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. 08, 2011
Filed:
Dec. 14, 2005
Ryota Isono, Hitachi, JP;
Takashi Takeuchi, Hitachi, JP;
Ryota Isono, Hitachi, JP;
Takashi Takeuchi, Hitachi, JP;
Hitachi Cable, Ltd., Tokyo, JP;
Abstract
A field effect transistor (FET) with high withstand voltage and high performance is realized by designing a buffer layer structure appropriately to reduce a leakage current to 1×10A or less when a low voltage is applied. An epitaxial wafer for a field effect transistor comprising a buffer layer, an active layer, and a contact layer on a semi-insulating substratefrom the bottom, and the buffer layerincludes a plurality of layers, and a p-type buffer layer composed of p-type AlGaAs (0.3≦x≦1) is provided as a bottom layer (undermost layer). A Nd product of a film thickness of the p-type buffer layer and a p-type carrier concentration of the p-type buffer layer is within a range from 1×10to 1×10/cm.