TRENCH FIELD EFFECT TRANSISTOR AND METHOD OF MAKING IT

摘要

A trench FET includes drain region (20), source region (18) and body region (22) extending between the source region (18) and the drain region (20). Insulated gate trenches (10) control conduction. Deep pillars (32) of opposite conductivity type to the drain face one another below the bottom of the trench. The pillars (32) extend in the example about 0.6 micron below the bottom of the trench into the drain region (20). The pillars are provided to create depletion regions at the p-n junction between the pillars (32) and drain (20). When a source-drain voltage is applied the depletion regions from the pillars (32) on either side of the trench extend towards one another to shield the trench region from the drain (20).