Heterointegrated Ga₂O₃-on-SiC RF MOSFETs With f_T/f_max of 47/51 GHz by Ion-Cutting Process

Heterointegrated Ga2O3-on-SiC radiofrequency (RF) MOSFETs with record-high frequency performances were reported. A two-dimensional electron gas like channel with a high electron concentration and decent mobility was formed through the shallow implantation of Si into the beta-Ga2O3 (-201) nanomembrane integrated on the highly thermal conductive 4H-SiC substrate through an ion-cutting process. The resultant MOSFET yields a high current density of 661 mA/mm and a transconductance (g(m)) of 57 mS/mm. A record-high current cut-off frequency (f(T)) of 47 GHz and maximum oscillation frequency (f(max)) of 51 GHz were achieved with the gate length (LG) scaled down to 0.1 mu m. Furthermore, the device with L-G = 0.1 mu m showcases an output power density of 296 mW/mm and a high power gain of 11 dB at 2 GHz in continue wave (CW) mode. It is attributed to the enhanced gate control, elevated current output, and improved thermal conductivity of the heterointegrated Ga2O3 on SiC by ion-cutting process.