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Publication numberUS3102828 A
Publication typeGrant
Publication dateSep 3, 1963
Filing dateJun 1, 1960
Priority dateJun 2, 1959
Also published asDE1446211A1
Publication numberUS 3102828 A, US 3102828A, US-A-3102828, US3102828 A, US3102828A
InventorsCourvoisier Jean
Original AssigneePhilips Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of manufacturing semiconductor bodies
US 3102828 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

t. 1953 J. COURVOISIER 3,102,828

METHOD .OF MANUFACTURING SEMICONDUCTOR BODIES Filed June 1, 1960 Temperature "C I INVEYNTOR JEAN c. F. COURVOISIER.

BY MK AGEN United States Patent G 3 102,828 METHOD F MKNUFACTURING SEMI- CGNDUCTOR BODlES l Jean Conrvoisier, Geneva, Switzerland, assignor to This invention relates to the manufacture of a semiconductor body consisting of two elements, for example silicon and germanium, which body contains at least one zone in which the ratio between the proportions of these elements shows a continuous variation.

It has already been suggested to manufacture such a body by alloying a small amount of germanium to a single crystal of silicon. On cooling, a zone will grow to the silicon; in the material which is the first to solidify and which adjoins the initial crystal, the proportion of silicon will predominate over the proportion of germanium, while the subsequently solidifying parts contain progressively less silicon and more germanium.

it has also been suggested to manufacture a semiconductor body by depositing a semiconductor material, such as germanium or silicon, on a suitable base from vapour or by producing such material by the decomposition of a compound and precipitating it on a base layer. In these processes, the semi-conductors themselves could be used as bases.

This method has a limitation in that it is diflicult to produce single crystal bodies in this manner.

It is an object of the invention to obviate these disadvantages.

According to the invention, at least one element is deposited on the surface of a base which contains the other element and has a melting point higher than that corresponding to the composition of the deposited material, while the temperature of the base is maintained at a value such that the surface is liquid.

Preferably, the base layer is silicon and the deposited material is germanium; however, the deposited material may alternatively be a mixture of germanium and silicon. The invention can also be employed for manufacturing bodies consisting at least partly of two elements forming a semiconductor compound.

It should be noted that the elements may contain impurities, which may be added deliberately.

In order that the invention may readily be carried into effect, an embodiment thereof will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

FIGURE 1 shows schematically an apparatus for the deposition of semiconductor material.

FIGURE 2 is a constitutional diagram for mixtures of silicon and germanium, and

FIGURE 3 is a sectional view of a semiconductor body made by the method in accordance with the invention.

The apparatus shown in FIGURE, 1 comprises an annular cathode 1 of tungsten wire connected to a filament current supply. A molybdenum screen 2 reflects parts of the electrons emitted from the cathode and protects a base 3, on which the material is deposited, against thermal radiation from the cathode. An electrode 4, likewise 3,102,828 Patented Sept. 3, 1963 made of molybdenum, which is maintained at a positive potential of a few hundreds of volts, promotes the flow of electrons towards two anodes 5 and 6 made from silicon and germanium, respectively. The anodes are arranged on graphite supports 7 and 8. The potentials of the anodes 5 and 6 can be adjusted independently by means of a double potentiometer 9, having two sliding contacts 10 and 11. As an alternative, however, these contacts may be coupled to one another so that, when one is at maximum potential, the other is at minimum potential, and conversely. The supports 7 and 8 may be cooled in a manner not shown in the drawing, so that only the upper parts of the semiconductor bodies 5 and 6 are melted by the electron bombardment.

The base 3, which [comprises a single silicon crystal, can be heated by means of a filament 12.

The entire apparatus is arranged in an envelope adapted to be evacuated, which is not shown.

FIGURE 2 is a so-called phase diagram for mixtures of silicon and germanium, in which the ordinate represents the temperature in C. and the abscissae the silicon proportion of the mixture in atomic percent. Both the solidus 2t and the liquidus 21 have a continuous variation from the melting point of silicon at 1420 C. to the melting point of germanium at 960 C. Owing to the fact that these elements can form a continuous series of mixed crystals but do not form an azeotropic system, there can be formed on the surface of the silicon base a layer in which the concentration of the silicon decreases gradually.

The process is initiated by heating the silicon base 3 to about 1400 C. Then a voltage of 5000 volts is applied to the silicon anode 5 and an appreciably lower voltage to the germanium anode 6. The vapour produced will consist substantially of silicon. Gradually the first voltage is reducedand the second voltage is increased, until the vapour produced consists only of germanium. In the meantime, the temperature of the base 3 is gradually reduced to the melting point of germanium, after which the entire heating system is switched out of circuit. Throughout the entire process, the temperature of the base is kept at a value such, depending upon the composition of the deposited material, that the surface layer is liquid.

It is not necessary to use a source supplying silicon vapour. If germanium only is deposited from vapour, the base can be heated to a temperature such that a liquid mixture of silicon and germanium is produced on the surface, and this mixture gradually contains less silicon in proportion as more germanium is deposited and the temperature is reduced.

