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

A thermodynamic analysis has been applied to systematically study III-V sem iconductor 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 experiment al data. For phosphorus-containing alloys, introduction of a parameter f re presenting incomplete PH3 pyrolysis yields good agreement with experimental data. It is shown that the input mole fraction of the group III metalorgan ic sources influences the incorporation of P into the solid for these alloy s. Solid composition is also calculated for nitride alloys as a function of inlet gas concentration. To date, thermodynamic models have been applied s olely 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 co mpositions in ternary and quaternary alloys, and it is demonstrated that th ese values are below the theoretical solubility limits for In-containing ni trides. The role of H-2 in the carrier gas is investigated for III-N-V, III -III-N-V, and III-N-V-V systems. (C) 2000 American Institute of Physics. [S 0021-8979(00)03520-9].