Procédé de cristallisation d'une matière semi-conductrice

A method of producing a semiconductor body of uniform resistivity suitable for use in transistors and rectifiers comprises crystallizing from a melt consisting of the semiconductor as major ingredient and two significant impurity solutes as minor ingredients, the solutes being either of opposite con...

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Bibliographische Detailangaben
Hauptverfasser:	SANFORD INDIG,GEORGE, GARDNER PFANN,WILLIAM
Format:	Patent
Sprache:	fre
Schlagworte:	AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE APPARATUS THEREFOR BASIC ELECTRIC ELEMENTS CHEMISTRY CRYSTAL GROWTH ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR ELECTRICITY GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS METALLURGY PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE REFINING BY ZONE-MELTING OF MATERIAL SEMICONDUCTOR DEVICES SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE SINGLE-CRYSTAL-GROWTH TECHNICAL SUBJECTS COVERED BY FORMER USPC TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL
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Beschreibung
Zusammenfassung:	A method of producing a semiconductor body of uniform resistivity suitable for use in transistors and rectifiers comprises crystallizing from a melt consisting of the semiconductor as major ingredient and two significant impurity solutes as minor ingredients, the solutes being either of opposite conductivity imparting types and having values of 1-k (k being the distribution coefficient) of the same sign, or of the same conductivity imparting type but having values of 1-k of opposite signs. The ratio of the concentration in atoms/c.c. of one solute to that of the other is between 0.8 and 1.2 times the absolute value of the ratio of the growth rate coefficient of the distribution coefficient of the other solute to that of said one solute for a desired growth rate. Typical systems of the first type mentioned above are germanium containing gallium and antimony, indium and arsenic, or indium and antimony, and silicon containing gallium and antimony, arsenic and boron, or phosphorus and boron. Two typical systems of the second type are germanium containing gallium and boron, and indium antimonide containing zinc and cadmium. It is demonstrated mathematically in the Specification that the uncompensated activator concentration in the crystallizing material and hence the resistivity is far less sensitive to changes in growth conditions with time and variations in such conditions over the cross-section of the freezing interface than that of material of the same resistivity crystallized from a melt containing only a single significant impurity solute, particularly when the ratio of concentrations is equal to the aforesaid ratio. Additional significant impurity solutes or impurities for controlling the carrier lifetime of the material may also be incorporated in the melt. The crystallizing process may be a normal freezing operation such as crystal pulling, or a zone melting process. Compensation for changing concentration in the melt may be effected by gradually changing the growth rate as the process proceeds. Specifications 727,678 and 769,673 are referred to.