Transport properties and barrier height evaluation in Ni/InAlN/GaN Schottky diodes

Abstract

The current-voltage characteristics of the Ni/InAlN/GaN Schottky diodes were measured at various temperatures in the range of 300–820 K. The experimental data were analyzed considering different current-transport mechanisms, such as thermionic emission, generation-recombination, tunneling and leakage currents. From the fitting of experimental data it follows that the tunneling current dominates in whole temperature range. The thermionic emission becomes comparable to the tunneling current only at highest temperatures used. The barrier height of the Ni/InAlN/GaN Schottky diodes, evaluated from the thermionic emission current, shows a slightly negative temperature coefficient and its value at 300 K is 1.47 eV. Lower barrier heights were reported before, which follow from an incorrect evaluation of measured data without separation of individual current components. The dislocation density of about 2×109 cm−2 is obtained assuming dislocation governed tunneling current mechanism.