Patent ID: 7943989

Claim:
A semiconductor power device comprising: a semiconductor substrate having a plurality of trenches opened from a top surface; wherein every two adjacent trenches are separated by a volume of said semiconductor substrate constituting a pillar having a pillar conductivity type; and all sidewalls of each of said trenches are covered by a plurality of epitaxial layers of alternating conductivity types disposed on two opposite sides and substantially symmetrical to a central gap-filler layer disposed between two innermost epitaxial layers of an innermost conductivity type as one of said alternating conductivity types wherein said central gap-filler layer of a central conductivity type opposite the innermost conductivity type having a width substantially the same as said plurality of epitaxial layers of alternating conductivity types and significantly smaller than said pillar, and wherein said epitaxial layers of said alternating conductivity types and said central gap-filler layer constituting nano tubes functioning as conducting channels extending along a sidewall direction of each of said trenches.