Variant of Excess Current in 4H-SiC pn Structures

Abstract

Excess currents and defects were investigated in the 4H-SiC p+nn+ structures created by implantation. It was found that the principal p+n junction is shunted by several or multiple Schottky barriers connected in parallel to the principal pn junction and formed by a contact of Al on the surface of p+-layer with n-layer perhaps with participation of carbon coated surfaces of the pits or other defects. Amount and area of Schottky barriers vary for different pn structures, in connection with which vary as the value of the excess current and character of the current-voltage dependence, and, apparently, that was observed in some cases, the instability of excess current.