Demonstration of beta-(AlxGa1-x)(2)O-3/beta-Ga2O3 modulation doped field-effect transistors with Ge as dopant grown via plasma-assisted molecular beam epitaxy

摘要

beta-(AlxGa1-x)(2)O-3/beta-Ga2O3 heterostructures were grown via plasma-assisted molecular beam epitaxy. The beta-(AlxGa1-x)(2)O-3/beta-Ga2O3 barrier was partially doped by Ge to achieve a two-dimensional electron gas (2DEG) in Ga2O3. The formation of the 2DEG was confirmed by capacitance-voltage measurements. The impact of Ga-polishing on both the surface morphology and the reduction of the unintentionally incorporated Si at the growth interface was investigated using atomic force microscopy and secondary-ion mass spectrometry. Modulation doped field-effect transistors were fabricated. A maximum current density of 20mA/mm with a pinch-off voltage of % -6V was achieved on a sample with a 2DEG sheet charge density of 1.2 x 10(13)cm(-2). (C) 2017 The Japan Society of Applied Physics