Analysis of Schottky Forward Current Transport Mechanisms in AlGaN /GaN HEMTs over a Wide Temperature Range

The current transport mechanisms of Ni/Au/Ni schottky contact in AlGaN/GaN high electron mobility transistors are investigated from room temperature to 473 K combined experiments and numerical simulations. The ideality factor extracted by the forward schottky characteristics is temperature sensitive and far from the value which the ideal contact should has. To have a deep understanding of the real transport behavior, both the experimental results in room temperature and 473 K are fitted by the four transport mechanisms possible in the Schottky contact using numerical simulations with the schottky series resistance involved. And it can be found that the thermionic emission current portion increases at high temperature, while the dominant mechanism is still the tunneling current assisted by dislocations both at room temperature and 473 K.