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:
Aug. 18, 2015
Filed:
Jan. 15, 2013
Sharp Kabushiki Kaisha, Osaki-shi, Osaka, JP;
Masayuki Hoteida, Osaka, JP;
Nobuaki Teraguchi, Osaka, JP;
Daisuke Honda, Osaka, JP;
Nobuyuki Ito, Osaka, JP;
Masakazu Matsubayashi, Osaka, JP;
Haruhiko Matsukasa, Osaka, JP;
SHARP KABUSHIKI KAISHA, Osaka, JP;
Abstract
An epitaxial wafer for a heterojunction type FET includes an AlN primary layer, a stepwisely composition-graded buffer layer structure, a superlattice buffer layer structure, a GaN channel layer, and a nitride semiconductor electron supply layer, which are sequentially provided on a Si substrate, the stepwisely composition-graded buffer layer structure including a plurality of AlGaN buffer layers provided on each other such that an Al composition ratio is sequentially reduced, an uppermost layer thereof having a composition of AlxGa1−xN (0<x), a plurality of sets of an AlyGa1−yN (y≦1) superlattice constituting layer and an AlzGa1−zN (0<z<y) superlattice constituting layer being provided on each other alternately starting from one of the AlyGa1−yN superlattice constituting layer and the AlzGa1−zN superlattice constituting layer in the superlattice buffer layer structure, the AlxGa1−xN buffer layer and the AlzGa1−zN superlattice constituting layer satisfying x−0.05≦z≦x+0.05.