Tunneling current via dislocations in Schottky diodes on AlInN/AlN/GaN heterostructures
The forward current-voltage-temperature characteristics of (Ni/Au)-Al 0.83In0.17N/AlN/GaN heterostructures were studied in a temperature range of 80-375 K. The temperature dependences of the tunneling saturation current (It) and tunneling parameters (E0) were obtained. Weak temperature dependence of the saturation current and the absence of temperature dependence of the tunneling parameters were observed in this temperature range. The results indicate that in the temperature range of 80-375 K, the mechanism of charge transport in the (Ni/Au)-Al0.83In 0.17N/AlN/GaN heterostructure is performed by tunneling among dislocations intersecting the space-charge region. A model is used for nonuniform tunneling along these dislocations that intersect the space-charge region. The dislocation density that was calculated from the current-voltage characteristics, according to a model of tunneling along the dislocation line, gives the value 7.4 × 108 cm-2. This value is close in magnitude to the dislocation density that was obtained from the x-ray diffraction measurements value of 5.9 × 108 cm-2. These data show that the current flows manifest a tunneling character, even at room temperature.