United States Patent 3,474,308
October 21, 1969

Monolithic Circuits Having Matched Complementary Transistors, Sub-Epitaxial And Surface Resistors, And N And P Channel Field Effect Transistors
John W. Kronlage

Filed December 13, 1966
Image of US PATENT 3,474,308

Abstract of the Disclosure

Disclosed are monolithic circuits of the type having matched pairs of complementary transistors formed within respective pockets of an epitaxial layer that extends over one surface of a substrate. Below the emitter and base regions of each transistor is a diffused region of conductivity type opposite to the conductivity of the substrate, and formed within the diffused region below the NPN transistor is a buried region of conductivity type the same as the conductivity type of the substrate for providing a low resistivity path for collector current. In other pockets of the epitaxial layer, there may be formed sub-epitaxial resistors, surface resistors, n-channel field effect transistors and p-channel field effect transistors.
Figure descriptions: cover graphic

  • Figures 1a and 1b, collectively, show a single substrate after the first p-type diffusion upon which six different circuit devices are to be fabricated concurrently in accordance with the process of this invention.
  • Figures 2a and 2b, collectively, show the substrate of Figures 1a and 1b after the preepitaxial n-type diffusion step of the process.

 Citations [54]:
3,423,653 01/1969 Chang 3,327,182 06/1967 Kisinko 3,278,853 10/1966 Lin 3,414,783 12/1968 Moore 3,380,150 04/1968 Kisinko 3,423,650 01/1969 Cohen 3,370,995 02/1968 Lowery 3,404,321 10/1968 Kurosawa 3,387,193 06/1968 Donald 3,404,450 10/1968 Karcher 3,299,329 01/1967 Pollock
National Museum of American History
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