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:
Jun. 24, 2008
Filed:
Nov. 01, 2005
Masato Irikura, Hyogo, JP;
Yasushi Mochida, Hyogo, JP;
Masahiro Nakayama, Hyogo, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
A nitride semiconductor substrate having a rugged surface being lapped by whetting granules to roughness between Rms5 nm and Rms200 nm, which has a function of reducing dislocations of a GaN, InGaN or AlGaN layer epitaxially grown on the lapped substrate by gathering dislocations in the epi-layer to boundaries of holes, pulling the dislocations to bottoms of the holes. Higher roughness of the nitride substrate degrades morphology of an epitaxially-grown layer thereon but reduces dislocation density to a lower level. Morphology of the epi-layer contradicts the dislocation density of the epi-layer. The nitride semiconductor substrate can reduce dislocation density and can be low cost and useful substrates.