Oxygen Incorporation in the Molecular Beam Epitaxy Growth of ScxGa1-xN and ScxAl1-xN

Secondary-ion mass spectrometry (SIMS) is used to determine impurity concentrations of carbon and oxygen in two scandium-containing nitride semiconductor multilayer heterostructures: ScxGa1-xN/GaN and ScxAl1-xN/AlN grown by molecular beam epitaxy (MBE). In the ScxGa1-xN/GaN heterostructure grown in metal-rich conditions on GaN-SiC template substrates with Sc contents up to 28 at%, the oxygen concentration is found to be below 1 x 10(19) cm(-3), with an increase directly correlated with the scandium content. In the ScxAl1-xN-AlN heterostructure grown in nitrogen-rich conditions on AlN-Al2O3 template substrates with Sc contents up to 26 at%, the oxygen concentration is found to be between 10(19) and 10(21) cm(-3), again directly correlated with the Sc content. The increase in oxygen and carbon takes place during the deposition of scandium-alloyed layers.