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:
Jul. 18, 1989
Filed:
Dec. 23, 1987
Matthew L Balzan, Roanoke, VA (US);
Arthur E Geissberger, Roanoke, VA (US);
Robert A Sadler, Roanoke, VA (US);
ITT A Division of ITT Corporation Gallium Arsenide Technology Center, Roanoke, VA (US);
Abstract
A process for manufacturing GaAs FET's having refractory metal gates provides for reducing the size of the gate relative to a mask by an etch sequence which results in precisely controlled and repeatable self-limited undercutting of the mask. A reactive ion etch of the refractory metal in a CF.sub.4 O.sub.2 plasma containing an inert gas provides the self-limiting undercut at a pressure in the range of 175-250 mTorr when the power is less than 0.15 W/cm.sup.2. Preceeding the undercut, an anisotropic RIE in a CF.sub.4 plasma can be employed to clear unmasked areas of the refractory metal and an initial sputter cleaning in argon improves the quality of the initial etch.