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:
Mar. 26, 2013
Filed:
May. 04, 2011
Atsushi Yamaguchi, Kyoto, JP;
Norikazu Ito, Kyoto, JP;
Shinya Takado, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
An inventive nitride semiconductor device includes: a substrate; a first buffer layer provided on the substrate, and having a superlattice structure which includes two types of Group III nitride semiconductor sublayers having different compositions and alternately stacked in pairs; a second buffer layer provided on the first buffer layer in contact with the first buffer layer, and having a superlattice structure which includes two types of Group III nitride semiconductor sublayers having different compositions and alternately stacked in pairs; and a device operation layer of a Group III nitride semiconductor provided on the second buffer layer; wherein an average lattice constant LCof the first buffer layer, an average lattice constant LCof the second buffer layer and an average lattice constant LCof the device operation layer satisfy the following expression (1):LC1<LC2<LC3  (1).