Effect of (AlGa)2O3 back barrier on device characteristics of β-Ga2O3 metal-oxide-semiconductor field-effect transistors with Si-implanted channel

An (AlGa)2O3 back barrier was employed for Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) with a Si-implanted n-Ga2O3 channel layer. The insertion of the back barrier led to strong confinement of electrons in the channel layer, and a shallower pinch-off characteristic with shifting a threshold gate voltage by +8 V was attained for the MOSFET with the back barrier compared to the conventional one without it. The excellent gate controllability represented by a subthreshold slope of 129 mV/decade was also achieved for the back-barrier MOSFET; whereas it was 337 mV/decade for the non-back-barrier one.