signal 44.
- the bimo ⁇ h electrode is connected to a second lead 46 that leads to a second DC bias 48 and a second RF signal 50.
- the substrate electrode and the bimo ⁇ h electrode serve dual roles as the actuation electrode and the capacitor plate electrode.
- variable capacitor of the present invention when high RF frequencies are encountered during operation the DC bias network has a tendency to interact and degrade the AC signal.
- Figure 6b depicts an electrical schematic of a three-terminal variable capacitor 10 having a substrate electrode 14, a substrate capacitor plate electrode 18 and a bimo ⁇ h electrode 28 (disposed on the bimo ⁇ h member) in accordance with an embodiment of the present invention.
- the substrate electrode is connected to a first lead 40 that leads to a first DC bias 42.
- the substrate capacitor plate is connected to a second lead 52 that leads to a first RF signal 44.
- the bimo ⁇ h electrode is connected to a third lead 54 that leads to a second DC bias 48 and a second RF signal 50; the bimo ⁇ h electrode is left at a floating potential.
- the variable capacitor of the present invention may be susceptible to "stiction".
- Stiction is the term commonly used in the field of MEMS to describe the physical and/or chemical attractive forces that tend to hold two surfaces together in the absence of other secondary forces (i.e. electrostatic force, etc.). Stiction can cause the bimo ⁇ h member to stick to the substrate electrode and capacitor plate after release of the sacrificial layer during fabrication or after release of the electrostatic force during operation.
- the in- operation effect may be minimal and manifest itself as hysteresis in performance or the effect may be much more dramatic and cause the bimo ⁇ h element to remain permanently stuck to the substrate electrode and capacitor plate after the actuation force has been removed.
- Figures 7 and 8 illustrate cross-sectional views of two embodiments of the present invention that serve to alleviate the potential problems related to stiction.
- Figure 7 is a cross-sectional view of a variable capacitor that implements a protective/dielectric layer 16 that forms an array of post-like structures 60.
- the protective/dielectric layer is disposed on the microelectronic substrate 12, the countersunk substrate electrode 14 and the countersunk substrate capacitor plate 18.
- the post-like structures are formed by subjecting a continuous protective/dielectric layer to a pattern and etch process.
- the substrate electrode and/or the substrate capacitor plate comprise an HTS material
- the post-like structures may be formed of a polymeric material or another similar material providing subsequent processing protection to the HTS and electrical isolation to the substrate electrode and capacitor plate.
- the post-like structures may be formed of an oxide material, a nitride material or another suitable dielectric insulating material.
- the post-like structures are formed to subjecting the protective layer to a conventional pattern and etch process prior to disposing a sacrificial layer (not shown in Figure 6) on the protective layer.
- the post-like structures serve to decrease the amount of surface area that the bimo ⁇ h member 20 contacts when the bimo ⁇ h member is attracted to the substrate electrode. By providing for less contact area between the bimo ⁇ h member and the substrate structures, it is possible to lessen the effects of stiction.
- Figure 8 is a cross-sectional view of a variable capacitor 10 that implements an array of dimples 62 on the bimo ⁇ h member 20 and a corresponding array of islands 64 on the substrate 12 in accordance with an embodiment of the present invention.
- An array of dimples (small protrusions) are formed on the underside of the bimo ⁇ h member nearest the microelectronic substrate (i.e. the exposed surface of the first layer 24).
- the dimples serve to provide texturing to the underside of the bimo ⁇ h member.
- the dimples are typically formed during the same process step that provides for the first layer. Therefore, the dimples typically comprise a dielectric insulator, such as a nitride material, an oxide material or another material capable of providing electrical isolation.
- the dimples are typically formed by patterning and etching a secondary sacrificial layer (not shown in Figure 8) that forms a mold of where dimples are to be made in the subsequently disposed first layer of the bimo ⁇ h member.
- the islands are surfaces on the substrate that correspond to the dimples in the bimo ⁇ h member. The islands serve as resting places for the dimples when the bimo ⁇ h member is actuated toward the substrate. In the embodiment shown the islands exist within the countersunk electrode and capacitor plate and between the electrode and capacitor plate. By providing for a resting place, the dimple to island interface creates the necessary gap between the substrate electrode/substrate capacitor plate and the bimo ⁇ h member to thereby prevent shorting.
- a method is also provided according to another aspect of the present invention for fabricating a variable capacitor 10, such as described above in conjunction with Figures 1-2.
- Various stages of the variable capacitor fabrication process are depicted in the cross- sectional views of Figures 9a - 9d, in accordance with an embodiment of the present invention.
- This method details the processing involved in fabricating a variable capacitor having a substrate electrode and capacitor plate formed from an HTS material.
- a layer of HTS material such as YBCO or TBCCO, is initially deposited upon a substrate 12, such as a substrate formed of MgO, LaA10 3 or NdCaA10 or other substrate materials compatible with HTS materials.
