Growth and characteristics of β-Ga2O3 thin films on sapphire (0001) by low pressure chemical vapour deposition

Monoclinic beta phase Ga2O3 has been considered as a promising candidate for next generation radio frequency and high-power devices because of its ultrawide bandgap and high breakdown field. The development of epitaxial growth techniques and the synthesis of high quality beta-Ga2O3 thin films are crucial for the device applications. In this work, the heteroepitaxial beta-Ga2O3 thin films were grown on sapphire (0001) substrates by low pressure chemical vapor deposition. The influence of growth parameters such as the source/substrate temperatures, the oxygen/Ar gas flow rates, and the surface morphology of substrate on the resultant crystallinity and surface roughness of the beta-Ga2O3 films were investigated. The beta-Ga2O3 heteroepitaxial layer on sapphire exhibits an RMS roughness of 1.82 nm, an XRD rocking curve of 1.18 degrees, and a growth rate of 0.72 mu m/h. The beta-Ga2O3 film grown on the buffer layer exhibit a smoother surface, whereas the chemical etching and annealing lead to an improved crystallinity and a rough surface. However, there is a trade-off between the crystallization and the surface roughness.

Automated summary

The study investigates the influence of different growth parameters and substrate surface morphology on the crystallinity and surface roughness of beta-Ga2O3 thin films. It is found that beta-Ga2O3 film grown on sapphire substrate exhibits a smoother surface, but there is a trade-off between crystallization and surface roughness.