摘要
This article reports the fabrication and characterization of metal–semiconductor high electron mobility transistors (MS-HEMT) and metal–oxidesemiconductor (MIS-HEMT) grown on the semi-insulating SiC substrates with 0° and 4°-off axis. For the MIS-HEMT, the HfO 2 film was used as the insulator deposited by atomic layer deposition. With a gate length of 2 μm, MS-HEMT and MIS-HEMT devices with 4°-off SiC substrates exhibit a drain saturation current density (J DS,max ) of 895 and 1016 mA/mm, the maximum transconductance (G m,max ) of 225 and 175 mS/mm, a cut-off frequency (f T ) of 8.1 and 9.4 GHz, and a maximum oscillation frequency (f max ) of 22 and 27.4 GHz, respectively, which are better than those with 0° SiC substrates. Furthermore, the devices with 4°-off substrate are verified with less interface states and buffer traps through the temperature-dependent and pulse current–voltage measurements.