MOCVD homoepitaxy of Si-doped (010) β-Ga_2O_3 thin films with superior transport properties

摘要

Record-high electron mobilities were achieved for silicon-doped (010) beta-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-10(16)cm(-3). Record carrier mobilities of 184cm(2)/Vs at room temperature and 4984cm(2)/Vs at low temperature (45K) were measured for beta-Ga2O3 thin films with room-temperature doping concentrations of 2.5x10(16) and 2.75x10(16)cm(-3), respectively. Analysis of temperature-dependent Hall mobility and carrier concentration data revealed a low compensation concentration of 9.4x10(14)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 120meV. The demonstration of high-purity and high-quality beta-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.