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A Comprehensive Model of the Growth of Cadmium Zinc Telluride (CZT) by the Traveling Heater Method (THM)

Jeff H. Peterson ,  Andrew Yeckel ,  Jeffrey J. Derby 

University of Minnesota, Chemical Engineering and Materials Science, 421 Washington Ave. S.E., Minneapolis, MN 55455, United States

Abstract

The traveling heater method (THM) has enjoyed particular success for the growth of cadmium telluride (CdTe) and cadmium zinc telluride (CZT).  Unlike in conventional melt growth, THM material is grown via a different path on its phase diagram, notably from a liquid solvent phase that contains excess tellurium. This solvent phase is produced in a liquid zone that is moved (via a traveling heater) past a charge of CdTe or CZT. Desirable attributes of THM include lower growth temperatures and material that contains less excess tellurium than material grown from the melt.  However, growth rates in THM are typically orders of magnitude less than in melt growth processes.

THM is inherently more complicated than melt growth methods, since compositional effects, including both phase equilibria and phase change kinetics, are of paramount importance.  Hence, our fundamental understanding of THM is limited in comparison.  In this presentation, we formulate a comprehensive mathematical model for this process, along with rigorous phase diagram information, using the framework of our prior crystal growth models that account for heat and species transfer, fluid mechanics, and moving, phase-change interfaces.  We then summarize the finite element methods employed for solution of this model and present initial results.

Our objective is to study and understand THM growth characteristics, such as interface shape, thermal gradients, interfacial stability, and crystal composition (both tellurium excess and zinc distribution).  In particular, we will examine parametric process sensitivity to factors such as growth rate, heater profile, and size of the melt zone. In particular, we examine phenomena that limit achievable growth rates in this system, such as constitutional supercooling, growth kinetics, and dissolution rates of the feed into the zone.

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Supported in part by U.S. National Science Foundation, NSF DMR-1007885, the content of which does not necessarily reflect the position or policy of the United States Government, and no official endorsement should be inferred.

 

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Related papers

Presentation: Poster at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 4, by Jeffrey J. Derby
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17

Submitted: 2013-03-27 18:14
Revised:   2013-05-31 22:04