Semiconductor Device Including Trenches and Method of Manufacturing a Semiconductor Device

A method of manufacturing a semiconductor device, comprising:

• forming a first transistor cell including a first gate electrode in a first trench;
• forming a second transistor cell including a second gate electrode in a second trench, wherein the first and second gate electrodes are electrically connected;
• forming a third trench between the first and second trenches, wherein the third trench extends deeper into a semiconductor body from a first side of the semiconductor body than the first and second trenches;
• and
• forming a dielectric in the third trench covering a bottom side and sidewalls of the third trench,
• wherein forming the first, second and third trenches includes forming a patterned mask at the first side, wherein the patterned mask includes a first type of opening having a greater lateral width than a second type of opening, and etching the first and second trenches through the second type of opening and the third trench through the first type of opening.

A method of manufacturing a semiconductor device, comprising:

• forming a first transistor cell including a first gate electrode in a first trench;
• forming a second transistor cell including a second gate electrode in a second trench, wherein the first and second gate electrodes are electrically connected;
• forming a third trench between the first and second trenches, wherein the third trench extends deeper into a semiconductor body from a first side of the semiconductor body than the first and second trenches;
• forming a dielectric in the third trench covering a bottom side and sidewalls of the third trench;
• and
• introducing dopants through a bottom side of the third trench into the semiconductor body before filling up the third trench.

A semiconductor device, comprising:

• a first transistor cell including a first gate electrode in a first trench;
• a second transistor cell including a second gate electrode in a second trench, wherein the first and second gate electrodes are electrically connected;
• a third trench between the first and second trenches, wherein the third trench extends deeper into a semiconductor body from a first side of the semiconductor body than the first and second trenches;
• and
• a dielectric in the third trench covering a bottom side and walls of the third trench,
• wherein the semiconductor body includes a drift zone of a first conductivity type adjoining a bottom side of a body region of a second conductivity type complementary to the first conductivity type,
• wherein a second semiconductor region of the second conductivity type including a net doping concentration higher than the drift zone adjoins a bottom side of the first and second trenches.