Temperature dependent high frequency performance of a 62% AlGaN channel HEMT

This article reports on the temperature dependent performance of a HEMT with an Al0.62Ga0.38N channel layer and an Al0.84Ga0.16N barrier layer grown by metal–organic chemical vapor deposition. The device in this report was measured at room temperature and elevated temperatures of 100–150 °C. The sheet resistance increased from 3.5 kΩ/sq (25 °C) to 5.4 kΩ/sq (150 °C), while the contact resistance remained nominally similar. For a device with 160 nm gate length and 2 μm source-to-drain length, excellent electrical characteristics have been achieved when the device was operated at 150 °C with a fT of 17 GHz and a fmax of 25.6 GHz. The reported device also exhibited outstanding gate leakage control, where <1 μA/mm was measured up to 150 °C. A high breakdown voltage (up to 280 V) was also obtained at room temperature, indicating good high-power capabilities. This report is also the first to demonstrate high temperature DC and RF performances on a >60% Al composition AlGaN channel HEMT, which suggests the great potential of AlGaN channel devices for high frequency, high power, high temperature applications.