- the HTS material is then patterned; such as by ion milling, to define at least one substrate electrode 14 and a substrate capacitor plate 18, spaced from the substrate electrode.
- the substrate electrode and the substrate capacitor plate are preferably coated with a dielectric layer 16, such as a protective film formed of polyimide, or a similar protective film capable of providing an insulating means to the variable capacitor.
- a dielectric layer can be deposited in different manners, typically, the dielectric layer is spun on and then reactive ion etched to produce the intermediate structure in which the substrate electrode and the substrate capacitor plate are each coated with a protective film as shown in Figure 9a.
- a photoimagable protective film can be utilized such that the layer need not be reactive ion etched, but can be patterned by conventional photolithographic techniques.
- the intermediate structure is then coated with a sacrificial layer 80 of a low temperature oxide, such as silicon dioxide.
- a low temperature oxide is utilized to avoid exposing the HTS material that forms the substrate electrode 14 and the substrate capacitor plate 18 to high temperatures (> about 300 degrees Celsius) that could damage the HTS material.
- the low temperature oxide is generally deposited, such as by Plasma Enhanced Chemical Vapor Deposition (PECVD), at a temperature of about 250°C to about 300°C.
- PECVD Plasma Enhanced Chemical Vapor Deposition
- the low temperature oxide is then patterned and etched to open a window 42 to the substrate 12 in which the anchor 22 of the bimo ⁇ h member 20 will subsequently be formed. See, for example, Figure 9b.
- the first layer 24 of the bimo ⁇ h member is then formed upon the sacrificial layer.
- a layer of gold, polymeric material or another suitable dielectric material can be spun onto the sacrificial layer.
- the first layer may then be etched by means of reactive ion etching and annealed to form the structure shown in Figure 9c.
- the second layer 26 of the bimo ⁇ h member 20 can then be deposited on the first layer 24.
- the second layer can be a continuous layer the second layer can alternatively be divided into regions that separately define the bimo ⁇ h electrode and the bimo ⁇ h capacitor plate.
- the metallic material such as aluminum
- the sacrificial layer 80 such as with hydrofluoric (HF) acid
- the sacrificial layer is removed and the distal end 20b of the bimo ⁇ h member is freed so as to curl away from the substrate 12 as shown in Figures 1 and 2.
- the fabrication method of the present invention can include the deposition of an adhesion layer upon the first layer 24 of the bimo ⁇ h member 20 prior to depositing the second layer 26.
- the adhesion layer is formed of a material such as chromium or titanium that is patterned to have the same shape and size as the second layer.
- the variable capacitor 10 of the embodiment depicted in Figures 1 and 2 could have an adhesion layer deposited upon the first layer and the second layer can be deposited upon the adhesion layer in the manner described above.
- the second layer can be more robustly adhered to the first layer, particularly in instances in which the selection of materials for the first and second layers of the bimo ⁇ h member would otherwise dictate that the second layer would not robustly adhere to the first layer.
- an adhesion layer may be desirable is instances in which first layer of the bimo ⁇ h member is formed of gold and the second layer of the bimo ⁇ h member is formed of aluminum.
- a thick layer of metal such as gold is initially countersunk into the substrate.
- the substrate may comprise quartz, GaAs, or other suitable substrate materials.
- Figure 10a illustrates the substrate 12 having a layer of poly-silicon material 82 and a layer of photoresist 84 disposed thereon. The photoresist material is exposed and developed to define those regions on the substrate where trenches will be fabricated. After development of the photo resist the poly-silicon layer and the substrate are etched away to define the trenches 86.
- metal has been disposed in the trenches to form the countersunk substrate electrode 14 and the countersunk substrate capacitor plate 18 and the remaining photoresist and poly-silicon has been stripped away.
