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:
Dec. 16, 1997
Filed:
Apr. 30, 1996
Costas Dimitrios Varmazis, Chelmsford, MA (US);
The Whitaker Corporation, Wilmington, DE (US);
Abstract
A metal semiconductor field effect transistor (MESFET) having a reduced control voltage while maintaining appropriate performance characteristics is disclosed. The MESFET is fabricated by a two step implantation technique for fabricating the ohmic contact region in the channel between the source and drain. This implant process results in higher doping levels of the active channel and a increased conductivity. Additionally, this step defines the channel depth, which in turn defines the pinch-off voltage. In the preferred embodiment of the present invention, the channel thickness is on the order of 2000 Angstroms. Parasitic capacitance is reduced to an acceptable level by reduction in the gate length. Finally, after the implantation of donor dopants to effect the active channel, a suitable acceptor dopant, preferably beryllium, is implanted to produce a well defined channel boundary, to reduce the donor dopant tails. This facilitates the control of the pinch-off voltage.