SIMS investigations into the effect of growth conditions on residual impurity and silicon incorporation in GaN and AlxGa1-xN

We have investigated the effect of metal-organic chemical vapour deposition growth conditions on impurity incorporation in GaN and AlGaN. Secondary ion mass spectrometry depth profile analyses were performed on GaN and AlGaN wafers with multiple layers in which temperature, V/III ratio, growth rate, carrier gas, Al content, and Si doping were varied. Trends in oxygen, carbon, and silicon concentrations were studied. Similar trends were observed for both GaN and AlGaN. Growth temperature, composition and V/III ratio had the largest effect on impurity incorporation. Silicon and oxygen incorporation were less susceptible to growth conditions than that of carbon.