Pyrolysis Effect of Group V Vapor Sources on the Composition Ranges for Metal-Organic Vapor Phase Epitaxy Growth of III-V Semiconductors

摘要

The pyrolysis effect of NH_3 and PH_3 vapor sources on the composition ranges necessary for growing single-phase semiconductors was studied with respect to the metal-organic vapor phase epitaxy (MOVPE) of GaN and (Ga_(1-x)In_x)P semiconductors. The Ga-N-C-H system and the Ga-In-P-C-H system were thermodynamically analyzed respectively under the conditions of the equilibrium pyrolysis, the partial pyrolysis, and the non-pyrolysis of the vapor phase species, NH_3 and PH_3. Both the complete equilibrium and the constraint equilibrium in these two systems were calculated with the aid of the specially designed database files and Thermo-Calc software. The experimental MOVPE data from the literature were compared with calculated results. The correspondence of the theoretical prediction with the experimental data indicates that the thermodynamic analysis for the MOVPE process of GaN and (Ga_(1-x)In_x)P semiconductors needs to be considered in terms of the practical pyrolysis of NH_3 and PH_3 vapor sources. The approach of the complete thermodynamic equilibrium is applied only to some specific temperature region or certain epitaxy processes after typical pretreatment of vapor sources.