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. 22, 2026
Filed:
Jan. 27, 2023
Fuji Electric Co., Ltd., Kawasaki, JP;
Noriaki Yao, Matsumoto-city, JP;
Yuji Kumagai, Matsumoto-city, JP;
FUJI ELECTRIC CO., LTD., Kawasaki, JP;
Abstract
A drift layer has a SJ structure with a parallel pn layer; an n-type buffer layer is between the parallel pn layer and an n-type drain layer. An impurity concentration of the n-type buffer layer is adjusted to be at least equal to that of n-type column regions of the parallel pn layer, to be relatively low in a portion facing the parallel pn layer and approach the impurity concentration of the n-type column regions, and to increase closer to the n-type drain layer. The impurity concentration of the n-type buffer layer is adjusted so that an impurity concentration difference between the n-type buffer layer and the n-type drain layer near the border between the n-type buffer layer and the n-type drain layer is as small as possible. An impurity concentration distribution of the n-type buffer layer is formed by stacking n-type buffer layers in descending order of impurity concentration from the n-type drain layer.