Thermodynamic analysis of III-V semiconductor alloys grown by metalorganic vapor phase epitaxy

Thermodynamic analysis of III-V semiconductor alloys grown by metalorganic vapor phase epitaxy Toshihiro Asai and David S. Dandy Dept. of Chemical Engineering, Colorado State University, Fort Collins, Colorado 80523-1370 A thermodynamic analysis has been applied to systematically study III-V semiconductor alloy deposition, including nitrides grown by metalorganic vapor phase epitaxy. The predicted solid compositions of a number of ternary and quaternary alloys, including AlxGa1-xPyAs1-y, are compared with experimental data. For phosphorous-containing alloys, introduction of a parameter f representing incomplete PH3 pyrolysis yields good agreement with experimental data. It is shown that the input mole fraction of the group III metalorganic sources influences the incorporation of P into the solid for these alloys. Solid composition is also calculated for nitride alloys as a function of inlet gas concentration. To date, thermodynamic models have been applied solely to predict N solubility limits for nitride alloys where mixing occurs on the group V sublattice. The present model is used to predict N solid compositions in ternary and quaternary alloys, and it is demonstrated that these values are below the theoretical solubility limits for In-containing nitrides. The role of H2 in the carrier gas is investigated for III-N-V, III-III-N-V, and III-N-V-V systems.