Semiconductor device

Abstract

A semiconductor device according to the present invention includes a semiconductor layer of SiC of a first conductivity type, a plurality of body regions of a second conductivity type formed in the surface portion of the semiconductor layer with each body region forming a unit cell, a source region of the first conductivity type formed in the inner portion of the body region, a gate electrode facing the body region across a gate insulating film, a drain region of the first conductivity type and a collector region of the second conductivity type formed in the rear surface portion of the semiconductor layer such that the drain region and the collector region adjoin each other, and a drift region between the body region and the drain region, wherein the collector region is formed such that the collector region covers a region including at least two unit cells in the x-axis direction along the surface of the semiconductor layer.

1 . A semiconductor device comprising:
 a semiconductor layer of SiC of a first conductivity type;   a plurality of body regions of a second conductivity type formed in the surface portion of the semiconductor layer with each body region forming a unit cell;   a source region of the first conductivity type formed in the inner portion of the body region;   a gate electrode facing the body region across a gate insulating film;   a drain region of the first conductivity type and a collector region of the second conductivity type formed in the rear surface portion of the semiconductor layer, the drain region and the collector region adjoining each other; and   a drift region between the body region and the drain region, wherein   the collector region is formed such that the collector region covers a region including at least two unit cells in the x-axis direction along the surface of the semiconductor layer.   
     
     
         2 . A semiconductor device comprising:
 a semiconductor layer of SiC of a first conductivity type;   a body region of a second conductivity type formed in the surface portion of the semiconductor layer;   a source region of the first conductivity type formed in the inner portion of the body region;   a gate electrode facing the body region across a gate insulating film;   a drain region of the first conductivity type and a collector region of the second conductivity type formed in the rear surface portion of the semiconductor layer, the drain region and the collector region adjoining each other; and   a drift region between the body region and the drain region, wherein   an x-axis width Wc of the collector region along the surface of the semiconductor layer is made at least two times greater than a y-axis thickness Td of the drift region along the thickness direction of the semiconductor layer.   
     
     
         3 . A semiconductor device according to  claim 1 ,
 wherein the drain region has an x-axis width greater than or equal to that of the collector region.   
     
     
         4 . A semiconductor device comprising:
 a semiconductor layer of SiC of a first conductivity type;   a body region of a second conductivity type formed in the surface portion of the semiconductor layer;   a source region of the first conductivity type formed in the inner portion of the body region;   a gate electrode facing the body region across a gate insulating film;   a drain region of the first conductivity type and a collector region of the second conductivity type formed in the rear surface portion of the semiconductor layer, the drain region and the collector region adjoining each other;   a drift region between the body region and the drain region; and   an insulating layer disposed between the drain region and the collector region, the insulating layer being formed deeper than the drain region and the collector region from the rear surface of the semiconductor layer in the y-axis direction along the thickness direction of the semiconductor layer.   
     
     
         5 . A semiconductor device according to  claim 4 , wherein the insulating layer includes an insulating film or a high-resistance layer. 
     
     
         6 . A semiconductor device according to  claim 4 ,
 wherein the insulating layer includes an insulating material having a dielectric constant lower than SiC.   
     
     
         7 . A semiconductor device according to  claim 6 , wherein the insulating layer includes SiO 2 . 
     
     
         8 . A semiconductor device comprising:
 a semiconductor layer of SiC of a first conductivity type;   a body region of a second conductivity type formed in the surface portion of the semiconductor layer;   a source region of the first conductivity type formed in the inner portion of the body region;   a gate electrode facing the body region across a gate insulating film;   a drain region of the first conductivity type and a collector region of the second conductivity type formed in the rear surface portion of the semiconductor layer, the drain region and the collector region adjoining each other; and   a drift region between the body region and the drain region; wherein   the upper end of the collector region is positioned closer to the surface of the semiconductor layer than the upper end of the drain region in the y-axis direction along the thickness direction of the semiconductor layer.   
     
     
         9 . A semiconductor device according to  claim 8 , wherein the rear surface of a semiconductor layer extends across the interface between the drain region and the collector region to make both surfaces flush with each other. 
     
     
         10 . A semiconductor device according to  claim 1 , further comprising:
 a field stop region formed to extend over the drain region and the collector region in the x-axis direction along the surface of the semiconductor layer, the field stop region being disposed between the drift region, and the drain region and the collector region.   
     
     
         11 . A semiconductor device according to  claim 1 , wherein
 the semiconductor device includes a planar-gate structure where the gate electrode is disposed on the semiconductor layer.   
     
     
         12 . A semiconductor device according to  claim 1 , wherein
 the semiconductor device includes a trench-gate structure where the gate electrode is embedded in a trench formed in the semiconductor layer.