Oxygen Incorporation in the Molecular Beam Epitaxy Growth of Sc_xGa_1−xN and Sc_xAl_1−xN

Abstract

Secondary‐ion mass spectrometry (SIMS) is used to determine impurity concentrations of carbon and oxygen in two scandium‐containing nitride semiconductor multilayer heterostructures: Sc x Ga 1− x N/GaN and Sc x Al 1− x N/AlN grown by molecular beam epitaxy (MBE). In the Sc x Ga 1− x N/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 × 10 19 cm −3 , with an increase directly correlated with the scandium content. In the Sc x Al 1− x N–AlN heterostructure grown in nitrogen‐rich conditions on AlN–Al 2 O 3 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.