Semiconductor devices exhibiting minimum on-resistance

A semiconductor device comprising:

• a body of semiconductor material including first, second and third zones having alternating conductivity types, said first and third zones being of one type conductivity, said second zone being of an opposite type conductivity and forming first and second PN junctions with said first and third zones, respectively;
• said body of semiconductor material having first and second opposed major surfaces, said first major surface being comprised of a portion of said first zone and a portion of said second zone, said body having a substantially vertical trench extending into said body from said first major surface and through said first and second zones and into the third zone to define a pedestal portion of said body including portions of said first, second and third zones, said trench extending a length L.sub.t into said third zone, said third zone portion of said pedestal having a width W and an aspect ratio of L.sub.t /W which is greater than or equal to 0.5 throughout said pedestal;
• an insulation layer disposed in said trench on said portions of said first, second and third zones exposed by said trench;
• a gate electrode disposed in said trench adjacent said insulation layer and coextensive with said second zone and extending past said second junction and substantially covering said exposed portion of said third zone;
• a first main electrode disposed on said first major surface in ohmic contact with said first zone;
• and
• a second main electrode disposed on said second major surface in ohmic contact therewith;
• the main ON-state current path through said device extending between said first and second main electrodes.