High‐speed and low‐noise AlInN/GaN HEMTs on SiC

A comparison of devices with different source–drain gaps has been performed on AlInN/GaN high electron mobility transistors (HEMTs) grown on SiC. The cut‐off frequency is effectively improved through shrinking source drain space and reducing gate parasitic capacitance. Our devices feature an f T of 188 GHz and f MAX of 200 GHz, which is the highest f MAX ever achieved to date for AlInN‐based HEMTs. At 10 (20) GHz, our HEMTs exhibit a low minimum noise figure F min of 0.62 (1.5) dB together with a high associated gain G A of 15.4 (13.3) dB. These F min values are among the lowest reported for deep submicrometer GaN HEMTs, and the G A are the best values so far in the literature, demonstrating the tremendous potential of AlInN/GaN HEMTs for microwave low‐noise applications.