GROWTH OF MgCaO ON GaN

摘要

The feasibility of depositing ternary oxides on GaN has been investigated. MgCaO films were deposited by gas-source molecular beam epitaxy using elemental metals and a radio frequency oxygen plasma. Films deposited with roughly equal Mg and Ca beam equivalent pressures showed disproportionately high Mg/Ca ratios, indicative of a low Ca sticking coefficient. Depth profiling Auger electron spectroscopy (AES) showed a steep increase in the Ca concentration at the surface relative to the oxide/GaN interface. This segregation was enhanced at lower growth rate. In spite of this segregation, XRD of films deposited at 100℃ showed no evidence of phase separation. The addition of Ca did appear to increase the lattice constant of the material thus reducing the mismatch to GaN.