Improvements in or relating to the manufacture of semiconductor valves

摘要

983,074. Semi-conductor devices. GENERAL ELECTRIC CO. Ltd. July 4, 1962 [July 12, 1961], No. 25321/61. Heading H1K. A method of manufacturing a semi-conductor device consists in placing a germanium wafer with substantially the whole of one of its main faces in contact with a metallic support and in heating the assembly in such a manner that heat is conducted to the wafer via the support thus establishing a thermal gradient across the wafer and causing the hottest part only of the wafer to form a molten alloy with part of the support at a temperature lower than the melting point of either the germanium or the basic material of the support, the assembly then being cooled to bond the wafer to the support, the physical characteristics of the unalloyed part of the wafer remaining substantially unchanged during the loading cycle. Preferably, the non-bonded face of the wafer is maintained in contact with a heat sink during the process. The invention is suitable for masking devices such as diodes and transistors; in the embodiment described a high frequency point contact diode is produced. To form the diode a wafer 1 is placed on a support 2 of iron/nickel/cobalt alloy which is held in the well of a stainless steel body 6 itself held in a carbon block 3 through which heating current is passed. This assembly is within a nitrogenfilled glass bell jar 11 in the top of which is a hole through which nitrogen escapes around a stainless steel plunger 9 resting under its own weight on the wafer and acting as a heat sink. The progress of alloying is under the control of an operator observing the process through a microscope (not shown). To complete the diode, Fig. 2 (not shown), the support carrying the wafer is mounted in a brass bush scaled to one end of a quartz tube and a generally similar support bearing a metal whisker which contacts the wafer is mounted in a second brass bush sealed to the other end of the tube. In a variant the wafer support is copper plated and that part of the copper plating in contact with the wafer forms an alloy with the germanium and some of the support material.