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:
Aug. 03, 1976
Filed:
Mar. 21, 1975
Applicant:
Inventor:
William W Stein, Beaverton, OR (US);
Assignee:
International Telephone and Telegraph Corporation, Nutley, NJ (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
156600 ; 156-3 ; 156-8 ; 156 17 ; 357 30 ; 357 31 ;
Abstract
Preferential etches for Gallium Arsenide and Gallium Aluminum Arsenide materials provide a novel single crystalline layer thin film of GaAs for use as a free standing transmission secondary electron emitter or as a photocathode layer on an intermediate epitaxial layer of GaAlAs. Etching of a central area of a substrate layer of GaAs provides an annular rim supporting structure for the epitaxial GaAlAs and GaAs layers. A particular composition of hydrogen peroxide and ammonium hydroxide preferentially etches GaAs while hydrochloric acid preferentially etches GaAlAs.