Heterointegrated Ga2O3-on-SiC RF MOSFETs With f T/f max of 47/51 GHz by Ion-Cutting Process

Heterointegrated Ga2O3-on-SiC radio-frequency (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 ( ${g}_{\text {m}}{)}$ of 57 mS/mm. A record-high current cut-off frequency ( ${f}_{\text {T}}{)}$ of 47 GHz and maximum oscillation frequency ( ${f}_{\text {max}}{)}$ of 51 GHz were achieved with the gate length ( ${L}_{\text {G}}{)}$ scaled down to $0.1~\mu \text{m}$ . Furthermore, the device with ${L}_{\text {G}}= 0.1\,\,\mu \text{m}$ 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.