β-Ga2O3 FinFETs with ultra-low hysteresis by plasma-free metal-assisted chemical etching

In this work, β-Ga2O3 fin field-effect transistors (FinFETs) with metalorganic chemical vapor deposition grown epitaxial Si-doped channel layer on (010) semi-insulating β-Ga2O3 substrates are demonstrated. β-Ga2O3 fin channels with smooth sidewalls are produced by the plasma-free metal-assisted chemical etching (MacEtch) method. A specific on-resistance (Ron,sp) of 6.5 mΩ·cm2 and a 370 V breakdown voltage are achieved. In addition, these MacEtch-formed FinFETs demonstrate DC transfer characteristics with near zero (9.7 mV) hysteresis. The effect of channel orientation on threshold voltage, subthreshold swing, hysteresis, and breakdown voltages is also characterized. The FinFET with channel perpendicular to the [102] direction is found to exhibit the lowest subthreshold swing and hysteresis.