High conductivity of n-type β-Ga2O3(010) thin films achieved through Si doping by mist chemical vapor deposition

Abstract

Currently, β-Ga2O3 has attracted significant attention as a wide bandgap semiconductor, and numerous growth techniques are being explored to control its carrier concentration for various applications. In this study, we investigated the homoepitaxial growth of Si-doped β-Ga2O3 thin films on a Fe-doped β-Ga2O3 substrate using the mist chemical vapor deposition (CVD) technique developed in our group to obtain highly conductive thin films. Using mist CVD, we obtained highly crystalline Si-doped β-Ga2O3 thin films with a full-width at half-maximum of ∼40 arc sec for the (020) peak in the x-ray diffraction rocking curve. Atomic force microscopy studies indicated considerably smooth surfaces of the films with a small root mean square roughness (less than 0.5 nm). Furthermore, we controlled the carrier concentration in the range of 3.85 × 1018 to 2.58 × 1020 cm−3 by varying the Si concentration in the precursor solution. The film exhibits the highest conductivity of 2368 S/cm (mobility = 57.2 cm2/V s at the carrier concentration of 2.58 × 1020 cm−3). This study is expected to promote the application of β-Ga2O3 in devices.