Effect of Post-Annealing and Oxygen on the Properties of Sn-Doped β-Ga2O3 Thin Film

초록

beta-Ga2O3 is a remarkable material for next-generation power semiconductors and optoelectronics owing to its suitable properties, including excellent thermal and chemical stability, wide band gap, and large breakdown voltage. In this study, Sn-doped beta-Ga2O3 thin films with the thickness of 200 nm were deposited on Si substrates at different O2 flow rates using reactive sputtering. After sputtering, the samples were post-annealed at various temperatures and time, and the structural and electrical properties of the Sn-doped beta-Ga2O3 thin films were investigated. X-ray diffraction analysis confirmed the appearance of the beta phase of Ga2O3 at 600 degrees C, and the crystallization trend of each condition was investigated. The surface morphology of the films was investigated using scanning electron microscopy, whereby cracks were observed above 600 degrees C, which is likely ascribed to the film stress owing to the lattice and thermal expansion coefficient mismatch between Si substrate and Ga2O3 film. Finally, the electrical properties of the Ga2O3 thin films were examined by Hall-effect measurement. Therefore, the effects of the post-annealing and O2 flow rate conditions on Sn-doped beta-Ga2O3 thin films were successfully investigated.

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