US Government As Represented by the Secretary of the Army

Barbara E Sumner

Phillip R Boyd

Gary K Green

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.

Method of preparing a mercury cadium telluride substrate for passivation

A crystal substrate of &lt;111&gt; silicon is doped by being exposed to a liquid etal solvent. The substrate is carried in a cavity in a refractory boat, and the solvent is carried in a perforation of a cover for the boat. The boat is heated to a certain temperature in a non-oxidizing atmosphere and is moved to place the substrate cavity under the cover perforation whereby the solvent and substrate come in contact. The temperature is raised and held to allow the desired substrate-solvent solution to form, then is reduced and held to allow supersaturation and eventually precipitation of the doped substrate. The boat is next moved to remove the cavity from beneath the perforation, is allowed to cool to room ambient, and is removed from the non-oxidizing atmosphere. The doped substrate is then cleaned as desired to remove any attached solvent.

Method for making epitaxial silicon crystals with uniform doping levels

An ultra high resolution screen is provided by spraying small phosphor pacles onto a rotating disc-shaped substrate coated with a thermoplastic film heated to its softening point.

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Alexandria, VA, United States of America

Barbara E Sumner