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:
Sep. 24, 1996
Filed:
Jun. 20, 1995
Tomoyuki Yamazaki, Kawasaki, JP;
Shigeyuki Obinata, Kawasaki, JP;
Masahito Otsuki, Kawasaki, JP;
Seiji Momota, Kawasaki, JP;
Tatsuhiko Fujihira, Kawasaki, JP;
Fuji Electric Co., Ltd., Tokyo, JP;
Abstract
Mutual interference is reduced between a main cell portion and a sensing cell portion for detecting the current flowing through the main cell portion of a vertical MOS semiconductor device, and accuracy and reliability of overcurrent detection are improved. In the device, well regions of (p) type are formed between the main and sensing cell portions for capturing the minority carriers. Breakdown of the gate oxide film caused by an open emitter electrode of the sensing cell portion is prevented by forming the (p) type well regions with ring shapes, by spacing the (p) type well regions by 5 to 20 .mu.m, and by adjusting the isolation withstand voltage between the main and sensing cell portions below the withstand voltage of the gate oxide film. A voltage spike is minimized by narrowing the overlap of the detecting and gate electrodes for reduced capacitance between these electrodes.