Room-temperature fabrication of highly oriented β-Ga2O3 thin films by excimer laser annealing

Highly oriented crystalline Ga2O3 thin films were fabricated at room temperature (RT) by excimer laser annealing. Amorphous Ga2O3 thin films were grown on alpha-Al2O3 (0001) substrates at RT by the pulsed laser deposition method using a focused KrF excimer laser and a sintered beta-Ga2O3 target. Amorphous precursor films were irradiated by a non-focused KrF excimer laser (100-250 mJ/cm(2)) at RT. The results of x-ray and reflection high-energy electron diffraction measurements indicated that highly (101)-oriented crystalline beta-Ga2O3 thin films were obtained after RT laser annealing. The optical bandgaps of the crystalline thin films were approximately 4.7-4.9 eV, as determined from the UV/Vis transmittance. The film surfaces after laser annealing revealed slight planar grain growth, indicating a high degree of crystallinity and showed the root mean square roughnesses of 0.28-0.48 nm. (C) 2015 Elsevier B.V. All rights reserved.