United States Patent 4,180,827
December 25, 1979

NPN/PNP Fabrication Process With Improved Alignment
Harlan R. Gates

Filed Original File Date NA
Image of US PATENT 4,180,827

Abstract of the Disclosure

A double diffused, lateral PNP structure is disclosed which may be formed simultaneously with a vertical NPN structure. The novel feature of the structure is believed to be the vertical projection of the N-type base region for the PNP, down through surrounding diffused P-type collector and into an N-type epitaxial layer between the collector diffusion and buried subbase, an N-type sub-base to electrically contact the base. The N-type epitaxial layer serves as the intrinsic base region permitting contact with the surface. The double diffused base and emitter structure permits a precise intrinsic base width to be formed for lateral PNP. Thus, a high performance PNP can be constructed with compatible high performance NPNs on the same substrate.
Figure descriptions: cover graphic

 Citations [54]:
4,054,900 10/1977 Tokumaru et al 4,058,419 11/1977 Tokumaru et al
National Museum of American History
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