Process for forming epitaxial BaF.sub.2 on GaAs
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsFrancisco Santiago, Tak-Kin Chu, Michael Stumborg
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Abstract
A process for growing single crystal epitaxial BaF.sub.2 layers on gallium rsenide substrates by slowly reacting Ba, BaCl.sub.2, Bal.sub.2, BaBr.sub.2, BaF.sub.2 .cndot.BaCl.sub.2, BaF.sub.2 .cndot.BaBr.sub.2, BaF.sub.2 .cndot.BaI.sub.2, BaCl.sub.2 .cndot.BaBr.sub.2, Ba.sub.3 (GaF.sub.6).sub.2, BAH.sub.2, or BaO.sub.2 vapor with a clean, hot GaAs substrate at 500.degree. C. to 700.degree. C. in high vacuum until a uniform, thin (.about.12 .ANG.) layer of reaction product is formed and then vapor depositing BaF.sub.2 onto the reaction layer at room temperature to 400.degree. C. to form the single crystal, epitaxial BaF.sub.2 layer.
Claims32
A process for forming a uniform, single, crystal, epitaxial layer of barium fluoride on a single crystal gallium arsenide substrate comprising:
- A. vapor depositing barium on a clean, hot single crystal gallium arsenide substrate at a temperature of from 500.degree. C. to 700.degree. C., in a vacuum having a background pressure of 10.sup.-8 millibars or less and wherein the barium deposition is slow enough to allow the barium vapor to react with the gallium arsenide substrate surface and form a uniform, epitaxial coating of barium/gallium arsenide reaction product and continuing until the reaction product layer is completed;
- B. heating the barium/gallium arsenide reaction product layer at a temperature of from 500.degree. C. to 700.degree. C. in the absence of barium vapor in a vacuum having a background pressure of 10.sup.-8 millibars or less to remove unreacted barium;
- and then
- C. reducing the temperature of the substrate to a temperature of from room temperature to a temperature less than 700.degree. C. and depositing barium fluoride at a rate of from 1 to 100 .ANG. per minute until the desired thickness of uniform, single crystal, epitaxial barium fluoride has been achieved.
A process for forming a uniform, single, crystal, epitaxial layer of barium fluoride on a single crystal gallium arsenide substrate comprising
- A. vapor depositing a barium compound that is barium chloride, barium iodide, barium bromide, barium fluochloride, barium fluobromide, barium fluoiodide, barium chlorobromide, barium fluorogallate, barium hydride, or barium peroxide on a clean, hot single crystal gallium arsenide substrate at a temperature of from 500.degree. C. to 700.degree. C., in a vacuum having a background pressure of 10.sup.-8 millibars or less and wherein the barium compound deposition is slow enough to allow the barium compound vapor to react with the gallium arsenide substrate surface and form a uniform, epitaxial coating of barium compound/gallium arsenide reaction product and continuing until the reaction product layer is completed;
- B. heating the barium compound/gallium arsenide reaction product layer at a temperature of from 500.degree. C. to 700.degree. C. in the absence of the barium compound vapor in a vacuum having a background pressure of 10.sup.-8 millibars or less to remove unreacted barium compound;
- and then
- C. heating the substrate at temperature of from room temperature to 700.degree. C. and depositing barium fluoride at a rate of from 1 to 100 .ANG.per minute until the desired thickness of uniform, single crystal, epitaxial barium fluoride has been achieved.
Dependencies are inferred from the claim text.