Dislocation-Related Electron Transport in Au Schottky Junctions on AlGaN/GaN
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We investigated the electrical properties of Au/AlGaN/GaN Schottky junctions as a function of temperature by analyzing the current–voltage (I–V) measurements. The barrier height increased with increasing temperature, but the ideality factor decreased. Increases in temperature are associated with barrier inhomogeneity. The modified Richardson plots for Al0.25Ga0.75N yielded a higher Richardson constant, 77.3 A cm−2K−2, than theoretically predicted (30.0 A cm−2 K−2). This indicates that the thermionic emission (TE) model with barrier inhomogeneity is not suitable for explaining the transport characteristics of the junction. We fitted the experimental I–V data to predictions based on various transport mechanisms, such as TE, generation-recombination, and tunneling currents. The dominant transport mechanism at all temperatures was found to be caused by the tunneling current. The dislocation model of the tunneling current yielded a dislocation density of 2.96 × 106 cm−2.
KeywordsAlGaN/GaN Tunneling current Dislocation density
This research was supported in part by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A1B03030400).