Semiconductor Device with Field Dielectric in an Edge Area

Abstract

A semiconductor device includes a semiconductor body with transistor cells arranged in an active area and absent in an edge area between the active area and a side surface. A field dielectric adjoins a first surface of the semiconductor body and separates, in the edge area, a conductive structure connected to gate electrodes of the transistor cells from the semiconductor body. The field dielectric includes a transition from a first vertical extension to a second, greater vertical extension. The transition is in the vertical projection of a non-depletable extension zone in the semiconductor body, wherein the non-depletable extension zone has a conductivity type of body/anode zones of the transistor cells and is electrically connected to at least one of the body/anode zones.

What is claimed is: 
     
         1 . A semiconductor device, comprising:
 a semiconductor body comprising transistor cells arranged in an active area and absent in an edge area between the active area and a side surface of the semiconductor body;   a field dielectric adjoining a first surface of the semiconductor body and separating, in the edge area, a conductive structure connected to gate electrodes of the transistor cells from the semiconductor body, the field dielectric comprising a transition from a first to a second, greater vertical extension; and   a non-depletable extension zone of a conductivity type of body/anode zones of the transistor cells and electrically connected to at least one of the body/anode zones, wherein the transition is in the vertical projection of the non-depletable extension zone,   wherein the non-depletable extension zone surrounds the active area at uniform width.   
     
     
         2 . The semiconductor device of  claim 1 , wherein the non-depletable extension zone is electrically connected to a metallic load electrode. 
     
     
         3 . The semiconductor device of  claim 1 , wherein the non-depletable extension zone has an effective dopant dose greater than 2.5E12 cm −2 . 
     
     
         4 . The semiconductor device of  claim 1 , further comprising:
 a depletable extension zone of the conductivity type of the body/anode zones, directly adjoining the non-depletable extension zone, and arranged between the non-depletable extension zone and the side surface.   
     
     
         5 . The semiconductor device of  claim 4 , wherein the depletable extension zone has an effective dopant dose of at most 2.0E12 cm −2 . 
     
     
         6 . The semiconductor device of  claim 4 , further comprising:
 a spacer zone between the first surface and the depletable extension zone and forming a pn junction with the depletable extension zone.   
     
     
         7 . The semiconductor device of  claim 1 , wherein the conductive structure is a section of an electric connection between a gate construction and gate electrodes of the transistor cells. 
     
     
         8 . The semiconductor device of  claim 1 , wherein the non-depletable extension zone directly adjoins a body/anode zone of at least one of the transistor cells. 
     
     
         9 . The semiconductor device of  claim 1 , wherein a vertical extension of the non-depletable extension zone perpendicular to the first surface exceeds a vertical extension of the body/anode zones of the transistor cells. 
     
     
         10 . The semiconductor device of  claim 1 , further comprising:
 first zones of a first conductivity type opposite to a second conductivity type given by the conductivity type of the body/anode zones; and   second zones of the second conductivity type, the first and the second zones alternately arranged in the semiconductor body in the active area,   wherein in the active area, the second zones directly adjoin the body/anode zones and the first zones form pn junctions with the body/anode zones.   
     
     
         11 . The semiconductor device of  claim 1 , wherein an impurity concentration in the non-depletable extension zone does not decrease by more than 50% between a starting point of the transition, where a vertical extension of the transition starts to increase from the first vertical extension, and a reference point at a distance of at least 3 μm to the starting point. 
     
     
         12 . The semiconductor device of  claim 1 , further comprising:
 a metal gate pad in a vertical projection of a gate area of the edge area,   wherein the gate area is in a corner or along one lateral side of the semiconductor body,   wherein a portion of the non-depletable extension zone is formed along a line separating the active area and the gate area.   
     
     
         13 . The semiconductor device of  claim 1 , wherein along a circumferential line around the active area a net dopant concentration of the non-depletable extension zone is constant. 
     
     
         14 . The semiconductor device of  claim 1 , further comprising:
 first zones of a first conductivity type opposite to a second conductivity type given by the conductivity type of the body/anode zones; and   second zones of the second conductivity type, the first and the second zones alternately arranged in the semiconductor body in the active area and the edge area,   wherein in the active area, the second zones directly adjoin to the body/anode zones and the first zones form pn junctions with the body/anode zones.   
     
     
         15 . The semiconductor device of  claim 14 , wherein the non-depletable extension zone overlaps with the second zones, and wherein along a circumferential line around the active area, a net dopant dose of the non-depletable extension zone is constant. 
     
     
         16 . The semiconductor device of  claim 14 , further comprising:
 a depletable extension zone of the conductivity type of the body/anode zones,   wherein the depletable extension zone directly adjoins the non-depletable extension zone and at least one of the second zones in the edge area.   
     
     
         17 . The semiconductor device of  claim 16 , further comprising:
 a spacer zone between the first surface and the depletable extension zone and forming a pn junction with the depletable extension zone.   
     
     
         18 . The semiconductor device of  claim 1 , wherein the non-depletable extension zone has an effective dopant dose greater than 2E13 cm −2 . 
     
     
         19 . The semiconductor device of  claim 1 , wherein the non-depletable extension comprises straight first sections with a constant first net dopant concentration and laterally curved second sections, wherein the first sections connect the second sections and a second net dopant concentration of the second sections is at least twice as high as the first net dopant concentration. 
     
     
         20 . A half-bridge circuit, comprising:
 a semiconductor body comprising transistor cells arranged in an active area and absent in an edge area between the active area and a side surface of the semiconductor body;   a field dielectric adjoining a first surface of the semiconductor body and separating, in the edge area, a conductive structure connected to gate electrodes of the transistor cells from the semiconductor body, the field dielectric comprising a transition from a first to a second, greater vertical extension; and   a non-depletable extension zone of a conductivity type of body/anode zones of the transistor cells and electrically connected to at least one of the body/anode zones,   wherein the transition is in the vertical projection of the non-depletable extension zone,   wherein the non-depletable extension zone surrounds the active area at uniform width.