Modeling of gas curtains in a dual chamber hydride vapor phase epitaxial photovoltaic growth reactor

Hydride vapor phase epitaxy (HVPE) is a low-cost method for the deposition of high-efficiency III-V photovoltaics. HVPE offers the use of lower cost reagents and high growth rates, both of which reduce cost compared to metalorganic vapor phase epitaxy (MOVPE) while maintaining high performance. Our dual chamber reactor design with gas curtain separation facilitates the formation of abrupt interfaces and monolithic integration of multiple materials chemistries. This reactor has a more complex flow profile compared to single chamber designs, requiring more intensive flow optimization. Experimental optimization alone is not enough to develop a deep understanding of the factors affecting the gas composition profile in the reactor. Computational fluid dynamics (CFD) modeling is a vital tool that provides insight into the design and operation of VPE reactors. This work presents the use of a commercial software package to model a case study in our custom HVPE reactor. The effect of the “curtain” gas species identity on cross contamination between the growth chambers is examined in detail. It was found that use of a heavier curtain gas alone is not sufficient to reduce cross contamination. CFD modeling determined the flow for a given gas must be balanced to minimize the development of horizontal flows and eddy currents in order to minimize cross contamination.