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:
Oct. 16, 2001
Filed:
Sep. 23, 1999
Eiji Nakagawa, Kyoto, JP;
Seiichi Yamamoto, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
A power transistor comprising a collector region formed in a semiconductor substrate, a base region formed within the collector region, and a hoop-shaped emitter region formed within the base region. The hoop-shaped emitter region divides the base region into an external section and at least one internal section surrounded by the emitter region on the substrate surface, the external and internal base sections being connected within the substrate. A base contact is formed on the surface of each internal base section surrounded by the emitter region. By this design, the electric current is more uniform within the emitter region, and safe operating area (SOA) destruction can be prevented. The invention is also directed to semiconductor integrated circuit devices using the above power transistor, and a method of forming the same.