Patent ID: 8648413
Filing Date: 2014-02-11
Classification: H01L

Abstract:
1. A super-junction trench MOSFET comprising: a substrate of a first conductivity type; an epitaxial layer of the first conductivity type onto said substrate, wherein said epitaxial layer has a lower doping concentration than said substrate; a plurality of gate trenches starting from a top surface of said epitaxial layer and extending downward into said epitaxial layer, each of said gate trenches being padded by a first gate insulation layer along a lower inner surface and padded by a second gate insulation layer along an upper inner surface, wherein said first gate insulation layer has a greater thickness than said second gate insulation layer; a plurality of mesas between two adjacent gate trenches; a plurality of first doped column regions of a second conductivity type formed in said mesas; a plurality of second doped column regions of the first conductivity type formed in said mesas and adjacent to sidewalls of said gate trenches, located in parallel and surrounding with said first doped column regions; split gate electrodes along said upper inner surface of each of said gate trenches and close to said second gate insulation layer, said split gate electrodes having bottoms interfaced with said first gate insulation layer and having sidewalls interfaced with said second gate insulation layer; a source electrode disposed between said split gate electrodes and extending deeper than said split gate electrodes in each of said gate trenches, said source electrode having a lower portion which is underneath said split gate electrodes and interfaced with said first gate insulation layer, and having an upper portion which is adjacent to said split gate electrodes and interfaced with said second gate insulation layer; a plurality of body regions of the second conductivity type formed in said mesas and adjacent to said split gate electrodes, covering a top surface of said first doped column regions and said second doped column regions between two adjacent gate trenches; multiple trenched source-body contacts in each of said mesas in an active area, each filled with a contact metal plug and extending into said body regions; and a plurality of source regions of said first conductivity type at least formed along channel regions near top surface of said mesas in said active area.