Ga2O3 films for electronic and optoelectronic applications

Abstract

Properties of Ga2O3 thin films deposited by electron-beam evaporation from a high-purity single-crystal Gd 3Ga5O12 source are reported. As-deposited Ga2O3 films are amorphous, stoichiometric, and homogeneous. Excellent uniformity in thickness and refractive index was obtained over a 2 in. wafer. The films maintain their integrity during annealing up to 800 and 1200°C on GaAs and Si substrates, respectively. Optical properties including refractive index (n=1.84-1.88 at 980 nm wavelength) and band gap (4.4 eV) are close or identical, respectively, to Ga2O3 bulk properties. Reflectivities as low as 10-5 for Ga2O 3/GaAs structures and a small absorption coefficient (≊100 cm-1 at 980 nm) were measured. Dielectric properties include a static dielectric constant between 9.9 and 10.2, which is identical to bulk Ga 2O3, and electric breakdown fields up to 3.6 MV/cm. The Ga2O3/GaAs interface demonstrated a significantly higher photoluminescence intensity and thus a lower surface recombination velocity as compared to Al2O3/GaAs structures. © 1995 American Institute of Physics.