MOCVD homoepitaxy of Si-doped (010) β-Ga2O3 thin films with superior transport properties

Abstract

Record-high electron mobilities were achieved for silicon-doped (010) β-Ga2O3 homoepitaxial films grown via metalorganic chemical vapor deposition (MOCVD). Key growth parameters were investigated to reduce the background doping and compensation concentration. Controllable n-type Si doping was achieved as low as low-1016 cm-3. Record carrier mobilities of 184 cm2/V s at room temperature and 4984 cm2/V s at low temperature (45 K) were measured for β-Ga2O3 thin films with roomerature doping concentrations of 2.5 × 1016 and 2.75 × 1016 cm-3, respectively. Analysis of temperature-dependent Hall mobility and carrier concentration data revealed a low compensation concentration of 9.4 × 1014 cm-3. Using the two-donor model, Si on the tetrahedrally coordinated Ga(I) site represented the primary shallow donor state, and the secondary donor state was found to possess an activation energy of 120 meV. The demonstration of high-purity and high-quality β-Ga2O3 thin films with uniform and smooth surface morphology via MOCVD will harness its advantages as an ultrawide-bandgap semiconductor for power electronic and short-wavelength optoelectronic device applications.