基于SiC的C波段β-Ga₂O₃射频功率MOSFET实现高输出功率密度与低微波噪声系数

In this letter, we show that -Ga2O3-on-SiC RF power metal-oxide-semiconductor field-effect transistors (MOSFETs) can achieve a high output power density ( P_ out ) for C-band applications by implementing a heavily doped channel to reduce channel resistance and a high thermal conductivity SiC substrate to enhance heat dissipation. By doing so, -Ga2O3-on-SiC RF MOSFETs demonstrate a drain current density ( I_ D ) of 730 mA/mm and peak transconductance (gm) of 81 mS/mm. As a result, cut-off frequency ( f_ T ) and maximum oscillation frequency ( f_ ) of 19.2 and 35.3 GHz are achieved, respectively. Benefited from the suppressed self-heating effect under high drain bias ( V_ DS ) operation condition, the RF power performances with output power density ( P_ out ) =3.5 W/mm at 4 GHz and P_ out =3.2 W/mm at 6 GHz are reported. To the best of all the authors’ knowledge, this is the highest P_ out at C-Band among all -Ga2O3 RF power FETs. In addition, this work studies the microwave noise characteristics of the -Ga2O3 RF MOSFETs at frequency (f) range of 2–15 GHz. The device is able to achieve a low minimum-noise figure (NFmin) of 1.4 dB at 2 GHz and 1.8–2.5 dB at 4–6 GHz. -Ga2O3 RF power MOSFETs with heavily doped channel and high thermal conductivity substrate verify their great promise for future high power, high frequency, and low noise RF electronics.