MODELING OF GROWTH-RATE UNIFORMITY OF CDTE EPILAYER BY MOCVD

A 2-dimensional mathematical model was established to simulate the growth rate uniformity of CdTe epilayers which were grown in a horizontal MOCVD reactor. Both transport phenomena and the surface decomposition kinetics of diethyl telluride were considered. The calculated effects of reactor pressure and substrate temperature on growth rates along the flow axis were compared with experimental results. They agreed well with each other. These effects were then explained by the relative importance of mass transfer to reaction kinetics. In general, higher growth temperature and higher reactor pressure both favor a mass transfer controlled CVD growth situation. However, to obtain uniformly grown epilayers, one would wish to operate under reaction kinetics controlled region, i.e. low substrate temperature and low reactor pressure.