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:
May. 17, 1988
Filed:
Dec. 24, 1985
H Barteld Van Rees, Newton Upper Falls, MA (US);
Barry J Liles, Westboro, MA (US);
Raytheon Company, Lexington, MA (US);
Abstract
A field effect transistor includes a substrate of gallium arsenide having a resistivity of at least about 10.sup.7 ohm/cm and a first buffer layer of gallium arsenide disposed over the substrate having a deep level acceptor dopant incorporated into the buffer layer to compensate for donor dopants incorporated into the buffer layer. The concentration of the donor dopants and the acceptor dopant are controlled to provide the buffer layer with a predetermined resistivity characteristic of about 10.sup.7 -10.sup.8 ohm/cm. The concentration of the deep acceptor dopant is substantially constant at about 10.sup.16 acceptors/cc throughout the first buffer layer. The buffer layer preferably has a thickness of at least 2 microns and preferably between 5 and 30 microns. A second buffer layer is disposed over the first buffer layer having a monotonically declining concentration of chromium dopant from about 10.sup.16 to less than about 10.sup.14 acceptors/cc. An active layer and contact layer of suitably n-type doped gallium arsenide are consecutively disposed over at least portions of the second buffer layer.