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. 03, 1988
Filed:
Apr. 27, 1987
Jean Vatus, Verrieres le Bouisson, FR;
Jean Chevrier, Gif sur Yvetie, FR;
Thomson-CSF, Paris, FR;
Abstract
The invention pertains to a method for the selective etching of a surface layer which is automatically stopped at a subjacent layer. According to the invention, a first layer of a material containing gallium is selectively etched with respect to a second layer containing aluminium by reactive ion etching in the presence of a pure freon plasma C Cl.sub.2 F.sub.2. At low pressures (0.5 to 2.5 pascals), the etching is anisotropic and makes it possible to etch the gate recess of a field effect transistor. At a higher pressure (6 to 10 pascals), the etching is isotropic and makes it possible to sub-etch the first layer. Application to the manufacture of field effect transistors made of group III-V materials, with low access resistances.