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:
Nov. 21, 1995
Filed:
Mar. 10, 1994
Madjid Hafizi, Santa Monica, CA (US);
William E Stanchina, Thousand Oaks, CA (US);
William W Hooper, Westlake Village, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
A photoresist process combined with wet chemical etching and silicon oxide evaporation and self-aligned lift-off is used to reduce the parasitic (extrinsic) base-collector junction capacitance (C.sub.BC) of InP-based heterojunction bipolar transistors (HBTs). At least a portion of the mesa related to the base contact is etched around the intrinsic device area and then back-filled with evaporated oxide. The base contact pad is then formed over the back-filled oxide, thus reducing the extrinsic device area. This process provides a self-aligned etching of a mesa and deposition and lift-off of the back-fill oxide in one single photoresist processing step. The process is simple and reproducible and provides very high yield. It also eliminates the need for costly and complicated dry-etching techniques.