United States Patent 4,199,380
April 22, 1980

Integrated Circuit Method
Michael G. Farrell
Sal T. Mastroianni

Filed November 13, 1978
Image of US PATENT 4,199,380

Abstract of the Disclosure

A method for fabricating self-aligned, walled emitter, oxide isolated integra ted circuits. A layer of oxidation resistant material is formed on an oxide iso lated epitaxial layer on a silicon substrate. A pattern of apertures is opened in the oxidation resistant layer to expose portions of the epitaxial layer. The apertures extend across the oxide isolated silicon material and define the spac es between the contacts of the active devices of the circuit. Dopant impurities are applied through these apertures to form an inactive base region. The subst rate is heated in an oxidizing ambient to form a relatively thick oxide on a portion of the epitaxial layer exposed through the apertures. The oxidation resistant layer is again selectively etched to expose those portions of the epitaxial layer where the active device regions are to be formed. In this step a single mask is used to open a plurality of device regions. The mask is used in conjunction with the oxide isolation and the relatively thick oxide to precisely define the spacing between these regions. Dopant impurities are applied through selected openings to form the active base region. Opposite type dopant impurities are applied through the same openings to form the emitter regions. Dopant impurities are also applied through further selected openings to form base contact areas and collector contact areas. The integrated circuit device thus formed has a base and emitter structure which is bounded on its edges by the isolation oxide or by the relatively thick oxide.
Figure descriptions: cover graphic

  • a cross section of a prior art partially fabricated integrated circuit structure.

 Citations [54]:
4,060,427 11/1977 Barile et al 4,066,473 01/1978 O'Brien 4,110,125 08/1978 Beyer 4,111,726 09/1978 Chen 4,118,250 10/1978 Horng et al 4,131,497 12/1978 Feng et al 4,135,954 01/1979 Chang et al 4,155,777 05/1979 Dunkley et al 4,155,778 05/1979 Antipav
National Museum of American History
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