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:
Jan. 24, 2012
Filed:
Sep. 10, 2009
Takeshi Eri, Hitachi, JP;
Takeshi Meguro, Kitaibaraki, JP;
Takeshi Eri, Hitachi, JP;
Takeshi Meguro, Kitaibaraki, JP;
Hitachi Cable, Ltd., Tokyo, JP;
Abstract
To provide a group-III nitride semiconductor freestanding substrate, with carrier concentration of a peripheral part of a n-type group-III nitride semiconductor freestanding substrate set to be lower than the carrier concentration inside of the peripheral part. In this freestanding substrate, preferably value Δσ obtained by dividing a difference between a maximum value of the carrier concentration and a minimum value of the carrier concentration in a surface of the freestanding substrate by the maximum value of the carrier concentration is greater than 0.05, and the carrier concentration in any place in the surface of the freestanding substrate exceeds 5.0×10cm.