- variable capacitors 10 may be used in applications that demand high Q, such as tunable filters for high frequency applications as described above.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002361511A CA2361511A1 (en) | 1999-12-15 | 2000-11-28 | Variable capacitor and associated fabrication method |
AU28724/01A AU2872401A (en) | 1999-12-15 | 2000-11-28 | Variable capacitor and associated fabrication method |
EP00993453A EP1157396A1 (en) | 1999-12-15 | 2000-11-28 | Variable capacitor and associated fabrication method |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/461,247 | 1999-12-15 | ||
US09/461,247 US6229684B1 (en) | 1999-12-15 | 1999-12-15 | Variable capacitor and associated fabrication method |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2001045120A2 true WO2001045120A2 (en) | 2001-06-21 |
WO2001045120A3 WO2001045120A3 (en) | 2002-03-28 |
Family
ID=23831777
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2000/002051 WO2001045120A2 (en) | 1999-12-15 | 2000-11-28 | Variable capacitor and associated fabrication method |
Country Status (6)
Country | Link |
---|---|
US (1) | US6229684B1 (en) |
EP (1) | EP1157396A1 (en) |
CN (1) | CN1408120A (en) |
AU (1) | AU2872401A (en) |
CA (1) | CA2361511A1 (en) |
WO (1) | WO2001045120A2 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1350758A2 (en) * | 2002-03-29 | 2003-10-08 | Microsoft Corporation | Electrostatic bimorph actuator |
WO2004000717A2 (en) * | 2002-06-19 | 2003-12-31 | Filtronic Compound Semiconductors Limited | A micro-electromechanical variable capactitor |
US6967761B2 (en) | 2000-10-31 | 2005-11-22 | Microsoft Corporation | Microelectrical mechanical structure (MEMS) optical modulator and optical display system |
US7007471B2 (en) | 2001-12-31 | 2006-03-07 | Microsoft Corporation | Unilateral thermal buckle beam actuator |
US7064879B1 (en) | 2000-04-07 | 2006-06-20 | Microsoft Corporation | Magnetically actuated microelectrochemical systems actuator |
Families Citing this family (89)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6392524B1 (en) | 2000-06-09 | 2002-05-21 | Xerox Corporation | Photolithographically-patterned out-of-plane coil structures and method of making |
US6396677B1 (en) * | 2000-05-17 | 2002-05-28 | Xerox Corporation | Photolithographically-patterned variable capacitor structures and method of making |
US6856225B1 (en) * | 2000-05-17 | 2005-02-15 | Xerox Corporation | Photolithographically-patterned out-of-plane coil structures and method of making |
US6507475B1 (en) * | 2000-06-27 | 2003-01-14 | Motorola, Inc. | Capacitive device and method of manufacture |
US6456420B1 (en) * | 2000-07-27 | 2002-09-24 | Mcnc | Microelectromechanical elevating structures |
US6590267B1 (en) | 2000-09-14 | 2003-07-08 | Mcnc | Microelectromechanical flexible membrane electrostatic valve device and related fabrication methods |
US6377438B1 (en) * | 2000-10-23 | 2002-04-23 | Mcnc | Hybrid microelectromechanical system tunable capacitor and associated fabrication methods |
US6396620B1 (en) | 2000-10-30 | 2002-05-28 | Mcnc | Electrostatically actuated electromagnetic radiation shutter |
US6400550B1 (en) | 2000-11-03 | 2002-06-04 | Jds Uniphase Corporation | Variable capacitors including tandem movers/bimorphs and associated operating methods |
US6437965B1 (en) * | 2000-11-28 | 2002-08-20 | Harris Corporation | Electronic device including multiple capacitance value MEMS capacitor and associated methods |
US20020096421A1 (en) * | 2000-11-29 | 2002-07-25 | Cohn Michael B. | MEMS device with integral packaging |
US6595787B2 (en) * | 2001-02-09 | 2003-07-22 | Xerox Corporation | Low cost integrated out-of-plane micro-device structures and method of making |
US7005314B2 (en) * | 2001-06-27 | 2006-02-28 | Intel Corporation | Sacrificial layer technique to make gaps in MEMS applications |
US6625004B1 (en) * | 2001-08-31 | 2003-09-23 | Superconductor Technologies, Inc. | Electrostatic actuators with intrinsic stress gradient |
US6731492B2 (en) | 2001-09-07 | 2004-05-04 | Mcnc Research And Development Institute | Overdrive structures for flexible electrostatic switch |
WO2003028059A1 (en) * | 2001-09-21 | 2003-04-03 | Hrl Laboratories, Llc | Mems switches and methods of making same |
FR2831705B1 (en) * | 2001-10-25 | 2004-08-27 | Commissariat Energie Atomique | HIGH RATIO VARIABLE MICRO-CAPACITOR AND LOW ACTUATION VOLTAGE |
US20040031912A1 (en) * | 2001-10-31 | 2004-02-19 | Wong Marvin Glenn | Method of eliminating brownian noise in micromachined varactors |
