Semiconductor device having a superjunction-structure

A semiconductor device comprising a transistor, the transistor comprising:

• a plurality of gate trenches formed in a semiconductor substrate, the gate trenches patterning the semiconductor substrate into ridges extending in a first horizontal direction, the ridges being arranged between two adjacent gate trenches, respectively;
• a gate electrode arranged in at least one of the gate trenches;
• a source region of a first conductivity type electrically coupled to a source terminal;
• a channel region comprising a doped portion of a second conductivity type;
• a current spread region of the first conductivity type;
• and
• a drain region electrically coupled to a drain terminal,
• wherein the source region, the channel region and a part of the current spread region are arranged in the ridges,
• wherein the gate electrode is insulated from the channel region and the current spread region,
• wherein the source region is arranged at least in a central portion of the ridge,
• the semiconductor device further comprising a superjunction structure arranged at a larger distance to the source region than the channel region and comprising:
• a first compensation region of the first conductivity type electrically coupled to the drain terminal;
• and
• a second compensation region of the second conductivity type,
• wherein the first and the second compensation regions are adjacent to each other,
• wherein a doping concentration of the doped portion of the second conductivity type of the channel region decreases in a second horizontal direction intersecting the first horizontal direction from a region close to the gate electrode to the central portion of the ridge.