The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 29, 1988
Filed:
Feb. 20, 1987
Surinder Krishna, Fremont, CA (US);
Fairchild Semiconductor Corporation, Cupertino, CA (US);
Abstract
A bipolar/CMOS process includes bipolar transistors having emitters formed in less than a minimal masking dimension. An opening is formed through a polycrystalline silicon layer deposited on a silicon substrate. After coating the sides of the opening with silicon dioxide, the intrinsic base region of the bipolar transistor and the emitter region are implanted. The extrinsic base is formed by outdiffusion from the polycrystalline silicon layer. The structure includes an epitaxial layer which is more strongly doped below its surface than at its surface to enhance the performance of CMOS transistors formed therein. Additionally, the bipolar and complementary MOS transistors are self-aligned to each other by the manner in which the buried layers are formed.