Effect of rapid thermal annealing on radio-frequency magnetron-sputtered GaN thin films and Au/GaN Schottky diodes

The structural and optical properties of rf magnetron-sputtered GaN thin fi lms on p(+)-Si substrates have been accessed as a function of rapid thermal annealing (RTA) temperatures from 800 to 1000 degrees C. The evidence has revealed that higher RTA temperatures not only assist the GaN films in recr ystallizing into stable hexagonal form but also enhance the near-band-edge emission of GaN films in the photoluminescence spectrum. Moreover, a deep e lectron trap (E-t) with activation energy E-c-E(t)congruent to 0.39 eV dete cted at the surface of higher-RTA-temperature-treated GaN films was asserte d to be a nitrogen-vacancy-related defect that takes a defect-assisted-tunn eling role in the forward conduction process of Au/GaN Schottky diode. The greater reverse leakage current and lower breakdown voltage are suggested t o be due to the effects of a lower barrier height and higher ideality facto r that occurred in the higher-RTA-temperature-treated samples. (C) 1999 Ame rican Vacuum Society. [S0734-211X(99)02504-4].