The spicular trenches 130 in the active area 104 have a lower end pointing to the second side 102 of the semiconductor substrate 100. The lower end of the spicular trenches 130 define a level within the semiconductor substrate 100 which is substantially parallel to the first side 101 and the second side 102. The drift region 153 can be considered to include an upper drift region 153a and a lower drift region 153b. The upper drift region 153a extends from the level defined by the lower ends of the trenches 130 in the active area 104 toward the first side 101. The lower drift region 153b extends from the level defined by the lower ends of the spicular trenches 130 in the active area 104 toward the second side 102. The upper drift region 153a may also referred to as cell mesa region 120 when arranged between adjacent spicular trenches 130.

According to an embodiment, the upper drift region 153a and the lower drift region 153b may have the same doping concentration. According to an embodiment, the upper drift region 153a and the lower drift region 153b may have different doping concentrations.