KINETIC-STUDY OF METALORGANIC MOLECULAR-BEAM EPITAXY OF GAP, INP, AND GAXIN1-XP

The growth rates of GaP and InP deposited by metalorganic molecular beam epitaxy using triethylgallium, trimethylindium, and precracked phosphine have been studied by reflection high energy electron diffraction and related to composition variations of the ternary alloy Ga(x)In(1-x)P. The influence of the substrate temperature and phosphine flow rate have been investigated for each material. The GaP growth rate dependence with temperature exhibits qualitatively the same behavior as already reported for the growth of GaAs by metalorganic molecular beam epitaxy. In the case of InP, a constant growth rate is observed in the temperature range of 450-500-degrees-C. At higher temperatures, a strong decrease of the growth rate, attributed to the desorption of dimethylindium species, is measured. Meanwhile, the Ga(x)In(1-x)P composition is found to become Ga rich while increasing temperature. Furthermore, it is found to significantly depend on the phosphine flow rate at a fixed temperature. In the low phosphine flow regime, the composition is associated with the preferential formation of GaP bonds, and in the high phosphine flow regime, the composition is closely correlated with the sharp decrease observed for the binary InP growth rate.