Patent ID: 7291884
Filing Date: 2007-11-06
Classification: H01L

Abstract:
1. A trench MIS device comprising: a substrate of a first conductivity type; a first epitaxial layer of the first conductivity type on the substrate, the first epitaxial layer being doped more lightly than the substrate; a second epitaxial layer of a second conductivity type on the first epitaxial layer, a trench being formed in the second epitaxial layer, the trench having a bottom in the second epitaxial layer above an interface between the first and second epitaxial layers; a gate in the trench; a gate insulating layer along a sidewall of the trench, the gate being electrically insulated from the second epitaxial layer by the gate insulating layer; a bottom insulating layer on the bottom of the trench, the bottom insulating layer being thicker than the gate insulating layer; a drain-drift region of the first conductivity type extending between the bottom of the trench and the first epitaxial layer, the drain-drift region forming a PN junction with the second epitaxial layer, the PN junction extending between the trench and the first epitaxial layer, wherein the PN junction is aligned with an edge of the bottom insulating layer.