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:
Apr. 08, 2008
Filed:
Oct. 28, 2004
Takaaki Aoki, Nishikamo-gun, JP;
Yutaka Tomatsu, Okazaki, JP;
Akira Kuroyanagi, Okazaki, JP;
Mikimasa Suzuki, Toyohashi, JP;
Hajime Soga, Toyota, JP;
Takaaki Aoki, Nishikamo-gun, JP;
Yutaka Tomatsu, Okazaki, JP;
Akira Kuroyanagi, Okazaki, JP;
Mikimasa Suzuki, Toyohashi, JP;
Hajime Soga, Toyota, JP;
DENSO CORPORATION, Kariya, JP;
Abstract
A trench-gate type transistor has a gate insulating film formed on an inner wall of a trench. The gate insulating film includes a first portion located on a wall of the trench and a second portion located on upper and bottom portions of the trench. The first portion includes a first oxide film, a nitride film, and a second oxide film. The second portion includes only an oxide film and is thicker than the first portion. Accordingly, electric field concentration on upper and lower corner portions of the trench can be reduced to improve the withstand voltage. In addition, and end of the trench may have an insulation layer that is thicker than the first portion.