EP1461816B1 (en) * | 2001-11-09 | 2007-01-24 | WiSpry, Inc. | Mems device having contact and standoff bumps and related methods |
DE10159415B4 (en) * | 2001-12-04 | 2012-10-04 | MAX-PLANCK-Gesellschaft zur Förderung der Wissenschaften e.V. | Method for producing a microcoil and microcoil |
WO2003052781A1 (en) * | 2001-12-14 | 2003-06-26 | Midwest Research Institute | Tunable circuit for tunable capacitor devices |
KR100434544B1 (en) * | 2001-12-26 | 2004-06-05 | 삼성전자주식회사 | A processing method for thick film planarization |
US6797163B2 (en) * | 2002-03-28 | 2004-09-28 | Tetra Holding (Us), Inc. | Filtration devices |
US7031136B2 (en) * | 2002-04-09 | 2006-04-18 | Ngimat Co. | Variable capacitors, composite materials |
US6897537B2 (en) * | 2002-06-13 | 2005-05-24 | Wispry, Inc. | Micro-electro-mechanical system (MEMS) variable capacitor apparatuses and related methods |
US6972889B2 (en) * | 2002-06-27 | 2005-12-06 | Research Triangle Institute | Mems electrostatically actuated optical display device and associated arrays |
US7052799B2 (en) * | 2002-06-27 | 2006-05-30 | Vocollect, Inc. | Wearable terminal with a battery latch mechanism |
US7063909B2 (en) * | 2002-08-14 | 2006-06-20 | Hewlett-Packard Development Company, L.P. | Fuel-cell element stack with stress relief and methods |
JP4294590B2 (en) * | 2002-09-25 | 2009-07-15 | エヌエックスピー ビー ヴィ | Electromechanical micro switch device |
EP2096703B1 (en) * | 2002-12-13 | 2016-05-04 | Wispry, Inc. | Varactor apparatuses and methods |
WO2004075032A2 (en) * | 2003-02-19 | 2004-09-02 | Sicel Technologies Inc. | In vivo fluorescence sensors, systems, and related methods operating in conjunction with fluorescent analytes |
US6856499B2 (en) | 2003-03-28 | 2005-02-15 | Northrop Gurmman Corporation | MEMS variable inductor and capacitor |
US7172917B2 (en) * | 2003-04-17 | 2007-02-06 | Robert Bosch Gmbh | Method of making a nanogap for variable capacitive elements, and device having a nanogap |
US6829132B2 (en) * | 2003-04-30 | 2004-12-07 | Hewlett-Packard Development Company, L.P. | Charge control of micro-electromechanical device |
US20050088261A1 (en) * | 2003-10-24 | 2005-04-28 | Lianjun Liu | Method of making a micromechanical device |
US7362199B2 (en) * | 2004-03-31 | 2008-04-22 | Intel Corporation | Collapsible contact switch |
US7000473B2 (en) * | 2004-04-20 | 2006-02-21 | Freescale Semiconductor, Inc. | MEM structure having reduced spring stiction |
JP4754557B2 (en) * | 2004-04-23 | 2011-08-24 | リサーチ・トライアングル・インスティチュート | Flexible electrostatic actuator |
US7411774B2 (en) * | 2004-06-01 | 2008-08-12 | Leeper Ii William F | Voltage variable capacitor |
US7649145B2 (en) * | 2004-06-18 | 2010-01-19 | Micron Technology, Inc. | Compliant spring contact structures |
FR2871790A1 (en) * | 2004-06-22 | 2005-12-23 | Commissariat Energie Atomique | Microspring for micropoint card system, has free end, and sections with layer of one material and two stacks of layers of another two materials, where layer of each stack is set in predetermined state of stress |
WO2006012509A2 (en) * | 2004-07-23 | 2006-02-02 | Afa Controls, Llc | Methods of operating microvalve assemblies and related structures and related devices |
US7302858B2 (en) * | 2004-09-24 | 2007-12-04 | Kevin Walsh | MEMS capacitive cantilever strain sensor, devices, and formation methods |
US7653371B2 (en) * | 2004-09-27 | 2010-01-26 | Qualcomm Mems Technologies, Inc. | Selectable capacitance circuit |
US7657242B2 (en) * | 2004-09-27 | 2010-02-02 | Qualcomm Mems Technologies, Inc. | Selectable capacitance circuit |
US7915018B2 (en) | 2004-10-22 | 2011-03-29 | Ajinomoto Co., Inc. | Method for producing L-amino acids using bacteria of the Enterobacteriaceae family |
JP4744849B2 (en) * | 2004-11-11 | 2011-08-10 | 株式会社東芝 | Semiconductor device |
US7324323B2 (en) * | 2005-01-13 | 2008-01-29 | Lucent Technologies Inc. | Photo-sensitive MEMS structure |
US7319580B2 (en) * | 2005-03-29 | 2008-01-15 | Intel Corporation | Collapsing zipper varactor with inter-digit actuation electrodes for tunable filters |
US8238074B2 (en) * | 2005-05-02 | 2012-08-07 | Epcos Ag | Capacitive RF-MEMS device with integrated decoupling capacitor |
US7345866B1 (en) * | 2005-05-13 | 2008-03-18 | Hrl Laboratories, Llc | Continuously tunable RF MEMS capacitor with ultra-wide tuning range |
US20070145523A1 (en) * | 2005-12-28 | 2007-06-28 | Palo Alto Research Center Incorporated | Integrateable capacitors and microcoils and methods of making thereof |
