Deep Gate Trench IGBT

An insulated-gate bipolar transistor (IGBT) in a semiconductor substrate, said IGBT comprising:

• a collector at a bottom surface of said semiconductor substrate, a drift region having a first conductivity type situated over said collector, and a base layer having a second conductivity type opposite said first conductivity type situated over said drift region;
• a plurality of deep insulated trenches extending from a semiconductor surface above said base layer, into said drift region;
• each of said deep insulated trenches having a buried depletion electrode and at least one gate electrode disposed therein, said buried depletion electrode reaching deeper into said deep insulated trench than said at least one gate electrode;
• an active cell including an emitter adjacent said at least one gate electrode, and an implant zone, situated between adjacent deep insulated trenches;
• said implant zone being formed below said base layer and having said first conductivity type;
• a dummy cell neighboring said active cell, said dummy cell not having an emitter formed therein, wherein said implant zone does not extend to said dummy cell.