Observation of inhomogeneity of Schottky barrier height on 4H-SiC using the electrochemical deposition

We observed regions with a low Schottky barrier height on 4H-SiC surfaces by the electrochemical deposition of ZnO. In the initial stage of the deposition, ZnO grew preferentially in the regions with a low Schottky barrier height, and we were able to observe the ZnO film only in these regions if we stopped the deposition at a proper time. We compared the positions of the deposited film and the positions of etch pits revealed by molten salt etching. As a result, in an epitaxial 4H-SiC layer, although approximately half of the deposited films seemed to grow at the etch-pit defect positions, other deposited films were grown at positions without etch-pit defects. Therefore, the Schottky barrier heights were reduced by not only defects emerging as etch pits but also other kinds of origins in epitaxial 4H-SiC.