A semiconductor body made in this manner is shown diagrammatically and greatly enlarged in FIGURE 3. It comprises a silicon layer 30, a layer 31 consisting of a mixture of silicon and germanium and a germanium layer 32. In the layer 31, the proportion of silicon gradually decreases towards the germanium layer 32. Obviously, the process can be stopped at an intermediate stage, for example, before the layer of pure germanium has been formed.

It will be appreciated that the invention can be employed in an analogous manner for manufacturing a body consisting at least in part of a semiconductor compound of two elements which should have a constitutional diagram similar to that of silicon and germanium, that is to say, a non-azeotropic diagram.

What is claimed is:

1. A method of making a semiconductive body containing an alloy portion of silicon and germanium comprising providing a single crystal base member of silicon,

depositing on the surface of said base member a vapor containing both silicon and germanium in a ratio in which the silicon predominates while heating the base member to maintain it at a temperature just above the melting point of the surface composition whereby the surface only is molten, continuing to deposit onvthe surface a vapor with a gradually decreasing proportion of the silicon and a gradually increasing proportion of the germanium while reducing the heating of the base member to maintain a temperature just above the gradually-decreasing melting point of the surface composition which is increasing in germanium, causing a gradual crystallization of the surface melt to form a generally single crystal growing on the base, which grown single crystal has a gradually decreasing proportion of the silicon and a gradually increasing proportion of the germanium.

2. A method as set forth in claim 1 wherein the deposition is continued and the silicon content reduced until only germanium is being deposited on the base.

References Cited in the file of this patent UNITED STATES PATENTS 2,739,088 Pfann Mar. 20', 1956 2,780,569 Hewlett Feb. 5, 1957 2,855,334 Lehovec Oct. 7, 1958 FOREIGN PATENTS 737,527 Great Britain Sept. 28, 1955 742,237, Great Britain Dec. 21, 1955 805,493 Great Britain Dec. 10, 1958 3 4 Great Britain Aug. 19, 1959

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2739088 *Nov 16, 1951Mar 20, 1956Bell Telephone Labor IncProcess for controlling solute segregation by zone-melting
US2780569 *Aug 20, 1952Feb 5, 1957Gen ElectricMethod of making p-nu junction semiconductor units
US2855334 *Aug 17, 1955Oct 7, 1958Sprague Electric CoMethod of preparing semiconducting crystals having symmetrical junctions
GB737527A * Title not available
GB742237A * Title not available
GB805493A * Title not available
GB818564A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3267338 *Apr 20, 1961Aug 16, 1966IbmIntegrated circuit process and structure
US3271179 *Sep 24, 1962Sep 6, 1966Temescal Metallurgical CorpMethod for the manufacture of an optical filter
US3275906 *Aug 14, 1963Sep 27, 1966Nippon Electric CoMultiple hetero-layer composite semiconductor device
US3322575 *Jul 31, 1961May 30, 1967Monsanto CoGraded energy gap photoelectromagnetic cell
US3338760 *Jun 3, 1964Aug 29, 1967Massachusetts Inst TechnologyMethod of making a heterojunction semiconductor device
US3428474 *Jun 24, 1964Feb 18, 1969Bausch & LombMethod for forming ceramic metallic bonds
US3458368 *May 23, 1966Jul 29, 1969Texas Instruments IncIntegrated circuits and fabrication thereof
US3634149 *Oct 25, 1967Jan 11, 1972Philips CorpMethod of manufacturing aluminium nitride crystals for semiconductor devices
US3766447 *Oct 20, 1971Oct 16, 1973Harris Intertype CorpHeteroepitaxial structure
US4165249 *Feb 25, 1977Aug 21, 1979Siemens AktiengesellschaftMethod of purifying germanium bodies
US4357183 *Aug 13, 1980Nov 2, 1982Massachusetts Institute Of TechnologyHeteroepitaxy of germanium silicon on silicon utilizing alloying control
US4861393 *May 28, 1987Aug 29, 1989American Telephone And Telegraph Company, At&T Bell LaboratoriesSemiconductor heterostructures having Gex Si1-x layers on Si utilizing molecular beam epitaxy
US5577642 *Apr 11, 1995Nov 26, 1996Nestec S.A.System for metering a product in powder form
DE1298512B *Mar 13, 1964Jul 3, 1969Telefunken PatentEinrichtung zum Aufdampfen einkristalliner Schichten auf Unterlagen
Classifications
U.S. Classification117/56, 117/939, 148/DIG.590, 148/DIG.740, 257/E21.87, 148/DIG.670, 204/192.25, 148/33.4, 438/936, 257/191
International ClassificationC30B19/10, C30B11/06, H01L21/00, H01L21/18
Cooperative ClassificationH01L21/00, Y10S148/067, H01L21/185, Y10S148/059, C30B19/10, Y10S148/074, C30B11/06, Y10S438/936
European ClassificationH01L21/00, C30B19/10, C30B11/06, H01L21/18B