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:
Apr. 04, 1989
Filed:
Oct. 13, 1987
Applicant:
Inventor:
John W Tully, Rolling Hills Estates, CA (US);
Assignee:
Northrop Corporation, Hawthorne, CA (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ;
U.S. Cl.
CPC ...
437 26 ; 148D / ; 148D / ; 148D / ; 148D / ; 357 35 ; 357 48 ; 357 88 ; 357 91 ; 437 22 ; 437 32 ; 437 41 ; 437 74 ; 437192 ; 437247 ; 437944 ; 437987 ;
Abstract
An aluminum liftoff masking process is effected on a prepared gallium arsenide wafer having a base thereon. Successive layers of silicon dioxide and aluminum are deposited on the wafer. The aluminum and silicon dioxide layers are successively etched, including undercutting of the aluminum layer. Base majority carriers are implanted through the windows to the base and refractory metal ohmic contacts are built up in the windows. After forming the base contacts, the base contact areas may be passivated. The aluminum layer and any overlaying layers thereon are removed by etching off the aluminum.