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Flow field velocity measurements for non-isothermal systemsExperimental techniques which can be potentially utilized to measure the gas velocity fields in nonisothermal CVD systems both in ground-based and space-based investigations are considered. The advantages and disadvantages of a three-component laser velocimetry (LV) system that was adapted specifically for quantitative determination of the mixed convective flows in a chamber for crystal growth and film formation by CVD are discussed. Data from a horizontal research CVD reactor indicate that current models for the effects of thermophoretic force are not adequate to predict the thermophoretic bias in arbitrary flow configurations. It is concluded that LV techniques are capable of characterizing the fluid dynamics of a CVD reactor at typical growth temperatures. Thermal effects are shown to dominate and stabilize the fluid dynamics of the reactor. Heating of the susceptor increases the gas velocities parallel to the face of a slanted susceptor by up to a factor of five.
Document ID
19930049072
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Johnson, E. J.
(NASA Langley Research Center Hampton, VA, United States)
Hyer, P. V.
(NASA Langley Research Center Hampton, VA, United States)
Culotta, P. W.
(NASA Langley Research Center Hampton, VA, United States)
Clark, I. O.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1991
Publication Information
Publication: In: Crystal growth in space and related optical diagnostics; Proceedings of the Meeting, San Diego, CA, July 22, 23, 1991 (A93-33051 12-29)
Publisher: Society of Photo-Optical Instrumentation Engineers
Subject Category
Materials Processing
Accession Number
93A33069
Distribution Limits
Public
Copyright
Other

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