Electrical properties of heavily Sn-doped (AlGa)2O3 layers on β-Ga2O3 (010) substrates

Abstract

Abstract We report on the critical layer thickness for (AlGa)2O3 hetero-epitaxial growth on β-Ga2O3 (010) substrates via plasma-assisted molecular-beam epitaxy and on the electrical properties of heavily tin-doped (AlGa)2O3 layers. The aluminum composition in the (AlGa)2O3 layers was reproducibly controlled within 19% by changing aluminum fluxes. We achieved the pseudomorphic growth of the 1050 nm thick (Al0.12Ga0.88)2O3 and 420 nm thick (Al0.15Ga0.85)2O3 layers on β-Ga2O3 (010) substrates. The electron concentration, contact resistivity, and sheet resistance of the (Al0.10Ga0.90)2O3 layer with a tin concentration of 4 × 1019 cm−3 were 1 × 1018 cm−3, 3 × 10−5 Ω cm2, and 9 × 102 Ω/⎕, respectively.