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Chemical Vapor Deposition Growth of Single Crystal Garnet Films

IP.com Disclosure Number: IPCOM000080194D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Cowher, ME: AUTHOR [+2]

Abstract

A method has been devised for growing, by chemical vapor deposition, single crystal garnet films using organometallic compounds. Preferred organometallic compounds are the 2,2,6,6 tetramethylheptanedionates (thd).

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Chemical Vapor Deposition Growth of Single Crystal Garnet Films

A method has been devised for growing, by chemical vapor deposition, single crystal garnet films using organometallic compounds. Preferred organometallic compounds are the 2,2,6,6 tetramethylheptanedionates (thd).

In inorganic chemical vapor deposition (CVD) processes for magnetic bubble garnet growth, the difficult to volatilize, rare earth elements are vaporized in an inert carrier gas as halides using rare earth halide vapor pressure sources at high temperatures, ca. 1000 degrees C, requiring large cumbersome resistance heated furnaces. These gases are then combined with an iron halide vapor (and sometimes a gallium halide vapor), and then finally mixed with oxygen or water vapor just before the deposition zone where an extremely rapid reaction occurs to deposit solid films of garnet, orthoferrite, or other compounds.

This inorganic process produces garnet films with nonuniformities (dust like inclusions, nonuniform thickness, growth rate and stoichiometry variations), which are due at least partly to the extremely high reactivity of oxygen or water with the halides. For example, the presence of moisture during loading of the source boats or of traces of H(2)O or O(2) in the inert carrier gas passing through the sources at high temperatures, results in a reaction on the surface of the halide source materials which reduces the vaporization rate, and subsequently the film growth rate or stoichiometry in an unknown or irreproducible way. Also the rapid rate of reaction between the halide reactants and oxygen at elevated temperatures in the deposition region, makes it difficult to mix the reacting gases together sufficiently to obtain a uniform film deposited over a wide area while avoiding prereaction to form dust particles.

In general, many CVD source reactants including organometallic compounds such as the commonly used alkyls, isopropoxides and acetyl acetonates exhibit a similar high reactivity with O(2) and or H(2)O, which requires ultracareful handling of reactants and purification of inert carrier gases. Although many organometallic complexes are much...