United States Patent 3,490,140
January 20, 1970

Methods For Making Semiconductor Devices
Stephen Knight
Michiyuki Uenohara

Filed October 5, 1967
Image of US PATENT 3,490,140

Abstract of the Disclosure

Epitaxial gallium arsenide bulk-effect diodes are made by the following process: an n-conductivity layer is grown on a slice of n+ gallium arsenide; an n++ layer is grown on the n layer; a silver-germanium mixture, or other high temperature alloy or metal, is evaporated on the n++ layer and alloyed at about 600 degrees centigrade; the alloy layer is covered with evaporated or electroplated gold or silver; the thickness of the n+ slice is reduced by chemical polishing; an indium-gold, or other lower temperature alloy, layer is evaporated on the n+ slice and alloyed at about 500 degrees centigrade; the indium-gold layer is electroplated with gold or silver; the entire structure is cut by etching into individual elements; and each element is bonded between opposite conductive studs.
Figure descriptions: cover graphic

  • Figure 1 is a flow chart of a process for making epitaxial semiconductor devices in accordance with one embodiment of the invention.
  • Figure 3 is a schematic illustration of part of the semiconductor structure of a partially fabricated semiconductor structure in accordance with the process of Figure 1.
  • Figure 5 is a flow chart indicating steps of an alternative embodiment of the invention which differ from corresponding steps of the chart of Figure 1.

 Citations [54]:
3,290,753 12/1966 Chang 3,423,823 01/1969 Ansley 3,391,023 07/1968 Frescura 3,400,309 09/1968 Doo 3,407,479 10/1968 Fordemoact 3,411,200 11/1968 Formigone
National Museum of American History
HomeSearchChip TalkChip FunPatentsPeoplePicturesCreditsCopyrightComments