United States Patent 3,512,056
May 12, 1970

Double Epitaxial Layer High Power, High Speed Transistor
Ting Li Chu
Peter J. Kannam
Donald A. Walczak

Filed April 25, 1967
Image of US PATENT 3,512,056

Abstract of the Disclosure

This invention provides a high power, high speed transistor comprising two epitaxial layers of semiconductor material grown on a large area substrate. The growth of the two epitaxial layers is accomplished in one continuous process. Each epitaxial layer is grown to a desired thickness and has a specific type of semiconductivity having a preferred level of impurity concentration. A required third region of semiconductivity is formed by diffusion in one of the epitaxially grown layers of semiconductor material.
Figure descriptions: cover graphic

  • Figures 1, 2 and 3 are cross-sectional side views of a body of semiconductor material being processed in accordance with the teachings of this invention.
  • Figure 4 is a top view of a semiconductor device showing a preferred emitter edge design.
  • Figures 5 and 6 are views in cross-section of the body of semiconductor material shown in Figures 1, 2, and 3, being processed further in accordance with the teachings of this invention.
  • Figure 7 is a planar view of a slice of semiconductor material showing the location of mesa structures made by processing the slice in accordance with the teachings of this invention.

 Citations [54]:
3,326,729 06/1967 Sigler 3,370,995 02/1968 Lowery 3,271,208 09/1966 Allegretti 3,368,123 02/1968 Rittmann 3,210,621 10/1965 Strull 3,316,130 04/1967 Dash
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