KR100723227B1 (en) | 2006-02-15 | 2007-05-29 | 삼성전기주식회사 | Tunable film capacitor device |
EP2002511A4 (en) * | 2006-03-08 | 2012-02-29 | Wispry Inc | Tunable impedance matching networks and tunable diplexer matching systems |
EP1832550A1 (en) * | 2006-03-10 | 2007-09-12 | Seiko Epson Corporation | Electrostatic actuation method and electrostatic actuator with integral electrodes for microelectromechanical systems |
US7782594B2 (en) * | 2006-08-18 | 2010-08-24 | Imec | MEMS variable capacitor and method for producing the same |
JP2008132583A (en) * | 2006-10-24 | 2008-06-12 | Seiko Epson Corp | Mems device |
JP4910679B2 (en) * | 2006-12-21 | 2012-04-04 | 株式会社ニコン | Variable capacitor, variable capacitor device, high frequency circuit filter and high frequency circuit |
JP4611323B2 (en) * | 2007-01-26 | 2011-01-12 | 富士通株式会社 | Variable capacitor |
ATE511195T1 (en) | 2007-08-07 | 2011-06-15 | Max Planck Gesellschaft | METHOD FOR PRODUCING A CAPACITOR AND CAPACITOR |
KR100964970B1 (en) * | 2007-08-17 | 2010-06-21 | 한국전자통신연구원 | Releasing apparatus for anti-stiction of microstructure of mems |
US8508447B2 (en) * | 2007-11-19 | 2013-08-13 | Microsoft Corporation | Display device and pixel therefor |
CN100434882C (en) * | 2007-11-20 | 2008-11-19 | 东南大学 | Static excitation resonator capacitor vibration pick-up structure |
KR101413067B1 (en) * | 2008-01-23 | 2014-07-01 | 재단법인서울대학교산학협력재단 | Array variable capacitor apparatus |
US8722537B2 (en) * | 2009-03-19 | 2014-05-13 | Taiwan Semiconductor Manufacturing Company, Ltd. | Multi-sacrificial layer and method |
US8363380B2 (en) * | 2009-05-28 | 2013-01-29 | Qualcomm Incorporated | MEMS varactors |
JP5204066B2 (en) * | 2009-09-16 | 2013-06-05 | 株式会社東芝 | MEMS device |
US20110148837A1 (en) * | 2009-12-18 | 2011-06-23 | Qualcomm Mems Technologies, Inc. | Charge control techniques for selectively activating an array of devices |
KR101104537B1 (en) * | 2010-05-28 | 2012-01-11 | 한국과학기술원 | Variable capacitor and method for driving the same |
JP5637308B2 (en) * | 2011-06-02 | 2014-12-10 | 富士通株式会社 | Electronic device, manufacturing method thereof, and driving method of electronic device |
CN103907166B (en) * | 2011-09-02 | 2017-07-11 | 卡文迪什动力有限公司 | MEMS variable capacitor with enhanced RF performances |
US20130164068A1 (en) * | 2011-12-21 | 2013-06-27 | Apple Inc. | Bonded keyboard and method for making the same |
US9039280B2 (en) * | 2012-01-20 | 2015-05-26 | Purdue Research Foundation | Highly-reliable micro-electromechanical system temperature sensor |
US9354125B2 (en) * | 2012-01-20 | 2016-05-31 | Purdue Research Foundation | Highly-reliable micro-electromechanical system temperature sensor |
EP2898519A4 (en) | 2012-09-20 | 2016-06-01 | Wispry Inc | Micro-electro-mechanical system (mems) variable capacitor apparatuses and related methods |
FR2998417A1 (en) | 2012-11-16 | 2014-05-23 | St Microelectronics Rousset | METHOD FOR PRODUCING AN INTEGRATED CIRCUIT POINT ELEMENT, AND CORRESPONDING INTEGRATED CIRCUIT |
TW201428794A (en) * | 2013-01-02 | 2014-07-16 | Ind Tech Res Inst | Tunable capacitor |
US9711291B2 (en) * | 2013-04-04 | 2017-07-18 | Cavendish Kinetics, Inc. | MEMS digital variable capacitor design with high linearity |
US9939331B2 (en) * | 2014-05-21 | 2018-04-10 | Infineon Technologies Ag | System and method for a capacitive thermometer |
DE102014225934B4 (en) * | 2014-12-15 | 2017-08-03 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Electrostatically deflectable micromechanical component and method for its production |
US10068727B2 (en) | 2015-08-04 | 2018-09-04 | Apple Inc. | Key surface lighting |
US10222265B2 (en) * | 2016-08-19 | 2019-03-05 | Obsidian Sensors, Inc. | Thermomechanical device for measuring electromagnetic radiation |
DE102017214638B4 (en) * | 2017-08-22 | 2021-12-02 | Leibniz-Institut Für Festkörper- Und Werkstoffforschung Dresden E.V. | Process for the production of three-dimensional micro-components and three-dimensional micro-components |
US10497774B2 (en) | 2017-10-23 | 2019-12-03 | Blackberry Limited | Small-gap coplanar tunable capacitors and methods for manufacturing thereof |
US10332687B2 (en) | 2017-10-23 | 2019-06-25 | Blackberry Limited | Tunable coplanar capacitor with vertical tuning and lateral RF path and methods for manufacturing thereof |
US20200064213A1 (en) * | 2018-08-23 | 2020-02-27 | Global Solar Energy, Inc. | Capacitance manometer for high temperature environments |
