A power semiconductor device includes an active device region disposed in a semiconductor substrate, an edge termination region disposed in the semiconductor substrate between the active device region and a lateral edge of the semiconductor substrate and a trench disposed in the edge termination region which extends from a first surface of the semiconductor substrate toward a second opposing surface of the semiconductor substrate. The trench has an inner sidewall, an outer sidewall and a bottom. The inner sidewall is spaced further from the lateral edge of the semiconductor substrate than the outer sidewall, and an upper portion of the outer sidewall is doped opposite as the inner sidewall and bottom of the trench to increase the blocking voltage capacity. Other structures can be provided which yield a high blocking voltage capacity such as a second trench or a region of chalcogen dopant atoms disposed in the edge termination region.