Patent ID: 8058685

Claim:
A trench semiconductor power MOSFET comprising a plurality of transistor cells with each cell composed of a plurality of first trenched gates surrounded by source regions heavily doped with a first conductivity type in an active area encompassed in a body regions of a second conductivity type above a drain region disposed on a bottom surface of a low-resistivity substrate of said first conductivity type, wherein: said plurality of transistor cells formed in an epitaxial layer with said first conductivity type over said low-resistivity substrate, and with a lower doping concentration than said low-resistivity substrate; said source region has doping concentration along channel region lower than along trenched source-body contact region at same distance from the surface of said epitaxial layer, and source junction depth is shallower along said channel region than along said trenched source-body contact, and the doping profile of said source region along the surface of said epitaxial layer has Gaussian-distribution from said trenched source-body contact to said channel region; said plurality of first trenched gates filled with doped poly padded with a first insulation layer as gate oxide; and each said transistor cell further comprising: at least a second trenched gate having wider trench width than said first trenched gates and filled with doped poly padded with a first insulation layer as gate oxide; a second insulation layer functioning as contact interlayer; a plurality of trenched source-body contacts penetrating through said second insulation layer and said source regions, and extending into said body regions to contact both said source region and said body regions; at least a trenched gate contact penetrating through said second insulation layer and extending into said doped poly in said second trenched gate; a body contact area heavily doped with said second conductivity type around the bottom of each said trenched source-body contact; said MOSFET has multiple trenched floating gates in a termination area composed of a plurality of third trenched gates filled with said doped poly padded with said gate oxide surrounded by said body regions wherein there is no said source between two adjacent said third trenched gates in said termination area; trench depth of said multiple trenched floating gates is equal to or deeper than junction depth of said body regions, a source metal connected to said source regions and said body regions; and a gate metal connected to said second trenched gate.