Study of growth conditions effect on GaN doping with carbon from propane and methane

A comprehensive study of intentional GaN carbon doping from propane and methane during MOVPE was performed in a wide range of growth conditions using both hydrogen and nitrogen carrier gas with growth rate varies from 0.8 to 62 $\mu$m/h. Carbon concentration raise with growth rate was revealed both precursors. For the same conditions carbon incorporation from methane is about one order lower than from propane. However, methane produced by trimethylgallium pyrolysis was revealed to be an important source for background carbon incorporation, especially at high growth rate. Character of the dependencies of carbon incorporation on concentration of carbon precursor and ammonia is significantly different for nitrogen and hydrogen carrier gases. Temperature dependencies of carbon incorporation from methane and background incorporation are similar while propane is more effective precursor at high temperature.