Patent ID: 7579649

Claim:
A trench field effect transistor (trench-FET) comprising: a semiconductor body having opposed first and second major surfaces; a source metallisation at the first major surface; source contact regions of semiconductor doped to have a first conductivity type at the first major surface in contact with the source metallisation; body contact regions of semiconductor doped to have a second conductivity type opposite to the first conductivity type at the first major surface in contact with the source metallisation; a drain region of first conductivity type under the first major surface; a drain contact connected to the drain region; and insulated gates including a conductive gate in an insulated trench for controlling current flow between the source contact region and the drain region through mesa regions between the insulated gates, wherein the source contact regions and body contact regions alternate laterally across the first major surface, with the source contact region arranged in the insulated trench above the insulated gate; wherein the mesa regions comprise doped body regions of semiconductor doped to have the second conductivity type extending under the body contact regions to the drain region, the doped body regions having a lower doping density than the body contact regions.