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. 24, 1992
Filed:
Nov. 01, 1990
Ashok K Kapoor, Palo Alto, CA (US);
Hemraj K Hingarh, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A self-aligned silicide base contact structure for a bipolar transistor, and a process for fabricating the structure are disclosed. The structure has four key elements: a base region 36, a polycrystalline silicon emitter contact region 50, a spacer oxide 60 and 62, and a base contact 74 formed of metal silicide. The spacer oxide is an insulator that electrically isolates the side walls of the emitter contact region from the upper surface of the base region. The spacer oxide is a residual amount of oxide that is left on the side walls of the emitter contact region after anisotropic etching is used to remove most of a covering layer of oxide. The metal silicide base contact is created on an exposed upper surface of the base region, and is formed by first depositing a metal layer on the upper surface of the base region, and then heat treating. Where metal and silicon atoms are in contact, such as along the exposed upper surface of the base region, metal silicide forms.