CN111750905B (en) * | 2019-03-29 | 2023-05-09 | 财团法人工业技术研究院 | Micro-electromechanical sensing device capable of adjusting induction capacitance value |
EP3929960A1 (en) * | 2020-06-26 | 2021-12-29 | Siemens Aktiengesellschaft | Mems switch, method of manufacturing a mems switch and device |
CN112185697A (en) * | 2020-08-18 | 2021-01-05 | 湖南艾迪奥电子科技有限公司 | Composite electrode material for capacitor and preparation method thereof |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3646413A (en) * | 1970-09-25 | 1972-02-29 | Avco Corp | Piezoelectric-driven variable capacitor |
Family Cites Families (48)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3796976A (en) | 1971-07-16 | 1974-03-12 | Westinghouse Electric Corp | Microwave stripling circuits with selectively bondable micro-sized switches for in-situ tuning and impedance matching |
US4141080A (en) | 1976-08-18 | 1979-02-20 | Sperry Rand Corporation | Magneto-resistive readout of a cross-tie wall memory system using a probe and crescent |
US4244722A (en) | 1977-12-09 | 1981-01-13 | Noboru Tsuya | Method for manufacturing thin and flexible ribbon of dielectric material having high dielectric constant |
US4480254A (en) | 1982-09-30 | 1984-10-30 | The Boeing Company | Electronic beam steering methods and apparatus |
US4619001A (en) | 1983-08-02 | 1986-10-21 | Matsushita Electric Industrial Co., Ltd. | Tuning systems on dielectric substrates |
US4554519A (en) | 1983-10-17 | 1985-11-19 | Westinghouse Electric Corp. | Magnetostatic wave delay line |
US4516091A (en) | 1983-12-19 | 1985-05-07 | Motorola, Inc. | Low RCS RF switch and phase shifter using such a switch |
JPS61280104A (en) | 1985-06-05 | 1986-12-10 | Murata Mfg Co Ltd | Dielectric resonator device |
FR2706680B1 (en) | 1986-07-04 | 1995-09-01 | Onera (Off Nat Aerospatiale) | Microwave microstrip and suspended dielectric phase shifter, and application to lobe scanning antenna arrays. |
FR2605146B1 (en) | 1986-09-25 | 1988-12-02 | Alcatel Thomson Faisceaux | ADJUSTABLE BAND FILTER |
US4782313A (en) | 1988-01-12 | 1988-11-01 | General Electric Company | Transmission line shorting switch |
US4853660A (en) | 1988-06-30 | 1989-08-01 | Raytheon Company | Integratable microwave devices based on ferromagnetic films disposed on dielectric substrates |
US5075600A (en) | 1990-06-07 | 1991-12-24 | General Electric Company | Piezoelectrically actuated variable capacitor |
US5406233A (en) | 1991-02-08 | 1995-04-11 | Massachusetts Institute Of Technology | Tunable stripline devices |
US5164688A (en) | 1991-05-31 | 1992-11-17 | Hughes Aircraft Company | Miniature microwave and millimeter wave tuner |
US5168249A (en) | 1991-06-07 | 1992-12-01 | Hughes Aircraft Company | Miniature microwave and millimeter wave tunable circuit |
US5162977A (en) | 1991-08-27 | 1992-11-10 | Storage Technology Corporation | Printed circuit board having an integrated decoupling capacitive element |
US5258591A (en) | 1991-10-18 | 1993-11-02 | Westinghouse Electric Corp. | Low inductance cantilever switch |
US5800575A (en) | 1992-04-06 | 1998-09-01 | Zycon Corporation | In situ method of forming a bypass capacitor element internally within a capacitive PCB |
EP0568064B1 (en) | 1992-05-01 | 1999-07-14 | Texas Instruments Incorporated | Pb/Bi-containing high-dielectric constant oxides using a non-Pb/Bi-containing perovskite as a buffer layer |
US5472935A (en) | 1992-12-01 | 1995-12-05 | Yandrofski; Robert M. | Tuneable microwave devices incorporating high temperature superconducting and ferroelectric films |
US5479042A (en) | 1993-02-01 | 1995-12-26 | Brooktree Corporation | Micromachined relay and method of forming the relay |
US5607631A (en) | 1993-04-01 | 1997-03-04 | Hughes Electronics | Enhanced tunability for low-dielectric-constant ferroelectric materials |
FR2704357B1 (en) | 1993-04-20 | 1995-06-02 | Thomson Csf | Integrated electronic elements with variable electrical characteristics, in particular for microwave frequencies. |
GB9309327D0 (en) | 1993-05-06 | 1993-06-23 | Smith Charles G | Bi-stable memory element |
US5312790A (en) | 1993-06-09 | 1994-05-17 | The United States Of America As Represented By The Secretary Of The Army | Ceramic ferroelectric material |
US5367136A (en) | 1993-07-26 | 1994-11-22 | Westinghouse Electric Corp. | Non-contact two position microeletronic cantilever switch |
US5467067A (en) | 1994-03-14 | 1995-11-14 | Hewlett-Packard Company | Thermally actuated micromachined microwave switch |
US5568106A (en) | 1994-04-04 | 1996-10-22 | Fang; Ta-Ming | Tunable millimeter wave filter using ferromagnetic metal films |
