Temperature dependence of electrical characteristics of Si-implanted AlN layers on sapphire substrates

AlN with a large bandgap energy is one of the most attractive materials for high-temperature applications. However, performance of AlN devices at high temperatures has been limited by technical problems with electrical characterization systems. Here, we show that Schottky-barrier diodes (SBDs) and metal-semiconductor field-effect transistors with Si-implanted AlN channels can operate at 1100 K and 1000 K, respectively. The breakdown voltage and barrier height of the AlN SBD were 610 V and 3.5 eV, respectively. We found that the high barrier height and thermal stability of the Ni contact on AlN greatly contributed to high-temperature operation of the devices.