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:
Mar. 28, 1978
Filed:
Mar. 24, 1977
Vassilis George Keramidas, Warren, NJ (US);
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
Abstract
A consistently low resistance ohmic contact is made to an aluminum-containing compound semiconductor by a multilayer deposition and heat treatment process. The process includes the deposition of a transition layer on the semiconductor surface to be contacted and an overlying gold layer to provide external contact. The transition layer consists of aluminum and a shallow dopant element which may be deposited as successive layers or together. After the transition layer and the gold overlay are deposited, the composite is raised to a temperature at which the transition layer is liquid. In cases in which the gold-dopant binary system has a polyphase region, it is preferable to select the thickness of the gold layer such that the gold-dopant alloy is in the solid solution region of the phase diagram of that binary system, to prevent enhanced diffusion to the upper gold surface along grain boundaries. In an exemplary realization, an Al-Sn layer was used to contact n-type GaAlAs.