Close oxygen coupled low-pressure chemical vapor deposition growth of high quality β-Ga2O3 on sapphire

Abstract

We report on the close oxygen coupled low-pressure chemical vapor deposition (COC-LPCVD) hetero-epitaxial growth of atomically smooth (− 201) oriented β− Ga2O3 on c-plane sapphire. Utilizing a dedicated line within the main tube, O2 could be delivered to the substrate surface which enables effective control of growth regime. Under optimized conditions (Ga-rich and near stoichiometric feed rate), step flow growth was obtained with X-ray rocking curve full-width at half maximum of 0.09◦ and 0.20◦ at a growth rate of 0.49 μm/h and 3.42 μm/h, respectively. On the other hand, oxygen-rich growth at high growth rates produced in-plane rotational domains. In addition, the alignment of single crystal (− 201) β − Ga2O3 with respect to the sapphire offcut direction was revealed such that [-20-1] β− Ga2O3 is along [11–20] (offcut direction) sapphire. This study demonstrates the potential of the versatile COC-LPCVD system on the thin film growth of high quality β − Ga2O3.