Edward J Laskowski

US Patent:

49235648, May 8, 1990

Filed:

Aug 24, 1989

Appl. No.:

7/398116

Inventors:

Jaya Bilakanti - Teaneck NJ
Edward J. Laskowski - Scotch Plains NJ

Assignee:

American Telephone and Telegraph Company - New York NY

International Classification:

H01L 21306
B44C 122
C03C 1500
C03C 2506

US Classification:

156655

Abstract:

An etching process is described for etching aluminum containing III-V semiconductor compounds. The etch solution contains dichromate ion in acid aqueous solution in which the acid is either phosphoric acid or sulfuric acid. The etch solution is highly selective in that it etches the aluminum containing III-V semiconductor compounds without etching significantly other III-V semiconductor compounds not containing aluminum exposed to the same etching solution. the etching process is extremely useful in fabricating a variety of III-V semiconductor devices including heterojunction bipolar transistors, heterojunction field effect transistors and self-enhanced electro optic devices.