DE4441488A1 (en) | 1994-11-22 | 1996-05-23 | Bosch Gmbh Robert | Superconductor band filter |
US5587943A (en) | 1995-02-13 | 1996-12-24 | Integrated Microtransducer Electronics Corporation | Nonvolatile magnetoresistive memory with fully closed flux operation |
MX9707239A (en) | 1995-03-29 | 1997-11-29 | Minnesota Mining & Mfg | Electromagnetic-power-absorbing composite. |
US5578976A (en) | 1995-06-22 | 1996-11-26 | Rockwell International Corporation | Micro electromechanical RF switch |
US5640133A (en) | 1995-06-23 | 1997-06-17 | Cornell Research Foundation, Inc. | Capacitance based tunable micromechanical resonators |
JP3106389B2 (en) | 1995-08-18 | 2000-11-06 | 株式会社村田製作所 | Variable capacitance capacitor |
US5696662A (en) | 1995-08-21 | 1997-12-09 | Honeywell Inc. | Electrostatically operated micromechanical capacitor |
US5640042A (en) | 1995-12-14 | 1997-06-17 | The United States Of America As Represented By The Secretary Of The Army | Thin film ferroelectric varactor |
US5830591A (en) | 1996-04-29 | 1998-11-03 | Sengupta; Louise | Multilayered ferroelectric composite waveguides |
DE19619585C2 (en) | 1996-05-15 | 1999-11-11 | Bosch Gmbh Robert | Switchable planar high-frequency resonator and filter |
JP3125693B2 (en) | 1996-11-14 | 2001-01-22 | 株式会社村田製作所 | Non-reciprocal circuit device |
US5808527A (en) | 1996-12-21 | 1998-09-15 | Hughes Electronics Corporation | Tunable microwave network using microelectromechanical switches |
US5834975A (en) | 1997-03-12 | 1998-11-10 | Rockwell Science Center, Llc | Integrated variable gain power amplifier and method |
US5880921A (en) | 1997-04-28 | 1999-03-09 | Rockwell Science Center, Llc | Monolithically integrated switched capacitor bank using micro electro mechanical system (MEMS) technology |
US5872489A (en) | 1997-04-28 | 1999-02-16 | Rockwell Science Center, Llc | Integrated tunable inductance network and method |
US5870007A (en) | 1997-06-16 | 1999-02-09 | Roxburgh Ltd. | Multi-dimensional physical actuation of microstructures |
US5914553A (en) | 1997-06-16 | 1999-06-22 | Cornell Research Foundation, Inc. | Multistable tunable micromechanical resonators |
US5930165A (en) | 1997-10-31 | 1999-07-27 | The United States Of America As Represented By The Secretary Of The Navy | Fringe field superconducting system |
US6057520A (en) * | 1999-06-30 | 2000-05-02 | Mcnc | Arc resistant high voltage micromachined electrostatic switch |
-
1999
- 1999-12-15 US US09/461,247 patent/US6229684B1/en not_active Expired - Lifetime
-
2000
- 2000-11-28 EP EP00993453A patent/EP1157396A1/en not_active Withdrawn
- 2000-11-28 WO PCT/IB2000/002051 patent/WO2001045120A2/en active Application Filing
- 2000-11-28 AU AU28724/01A patent/AU2872401A/en not_active Abandoned
- 2000-11-28 CN CN00803826.0A patent/CN1408120A/en active Pending
- 2000-11-28 CA CA002361511A patent/CA2361511A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3646413A (en) * | 1970-09-25 | 1972-02-29 | Avco Corp | Piezoelectric-driven variable capacitor |
Non-Patent Citations (1)
Title |
---|
BENECKE W ET AL: "Applications of silicon microactuators based on bimorph structures" PROCEEDINGS: IEEE MICRO ELECTRO MECHANICAL SYSTEMS. AN INVESTIGATION OF MICRO STRUCTURES, SENSORS, ACTUATORS, MACHINES AND ROBOTS (IEEE CAT. NO.89THO249-3), SALT LAKE CITY, UT, USA, 20-22 FEB. 1989, pages 116-120, XP001032597 1989, New York, NJ, USA, IEEE, USA * |
Cited By (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7782161B2 (en) | 2000-04-07 | 2010-08-24 | Microsoft Corporation | Magnetically actuated microelectromechanical systems actuator |
US7221247B2 (en) | 2000-04-07 | 2007-05-22 | Microsoft Corporation | Magnetically actuated microelectromechanical systems actuator |
US7064879B1 (en) | 2000-04-07 | 2006-06-20 | Microsoft Corporation | Magnetically actuated microelectrochemical systems actuator |
US7168249B2 (en) | 2000-10-31 | 2007-01-30 | Microsoft Corporation | Microelectrical mechanical structure (MEMS) optical modulator and optical display system |
US7151627B2 (en) | 2000-10-31 | 2006-12-19 | Microsoft Corporation | Microelectrical mechanical structure (MEMS) optical modulator and optical display system |
US6967761B2 (en) | 2000-10-31 | 2005-11-22 | Microsoft Corporation | Microelectrical mechanical structure (MEMS) optical modulator and optical display system |
US6990811B2 (en) | 2000-10-31 | 2006-01-31 | Microsoft Corporation | Microelectrical mechanical structure (MEMS) optical modulator and optical display system |
