Microgrooves with low-index facets in halide vapor deposited (001) β-Ga2O3: origin of reverse leakage current in Schottky barrier diodes observed by high-sensitive emission microscopy and synchrotron X-ray topography

We have found microgrooves on the (001) β -Ga _2 O _3 epitaxial deposited by halide vapor-phase epitaxy in Schottky barrier diodes to be killer defects at the point of reverse leakage-current flow [−10.0 μ A at −64 V]. The microgrooves tended to align in the [010] direction and each microgroove consisted of (100), (001), and ( $\mathop{1}\limits^{\unicode{x00305}}$ 02) low-index microfacets. The microgrooves were accompanied by polycrystalline defects on the [ $\mathop{1}\limits^{\unicode{x00305}}$ 00] side. The electric field at the bottom of the microgrooves reached 5.27 × 10 ^5 V cm ^−1 at $-$ 50 V, which is approximately twice that of the flat surface.