Influence of gallium sources on carbon incorporation efficiency into InGaAs grown by metalorganic chemical vapor deposition

Carbon incorporation into InGaAs has been systematically investigated using trimethylgallium (TMGa) and triethylgallium (TEGa) as gallium sources. Although the hole concentrations decrease with increasing In composition, the hole concentrations in layers grown with TMGa are found to be several times higher than those grown with TEGa. From Hall and secondary ion mass spectroscopy measurements, the hole concentration decrease with increasing In composition is revealed to be due to a decrease in the efficiency of C incorporation into InGaAs. Based on a numerical analysis where it was assumed the In atoms enhance the C source dissociation from the substrate surface, the higher surface step density in the kinetically limited growth mode region is proposed as the essential reason for the higher C incorporation efficiency into InGaAs grown with TMGa. This model is experimentally confirmed by the atomic force microscope observation and comparing higher surface step density substrates.