Patent ID: 9064897
Filing Date: 2015-06-23
Classification: H01L

Abstract:
1. A method for forming a semiconductor device having an active cell array and a termination region, the method comprising: forming an epitaxial layer of a first conductivity type disposed on a top surface of the semiconductor substrate of the first conductivity type, wherein the epitaxial layer includes a surface shielded region that is heavily doped positioned above a voltage blocking region that is lightly doped; forming an active cell array including a body region of a second conductivity type that is opposite of the first conductivity type, a source region of the first conductivity type and a gate disposed near the top surface of the surface shielded region and a drain disposed at a bottom surface of the semiconductor substrate, a plurality of trenches formed in the surface shielded region, wherein the trenches are lined with a trench insulation material and filled with an electrically conductive trench filling material configured to be in electrical contact with a source electrode on top of the surface shielded region and in electrical contact with the source region, and a plurality of buried doped regions of the second conductivity type, wherein each buried doped region is positioned below one of the plurality of trenches, and wherein the buried doped regions extend to a depth substantially the same as the bottom surface of the surface shielded region; forming a termination region surrounding the active cell array, the termination comprising two or more zones and an electrical disconnect configured to prevent an electrical short between the body layer and an edge of the semiconductor device; wherein, the termination region is formed in the epitaxial layer, wherein the termination region includes a plurality termination structures, each of the termination structures comprising, a trench shield electrode and a buried doped-region of the second conductivity type such that a cumulative depth of the trench and buried region is substantially the same as a depth of the surface shielded region; wherein each termination structure in a first zone closest to the active region includes an electrical connection between its trench shield electrode and a portion of the body layer closer to the active cell array; and wherein each termination structure in a second zone includes an electrical connection between its trench shield electrode and a portion of the body layer further away from the active cell array, and a spacing between each termination structure in the second zone increases with increasing distance away from the active cell array.