US Government As Represented by the Secretary of the Army

Gary K Green

Barbara E Sumner

Phillip R Boyd

A method of preparing a mercury cadmium telluride substrate with a cadmium elluride surface of less than 200 .ANG. to yield a surface exhibiting improved quality and smaller variation in the x-valve of a Hg.sub.1-x Cd.sub.x Te substrate for passivation and processing of the CdTe processed surface. The method comprises the steps of etching said Hg.sub.1-x Cd.sub.x Te substrate with a bromine methanol or bromine-DMF etch, quenching the substrate in methanol or DMF until the bromine is removed and rinsing in acetone and methanol to remove soluble residuals and drying immediately, coating said substrate with CdTe layer of about 1000 .ANG., polishing the processed CdTe layer by a contactless polishing means using a polishing solution of 50% ethylene glycol and 50% mixture of 2% bromine and 98% methanol wherein said CdTe layer is polished down to generally less than 200 .ANG. according the monitored condition of the CdTe layer, and repeating the quenching, rinsing and drying steps to remove all bromine and soluble residuals.

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Fredericksburg, VA, United States of America

Gary K Green