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:
Nov. 24, 2015
Filed:
Jul. 07, 2014
Fujitsu Limited, Kawasaki-shi, Kanagawa, JP;
Shuichi Tomabechi, Atsugi, JP;
Junji Kotani, Atsugi, JP;
FUJITSU LIMITED, Kawasaki, JP;
Abstract
A semiconductor device includes a first superlattice buffer layer formed on a substrate. A second superlattice buffer layer is formed on the first superlattice buffer layer. A first semiconductor layer is formed by a nitride semiconductor on the second superlattice buffer layer. A second semiconductor layer is formed by a nitride semiconductor on the first semiconductor layer. The first superlattice buffer layer is formed by alternately and cyclically laminating a first superlattice formation layer and a second superlattice formation layer. The second superlattice buffer layer is formed by alternately and cyclically laminating the first superlattice formation layer and the second superlattice formation layer. The first superlattice formation layer is formed by AlGaN, and the second superlattice formation layer is formed by AGaN, where x>y. A concentration of an impurity element doped into the second superlattice buffer layer is higher than that doped into the first superlattice buffer layer.