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. 30, 1995
Filed:
Feb. 02, 1994
Tetsuji Nagayama, Kanagawa, JP;
Toshiharu Yanagida, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A selecting anisotropic etching method for a GaAs/AlGaAs stacked system is disclosed. In a process for forming a recess for an HEMT gate, an n.sup.+ --GaAs layer on an n.sup.+ --AlGaAs layer is etched using a COS (carbonyl sulfide) /SF.sub.6 / CL.sub.2 mixed gas. The etching proceeds with radicals F.sup.* and Cl.sup.* as main etchants. On the other hand, carbonyl groups and C-O linkages derived from COS are introduced into a sputtered product of the resist mask for producing a carbonaceous polymer having a tough structure. The carbonaceous polymer forms a sidewall protective layer in conjunction with sulphur yielded from COS to contribute to anisotropic etching. It is possible with the present method to diminish the amount of the carbonaceous polymer necessary for procuring anisotropy to assure high selectivity, low pollution and low damage process.