Oxygen-radical-assisted pulsed-laser deposition of β-Ga2O3 and β-(AlxGa1−x)2O3 films

Publication date: 15 August 2015
Source:Journal of Crystal Growth, Volume 424
Author(s): Ryo Wakabayashi , Takayoshi Oshima , Mai Hattori , Kohei Sasaki , Takekazu Masui , Akito Kuramata , Shigenobu Yamakoshi , Kohei Yoshimatsu , Akira Ohtomo
We report on impacts of oxygen-radical (O^⁎) atmosphere for pulsed-laser deposition (PLD) of β-Ga2O3 and β-(Al x Ga1−x )2O3 films on (010) β-Ga2O3 substrate in comparison with conventional PLD in O2 atmosphere. Severe sublimation of Ga species arising from insufficient oxidation in the O2 atmosphere resulted in substantial decrease in growth rate of the homoepitaxial films and condensation of Al content in the (Al x Ga1−x )2O3 films. In the case of O^⁎-assisted PLD, it was found that the growth rate of homoepitaxial films greatly recovered, and the Al content remained nearly identical to that in the target. Moreover, the use of O^⁎ allowed to reduce surface roughness of homoepitaxial films. These results indicate that O^⁎-assisted PLD is a powerful tool for fabricating β-Ga2O3-based heterostructures.