US7007471B2 (en) | 2001-12-31 | 2006-03-07 | Microsoft Corporation | Unilateral thermal buckle beam actuator |
EP1350758A3 (en) * | 2002-03-29 | 2004-12-15 | Microsoft Corporation | Electrostatic bimorph actuator |
US7053519B2 (en) | 2002-03-29 | 2006-05-30 | Microsoft Corporation | Electrostatic bimorph actuator |
EP1350758A2 (en) * | 2002-03-29 | 2003-10-08 | Microsoft Corporation | Electrostatic bimorph actuator |
JP2004001196A (en) * | 2002-03-29 | 2004-01-08 | Microsoft Corp | Micro electromechanical system actuator |
US7249856B2 (en) | 2002-03-29 | 2007-07-31 | Microsoft Corporation | Electrostatic bimorph actuator |
GB2406716B (en) * | 2002-06-19 | 2006-03-01 | Filtronic Compound Semiconduct | A micro-electromechanical variable capactitor |
GB2406716A (en) * | 2002-06-19 | 2005-04-06 | Filtronic Compound Semiconduct | A micro-electromechanical variable capactitor |
WO2004000717A3 (en) * | 2002-06-19 | 2004-10-28 | Filtronic Compound Semiconduct | A micro-electromechanical variable capactitor |
US7440254B2 (en) | 2002-06-19 | 2008-10-21 | Rfmd (Uk) Limited | Micro-electromechanical variable capacitor |
WO2004000717A2 (en) * | 2002-06-19 | 2003-12-31 | Filtronic Compound Semiconductors Limited | A micro-electromechanical variable capactitor |
DE10392851B4 (en) * | 2002-06-19 | 2011-04-14 | RFMD (UK) Ltd., Saltaire, Shipley | Method for manufacturing a microelectromechanical variable capacitor |
Also Published As
Publication number | Publication date |
---|---|
US6229684B1 (en) | 2001-05-08 |
WO2001045120A3 (en) | 2002-03-28 |
AU2872401A (en) | 2001-06-25 |
CA2361511A1 (en) | 2001-06-21 |
CN1408120A (en) | 2003-04-02 |
EP1157396A1 (en) | 2001-11-28 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6229684B1 (en) | Variable capacitor and associated fabrication method | |
US6496351B2 (en) | MEMS device members having portions that contact a substrate and associated methods of operating | |
US6377438B1 (en) | Hybrid microelectromechanical system tunable capacitor and associated fabrication methods | |
US6215644B1 (en) | High frequency tunable capacitors | |
US7053737B2 (en) | Stress bimorph MEMS switches and methods of making same | |
US6074890A (en) | Method of fabricating suspended single crystal silicon micro electro mechanical system (MEMS) devices | |
EP0683921B1 (en) | Microstructures and single mask, single-crystal process for fabrication thereof | |
US5880921A (en) | Monolithically integrated switched capacitor bank using micro electro mechanical system (MEMS) technology | |
US7517769B2 (en) | Integrateable capacitors and microcoils and methods of making thereof | |
EP1658627B1 (en) | Micro electromechanical system switch. | |
US7656071B2 (en) | Piezoelectric actuator for tunable electronic components | |
Giacomozzi et al. | A flexible fabrication process for RF MEMS devices | |
EP1747168A1 (en) | Beam for mems switch | |
US7709285B2 (en) | Method of manufacturing a MEMS device and MEMS device | |
WO2004095490A1 (en) | Bump style mems switch | |
Prophet et al. | Highly-selective electronically-tunable cryogenic filters using monolithic, discretely-switchable MEMS capacitor arrays | |
US20070145523A1 (en) | Integrateable capacitors and microcoils and methods of making thereof | |
US9070524B2 (en) | RF MEMS switch with a grating as middle electrode | |
KR100532991B1 (en) | Fabricating method of rf switch | |
KR100308057B1 (en) | RFswitch and method for fabricating the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 00803826.0 Country of ref document: CN |
|
AK | Designated states |
Kind code of ref document: A2 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ VN YU ZA ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A2 Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG |
|
ENP | Entry into the national phase |
Ref document number: 2361511 Country of ref document: CA Ref document number: 2361511 Country of ref document: CA Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2000993453 Country of ref document: EP |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWP | Wipo information: published in national office |
Ref document number: 2000993453 Country of ref document: EP |
|
AK | Designated states |
Kind code of ref document: A3 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ VN YU ZA ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A3 Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
NENP | Non-entry into the national phase |
Ref country code: JP |