Electrical characteristics and carrier transport mechanism for Ti/ p -GaN Schottky diodes

The temperature dependence of the electrical characteristics of non-alloyed Ti/ p -GaN Schottky diodes was examined using current-voltage-temperature, turn-on voltage-temperature, and series resistance-temperature measurements. The thermal coefficient ( K j ) and characteristic temperature ( T 0 ) at T ≥ 293 K were determined to be −4.1 mV/K and 65.06 K, respectively. The effective Schottky barrier height (SBH) was also determined to be 2.1 (±0.03) eV, which was in good agreement with the theoretical value. The possible carrier transport mechanisms at the interface are described in terms of the thermally decreased energy-band gap of p -GaN layers, thermally increased deep-level acceptor and increased further-activated-shallow-level acceptor. These were confirmed by the thermally increased ideality factor and high tunnelling parameter.