Patent ID: 7732876

Claim:
A trench power transistor comprising: a first semiconductor region of a first conductivity type extending over and in contact with a second semiconductor region of the first conductivity type, the first semiconductor region having a lower dopant concentration than the second semiconductor region; a plurality of gate trenches extending into the first semiconductor region, each gate trench including a gate electrode and a gate dielectric layer lining sidewalls of each gate trench; well regions of a second conductivity type over and in contact with the first semiconductor region, each well region extending between and abutting every two adjacent gate trenches; a sinker trench extending through the first semiconductor region and terminating within the second semiconductor region, the sinker trench being laterally spaced from an outer one of the plurality of gate trenches, with no well regions abutting sidewalls of the sinker trench; source regions of the first conductivity type over and in contact with the well regions, the source regions flanking the gate trenches; and a conductive material in the sinker trench making electrical contact with the second semiconductor region along the bottom of the sinker trench and making electrical contact with a drain interconnect layer extending along the top of the sinker trench.