Growth, doping and characterization of AlxGa1-xN thin film alloys on 6H-SiC(0001) substrates

Thin films of AlxGa1-xN (0.05 less than or equal to x less than or equal to 0.96) having smooth surfaces were deposited directly on both vicinal and on-axis 6H-SiC(0001) substrates. Cross-sectional transmission electron microscopy of Al0.13Ga0.87N revealed stacking faults near the SiC/nitride alloy interface and numerous threading dislocations. Energy dispersive analysis, Auger electron spectroscopy (AES) and Rutherford backscattering were used to determine the compositions. These were paired with their respective cathodoluminescence (CL) near band-edge emission energies. A negative bowing parameter was determined. The CL emission energies were similar to the bandgap energies obtained by spectroscopic ellipsometry. Field emission AES of the initial growth of Al0.2Ga0.8N revealed an Al-rich layer near the interface. N-type (Si) doping was achieved for AlxGa1-xN for 0.12 less than or equal to x less than or equal to 0.42. (C) 1997 Elsevier Science S.A.