β -Ga2O3 MESFETs with insulating Mg-doped buffer grown by plasma-assisted molecular beam epitaxy

In this work, we develop in situ Mg doping techniques in plasma-assisted molecular beam epitaxy (PAMBE) of β-Ga2O3 to compensate Si dopants at the substrate epilayer growth interface and eliminate parasitic leakage paths. Both abrupt and uniform Mg doping profiles over a wide range of concentrations were achieved in β-Ga2O3 epilayers grown by PAMBE. Capacitance–voltage characteristics of Si and Mg co-doped samples confirmed the compensating effect of the Mg dopants. Mg delta-doping was then integrated into a β-Ga2O3 metal-semiconductor field effect transistor structure and shown to be effective in eliminating source leakage. The results presented here show that Mg doping is a promising way to engineer insulating buffer layers for β-Ga2O3 lateral devices grown by PAMBE.