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. 07, 1993
Filed:
Apr. 10, 1992
Yoshiro Baba, Yokohama, JP;
Shunichi Hiraki, Chiba, JP;
Akihiko Osawa, Machida, JP;
Satoshi Yanagiya, Kawasaki, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A vertical MOS transistor comprises a semiconductor substrate, a first impurity region defined on the surface of the semiconductor substrate, a second impurity region defined under the first impurity region, the conduction type of the second impurity region being opposite to that of the first impurity region, a trench engraved on the surface of the semiconductor substrate to cut through the first and second impurity regions deeper than at least the bottom of the second impurity region, and a gate electrode disposed in the trench with a gate insulation film interposing between the wall of the trench and the gate electrode. The gate insulation film is thicker on the bottom of the trench and on part of the side walls of the trench continuous to the bottom than on the other parts.