High voltage semiconductor devices

摘要

A high-voltage semiconductor device such as a transistor (20) includes first and second trenches that define a mesa (22a) on a semiconductor substrate (21). First and second field plate members (24a,24b) are respectively disposed in the first and second trenches, with each of the first and second field plate members being separated from the mesa by a dielectric layer (28a). The mesa includes a plurality of sections, each section having a substantially constant doping concentration gradient, the gradient of one section being at least 10% greater than the gradient of another section.