  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 atomic percent, the oxygen concentration is found to be below
1x1019/cm3, 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 atomic percent, the
oxygen concentration is found to be between 1019 to 1021/cm3, again directly
correlated with the Sc content. The increased oxygen and carbon arises during
the deposition of scandium alloyed layers.
