Browse Prior Art Database

Coated Graphite Susceptor

IP.com Disclosure Number: IPCOM000092950D
Original Publication Date: 1967-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Doo, VY: AUTHOR

Abstract

This graphite susceptor is coated with molybdenum silicide to prevent outgasing of residual impurities in the graphite at elevated temperatures during pyrolytic processes. Molybdenum silicide is stable and chemically inert at elevated temperatures.

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Coated Graphite Susceptor

This graphite susceptor is coated with molybdenum silicide to prevent outgasing of residual impurities in the graphite at elevated temperatures during pyrolytic processes. Molybdenum silicide is stable and chemically inert at elevated temperatures.

Graphite susceptors are widely used in silicon epitaxial growth and other pyrolytic reactors. Graphite is usually porous after machining and its surface is unsmooth. During heating, some residual impurities in the graphite gradually diffuse out to contaminate the silicon epitaxial and other growth processes. Graphite with a thin layer of high-temperature material, chemically inert, prevents any out-diffusion of the trapped impurities.

Molybdenum silicide is applied to a graphite susceptor by first coating a layer of silicon dioxide or other refractory materials, such as aluminum oxide or nitride, on the graphite by conventional processes. The layer provides a smooth surface for the graphite and is usually of the order of .5 - 1 micron in thickness. Then, successive thin layers of molybdenum metal and silicon are deposited on the susceptor. The molybdenum metal is of the order of .8 - 1.2 micron in thickness. The silicon is of the order of .8 - 1.2 micron in thickness. Conventional processes are employed for such deposition. The susceptor is heated to 1200 degrees C for one-half to one hour to promote the formation of molybdenum silicide.

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