Low Pressure Chemical Vapor Deposition Growth of Wide Bandgap Semiconductor In2O3 Films

Wide-bandgap semiconductor indium sesquioxide (In2O3) thin films were grown on yttria-stabilized-zirconia (YSZ) substrates with (100), (110), and (111) orientations using a previously unexplored growth method: low pressure chemical vapor deposition. High purity metallic indium (In) and oxygen (O-2) were used as precursors, and argon (Ar) was used as the carrier gas. The growth condition was optimized to balance the precursor vapor pressure and the suppression of the gas phase reaction to facilitate the growth of high crystalline quality In2O3 films. The crystal structures of the asgrown films were determined to be body centered cubic bixbyite. By tuning the O-2 flow rate, In2O3 epitaxial growth rates of 21 mu m/h, 11 mu m/h, and 9.2 mu m/h were obtained for films grown on YSZ (100), (110), and (111) substrates, respectively. Representative surface roughness values determined by atomic force microscopy ranges between 0.73 and 10.5 nm. Room temperature electron Hall mobility of 139 cm(2)/V.s, 77 cm(2)/V.s, and 97 cm(2)/V.s for (100), (110), and (111) oriented In2O3 films respectively were obtained with electron concentrations of (similar to 1.0-1.3) X 10 18 cm(-3). Secondary ion mass spectroscopy suggests H as a possible contributor to the observed free carrier concentrations in the as-grown films. A room temperature photoluminescence peak was observed at similar to 1.16 eV, which is related to the transition involving deep-level defects. Optical bandgap was determined to be , similar to 3.35-3.41 eV via photoluminescence excitation spectroscopy.