Patent ID: 8772868

Claim:
A power device comprising: a semiconductor substrate of a first conductivity type; an epitaxial layer of the first conductivity type disposed on the semiconductor substrate; a first trench disposed in the epitaxial layer of the first conductivity type; a second trench disposed in the epitaxial layer of the first conductivity type; and a mesa disposed between the first trench and the second trench, the mesa defining a pillar of the first conductivity type from the epitaxial layer of the first conductivity type; a body region of a second conductivity type disposed in the epitaxial layer of the first conductivity type; a source region of the first conductivity type disposed in the body region; a gate electrode disposed on the body region and disposed on at least a portion of the source region, the gate electrode being insulated from the body region and the source region; and a source metal layer in electrical contact with the source region, the first trench including a first pillar of the second conductivity type, the second trench including a second pillar of the second conductivity type, the second pillar of the second conductivity type including: a first trench epitaxial layer of the second conductivity type disposed on a trench sidewall of the second trench and a trench bottom surface of the second trench, a second trench epitaxial layer of the second conductivity type disposed on the first trench epitaxial layer of the second conductivity type, and an insulating material layer disposed on the second trench epitaxial layer of the second conductivity type, the first pillar of the second conductivity type and the second pillar of the second conductivity type forming pillars of alternating conductivity type with the pillar of the first conductivity type.