Patent ID: 9324823
Filing Date: 2016-04-26
CPC Classification: H01L

Claim Text:
1. A semiconductor device, comprising: a semiconductor body having a first surface; a first trench formed in the semiconductor body, the first trench comprising first and second sidewalls extending from the first surface in a vertical direction and a first trench bottom extending between the first and second sidewalls in a first lateral direction; a field dielectric filling the first trench; and a second trench formed within the first trench in the field dielectric comprising inner and outer sidewalls, wherein first and second sidewalls of the first trench and the inner and outer sidewalls of the second trench extend along the semiconductor body in a second lateral direction that is perpendicular to the first lateral direction and perpendicular to the vertical direction, and wherein the second trench comprises a widened portion adjacent to a narrow portion in the second lateral direction, wherein, in the widened portion, the inner and outer sidewalls extend the parallel to the first sidewall in the second lateral direction, and wherein, in the narrow portion, one of the inner and outer sidewalls is non-perpendicular and non-parallel to the first sidewall in the second lateral direction.