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

Abstract Highly oriented crystalline Ga 2 O 3 thin films were fabricated at room temperature (RT) by excimer laser annealing. Amorphous Ga 2 O 3 thin films were grown on α -Al 2 O 3 (0001) substrates at RT by the pulsed laser deposition method using a focused KrF excimer laser and a sintered β -Ga 2 O 3 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 β -Ga 2 O 3 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.