β –Ga₂O₃ Sub-Micron FinFETs With Si Delta-Doped Channel Modulating >3 × 10 13 cm –2 Charge Density

This letter reports on the design and demonstration of high-performance β-Ga₂O₃ FinFETs utilizing MOCVD grown Si delta-doped channel to achieve enhanced carrier transport and electrostatic control. A high sheet charge density of 3.3×10¹³ cm⁻² was modulated using 100 nm fin channels, delivering a peak drain current of 137 mA/mm and a peak transconductance of 20 mS/mm. The FinFET architecture enables strong gate modulation achieving a high IOn/IOffratio between 108-10⁹. A low contact resistance of 0.42 Ω.mm was achieved to the Si delta doped channel using MOCVD contact regrowth. Small-signal RF characterization revealed a current gain cut-off frequency (fT`) of 3.8 GHz and maximum oscillation frequency (fMAX) of 2.1 GHz for 0.9 micrometer gate length. These results demonstrate the efficacy of combining precision delta-doping and 3D FinFET geometry for high-frequency β-Ga₂O₃ electronics, establishing a platform for future RF and high-power applications.