(28d) Modeling and Analysis of Rapid Synthesis of GaAs By Hydride Vapor Phase Epitaxy Process

Photovoltaic devices fabricated by III-V semiconductor materials have demonstrated exceptional efficiencies of harnessing solar energy typically in concentrator systems. However, III-V solar cells could also be cost competitive if industrially viable growth systems characterized by high growth rate and excellent product performance (high film uniformity, low defect densities, etc.) are developed and combined with an epitaxial removal technology. Hydride vapor phase epitaxy (HVPE) has been demonstrated to provide high quality III-V semiconductors in a cost-effective way. Compared with metalorganic vapor phase epitaxy (MOVPE) processes, HVPE has a significantly higher growth rate and requires no expensive metal-organic precursors [1, 2, 3]. But before the application of HVPE for photovoltaics, it must be proved that solar cell quality materials could be produced at high growth rate by this method.

We have developed a HVPE system that is capable of growing III-V semiconductor materials, such as GaAs and GaInP, at high growth rate with controlled formation of pn junctions [1]. To clarify underlying relationships between process parameters and product properties, model-based method is further employed. In this presentation, we will focus on demonstrating numerical modeling of transport phenomena in HVPE reactor for GaAs growth. In this model, we have coupled temperature-dependent reaction kinetics with fluid mechanics and reactor geometry. Simulation results calculated by finite element techniques are correlated with experimental data to verify this model. Based on the quantitative investigation of the influence of reactor geometry and process parameters on flow pattern, temperature distribution, growth rate and film uniformity, optimal design parameter regions that achieving the process objectives of maximizing reactive efficiencies of the feed gas and maximizing film spatial uniformity will be identified. It is expected that the progress of this work will facilitate the development of novel high-throughput rapid-growth HVPE system for energy application.

References

[1] K. L. Schulte, W. L. Rance, R. C. Reedy, A. J. Ptak, D. L. Young, T. F. Kuech. Controlled formation of GaAs pn junctions during hydride vapor phase epitaxy of GaAs. Journal of Crystal Growth. 352(1): 253-257 (2012).

[2] K. Matsumoto, H. Tokunaga, A. Ubukata, K. Ikenaga,Y. Fukuda, Y. Yano, et al. High growth rate MOVPE . Springer Series in Materials Science: Technology of Gallium Nitride Crystal Growth. 133: 119-133 (2010).

[3] C. Lynch, D. F. Bliss, T. Zens, A. Lin, J. S. Harris, P. S. Kuo, M. M. Fejer. Growth of mm-thick orientation-patterned GaAs for IR and THZ generation. Journal of Crystal Growth, 310: 5241-5247 (2008).