Origin of reverse leakage current path in edge-defined film-fed growth (001) β-Ga_2O_3 Schottky barrier diodes observed by high-sensitive emission microscopy

摘要

We utilized ultra-high sensitive emission microscopy to investigate the origin of reverse leakage current of edge-defined film-fed grown (001) β-Ga_2O_3 Schottky barrier diodes. In the emission patterns, we observed a partially appearing void, having a typical width and depth of 300 and 83 nm, respectively, with a base angle of 75°, below the Schottky barrier contact on the β-Ga_2O_3 surface. Simulations show that the electric field at the bottom of the void reached 9 × 10~6 V/cm at a reverse bias of -60 V and in the case of an ideally flat surface 3.1 × 10~6 V/cm. This indicates that the reverse leakage current originates from an electric field concentration in the partially appearing voids on the surface. On the other hand, we have confirmed that there is no clear relationship between the leakage current path and the dislocations observed by synchrotron x-ray topography.