Metalorganic vapor phase epitaxy of β-(AlxGa1−x)2O3 (x = 0–0.55) and multilayer structure on (100) β-(Al0.24Ga0.76)2O3 substrates

We successfully achieved the growth of β-(AlxGa1−x)2O3 (x = 0–0.55) on a (100) β-Al0.24Ga0.76O3 substrate using metalorganic vapor phase epitaxy (MOVPE). A stacked layer composed of β-(Al0.47Ga0.53)2O3/β-Ga2O3 on a β-Al0.24Ga0.76O3 substrate was demonstrated. High-resolution x-ray diffraction and reciprocal space mapping analysis verified the coherent epitaxial growth of phase-pure β-(AlxGa1−x)2O3 thin films up to an Al composition of x = 0.55. Films with higher Al content exhibited partial plastic strain relaxation. The multilayer structure of the β-(Al0.47Ga0.53)2O3/β-Ga2O3 thin film exhibited good quality and coherent growth. Atomic force microscopy measurements proved a surface roughness well below 0.42 nm for the fully strained films and about 1 nm for the relaxed ones. These results indicate that the MOVPE technique has significant potential for the fabrication of β-Ga2O3-based heterojunctions suitable for device applications.