Patent ID: 7936014

Claim:
A vertical semiconductor power MOSFET device comprising a plurality of semiconductor power cells with each cell comprising a trenched gate surrounded by a source region with first type conductivity in active area encompassed in a body region with second type conductivity above a drain region disposed on a bottom surface of a low-resistivity substrate with first type conductivity, wherein said trench MOSFET cell further comprising: an epitaxial layer of said first conductivity type over said substrate, said epitaxial layer having a lower doping concentration than the substrate; a first insulating layer serving as gate oxide lining the inner surface of openings for trench gates; a second insulating layer functioning as thick oxide interlayer; a plurality of trench contacts filled with a barrier layer and tungsten plugs; a source metal layer connected to the source regions and the body regions via trench source-body contacts; a gate-source clamp diode connected between a first gate metal and a source metal, composed of multiple back-to-back Zener diodes disposed inside of edge termination area; a gate-drain clamp diode connected between a second gate metal and a first drain metal, composed of multiple back-to-back polysilicon Zener diodes disposed outside of edge termination area without having said polysilicon Zener diode or said gate metal cross over said edge termination; said first drain metal connected to the epitaxial layer via trench drain contacts; a second drain metal layer formed on a bottom surface of the substrate; and said first and second gate metals connected together at gate lead frame through bonding wires.