There are two types I know of, deep and shallow contacts.
I have not worked much with deep contacts but they use Au, Ge and Ni.  One
paper that looks at them is :

A comparative study of Pd_Sn_Au Au_Ge_Au_Ni_Au AuGe_Ni and Ni_AuGe_Ni ohmic
contacts to n_GaAs
M.S. Islam, P.J. McNally
Microelectronic Engineering 40 (1988) 35-42

I have just started using shallow contacts on an HEMT.  The paper is
Low resistance nonspiking ohmic contact for AlGaAs_GaAs high electron
mobility transistors using the Ge_Pd scheme
L.C. Wang et. al.
Appl. Phys. Lett 54 (26) June 1989  pp.2677-79

The shallow contacts use lower temperature anneals but I hear that you can
have trouble with low temperature measurements.

Glen

At 12:01 PM 4/11/2002, you wrote:
>Message: 11
>Date: Thu, 11 Apr 2002 11:04:42 -0400
>From: Liz Shelley 
>To: 
>Subject: [mems-talk] Ohmic Contact to GaAs
>Reply-To: [email protected]
>
>I am looking for some information or literature for
>making ohmic contact to Gallium Arsenide.
>Does anyone know of papers or articles that would give me details for this?
>Thank-you for any information
>Liz Shelley
>Process Development Engineer
>MicroMetrics, Inc
>Londonderry, NH

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Glen A. Landry, Ph.D.
Naval Research Laboratory
Code 6340
4555 Overlook Ave. SW
Washington, DC 20375
USA
Tel.: 202-767-4474 Fax: 202-767-1697
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