Si-doped β-(Al0.26Ga0.74)2O3 thin films and heterostructures grown by metalorganic vapor-phase epitaxy

We report on n-type degenerate doping in beta-(Al0.26Ga0.74)(2)O-3 epitaxial thin films grown by metalorganic vapor-phase epitaxy and modulation doping in beta-(Al0.26Ga0.74)(2)O-3/beta-Ga2O3 heterostructures. Alloy composition is confirmed using high-resolution X-ray diffraction measurements. Carrier concentration in the thin films is proportional to the silane molar flow. Room-temperature Hall measurements showed a high carrier concentration of 6 x 10(18) cm(-3) to 7.3 x 10(19) cm(-3) with a corresponding electron mobility between 53-27 cm(2) V-1 s(-1) in uniformly doped beta-(Al0.26Ga0.74)(2)O-3 layers. Modulation doping is used to realize a total electron sheet charge of 2.3 x 10(12) cm(-2) in a beta-(Al0.26Ga0.74)(2)O-3/beta-Ga2O3 heterostructure using a uniformly doped beta-(Al0.26Ga0.74)(2)O-3 barrier layer and a thin spacer layer. (C) 2019 The Japan Society of Applied Physics