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Modeling and Real-Time Process Monitoring of Organometallic Chemical Vapor Deposition of III-V Phosphides and Nitrides at Low and High PressureThe purpose of this paper is to review modeling and real-time monitoring by robust methods of reflectance spectroscopy of organometallic chemical vapor deposition (OMCVD) processes in extreme regimes of pressure. The merits of p-polarized reflectance spectroscopy under the conditions of chemical beam epitaxy (CBE) and of internal transmission spectroscopy and principal angle spectroscopy at high pressure are assessed. In order to extend OMCVD to materials that exhibit large thermal decomposition pressure at their optimum growth temperature we have designed and built a differentially-pressure-controlled (DCP) OMCVD reactor for use at pressures greater than or equal to 6 atm. We also describe a compact hard-shell (CHS) reactor for extending the pressure range to 100 atm. At such very high pressure the decomposition of source vapors occurs in the vapor phase, and is coupled to flow dynamics and transport. Rate constants for homogeneous gas phase reactions can be predicted based on a combination of first principles and semi-empirical calculations. The pressure dependence of unimolecular rate constants is described by RRKM theory, but requires variational and anharmonicity corrections not included in presently available calculations with the exception of ammonia decomposition. Commercial codes that include chemical reactions and transport exist, but do not adequately cover at present the kinetics of heteroepitaxial crystal growth.
Document ID
19990078569
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Bachmann, K. J.
(North Carolina State Univ. Raleigh, NC United States)
Cardelino, B. H.
(Spelman Coll. Atlanta, GA United States)
Moore, C. E.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Cardelino, C. A.
(Georgia Inst. of Tech. Atlanta, GA United States)
Sukidi, N.
(North Carolina State Univ. Raleigh, NC United States)
McCall, S.
(North Carolina State Univ. Raleigh, NC United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1999
Subject Category
Inorganic And Physical Chemistry
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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