Epitaxial growth of GaN on β-Ga2O3 via RF plasma nitridation

The lack of suitable p-type dopant for β-Ga2O3 remains a hurdle for vertical power device applications. Epitaxy of GaN on Ga2O3 substrates was demonstrated as an alternative. (–201)-oriented β-Ga2O3 was converted into (0001)-oriented hexagonal GaN via nitrogen plasma in a plasma-assisted molecular beam epitaxy chamber, as verified by XRD and RHEED. The resulting nitridated GaN layers were characterized by TEM, x-ray reflectivity, and AFM to relate the nitridation conditions to crystallinity, layer thickness, and surface roughness. The crystallinity of subsequently grown epitaxial GaN films was quantified via XRD rocking curves and related to the nitridation layer properties across varying nitridation conditions. Specifically, the effect of the grain size and nitridation layer thickness was investigated to determine their role in threading screw dislocation management.