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Preparation of Garnet Single Crystal Surfaces for Epitaxy

IP.com Disclosure Number: IPCOM000077204D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Giess, EA: AUTHOR [+3]

Abstract

A technique is described for optimization of a chemical-mechanical polishing step, to obtain high quality (low defect content) garnet substrates for epitaxial growth of garnet films.

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Preparation of Garnet Single Crystal Surfaces for Epitaxy

A technique is described for optimization of a chemical-mechanical polishing step, to obtain high quality (low defect content) garnet substrates for epitaxial growth of garnet films.

A problem in the preparation of high quality epitaxial garnet films is the realization of strain-free substrate surfaces suitable for film growth. Surface strains in the substrate yield epitaxial films with unfavorable domain characteristics. A four step chemical- mechanical polishing scheme is described to obtain routinely garnet substrates of excellent topographical quality.

A sliced wafer from a Czochralski grown boule whose nominal orientation is (111) is the starting point. The first three steps consist of polishing with 30 micron, 9 micron and 3 micron diamond grits. The 30 micron polishing was done in kerosene base, whereas others were polished in water base. Generally, the stock removed in individual steps was about three times the size of the grit used in the previous step. Diamond finished surfaces had the typical crisscross pattern of micro and macroscratches. The defect density was the highest at the periphery.

In the final step SYTON* was used as the chemical mechanical agent to remove the surface strains caused by mechanical polishing with diamond. The SYTON polishing on resin-bonded nonwoven fabric is a step in obtaining useful surfaces for epitaxy. Some of the factors in the SYTON polishing of garnet wafers are described below: A. Temperature o...