Semiconductor device having a trench gate and method for manufacturing

A semiconductor device, comprising:

• a first semiconductor area and a second semiconductor area;
• a semiconductor body area between the first semiconductor area and the second semiconductor area, wherein a doping characteristic of the semiconductor body area is inverse to a doping characteristic of the first semiconductor area and the second semiconductor area;
• a trench which extends adjacent to the semiconductor body area from a semiconductor surface of the first semiconductor area at least to the second semiconductor area;
• and
• a gate arranged in the trench and separated from the semiconductor body area by an insulation layer, wherein the trench comprises a top trench portion which extends from the semiconductor surface at least to a depth which is greater than a depth of the first semiconductor area, wherein the trench further comprises a bottom trench portion which extends subsequently from the top trench portion into to the second semiconductor area, and wherein the top trench portion comprises a first maximum lateral dimension and the bottom trench portion comprises a region located in the second semiconductor area, the region having a second lateral dimension being greater than the first maximum lateral dimension, and
• wherein the gate comprises a cavity in the bottom area.