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Oxide Free Surfaces of AlAs

IP.com Disclosure Number: IPCOM000074102D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Chicotka, RJ: AUTHOR [+2]

Abstract

In order to prepare ohmic alloy contacts to electrical devices, it is necessary to have clean oxide free surfaces. This is especially true in the case of AlAs. AlAs develops an impervious oxide film very rapidly on exposure to the atmosphere which inhibits efforts to prepare normal alloy contacts. Also, a major difficulty in the preparation of contacts to GaAlAs with high Al content is the surface oxide layer that forms and through which electrical contact cannot be made.

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Oxide Free Surfaces of AlAs

In order to prepare ohmic alloy contacts to electrical devices, it is necessary to have clean oxide free surfaces. This is especially true in the case of AlAs. AlAs develops an impervious oxide film very rapidly on exposure to the atmosphere which inhibits efforts to prepare normal alloy contacts. Also, a major difficulty in the preparation of contacts to GaAlAs with high Al content is the surface oxide layer that forms and through which electrical contact cannot be made.

Clean, oxide free surfaces of AlAs have been prepared in the following manner:

The sample is lapped under kerosene and then washed in acetone. It is then immersed in 0.1 N HCl solution and is then coated with CsF in an argon atmosphere. The sample is then heated in a strip heater under an argon atmosphere until the CsF melts and completely wets the AlAs surface, thereby reacting with the surface and removing an oxide layer and some part of the AlAs surface. After reacting with CsF, the sample is cooled and immersed in 0.1 N HCl solution to remove the CsF coating. After drying, a AlAs wafer having a clean oxide free surface is obtained. This work was done under NASA Contract NAS12-2169.

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