Semiconductor device having body contact regions and corresponding methods of manufacture

Abstract

A semiconductor device includes a contact opening extending through a source region and a body region of the device. An electrically insulative spacer lines sidewalls of the semiconductor substrate formed by the contact opening, and is recessed along the sidewalls such that at least part of the source region or body region is uncovered by the electrically insulative spacer. A body contact plug is in the contact opening. A first body contact region formed adjacent a bottom of the contact opening adjoins the body contact plug at the bottom of the contact opening. A second body contact region formed in the part of the source region or body region uncovered by the electrically insulative spacer adjoins the body contact plug along the part of the source region or body region uncovered by the electrically insulative spacer.

What is claimed is: 
     
         1 . A semiconductor device, comprising:
 a semiconductor substrate having a first main surface;   a trench extending from the first main surface into the semiconductor substrate;   a gate electrode in the trench and insulated from the semiconductor substrate;   a source region having a first conductivity type and formed in the semiconductor substrate at the first surface and adjacent the trench;   a body region having a second conductivity type and formed in the semiconductor substrate below the first region and adjacent the trench;   a drift region having the first conductivity type and formed in the semiconductor substrate below the second region and adjacent the trench;   a contact opening extending through the source region and into the body region;   an electrically insulative spacer on sidewalls of the semiconductor substrate formed by the contact opening, wherein the electrically insulative spacer is recessed below the first main surface along the sidewalls such that at least part of the source region or body region is uncovered by the electrically insulative spacer;   a body contact plug in the contact opening;   a first body contact region having the second conductivity type and formed in the semiconductor substrate adjacent a bottom of the contact opening, wherein the first body contact region adjoins the body contact plug at the bottom of the contact opening; and   a second body contact region having the second conductivity type and formed in the part of the source region or body region uncovered by the electrically insulative spacer, wherein the second body contact region adjoins the body contact plug along the part of the source region or body region uncovered by the electrically insulative spacer.   
     
     
         2 . The semiconductor device of  claim 1 , wherein the source region extends to the sidewalls, wherein at least part of the source region is uncovered by the electrically insulative spacer, and wherein the second body contact region adjoins the body contact plug along the part of the source region uncovered by the electrically insulative spacer. 
     
     
         3 . The semiconductor device of  claim 1 , wherein the source region is separated from the sidewalls by the body region, wherein at least part of the body region is uncovered by the electrically insulative spacer, and wherein the second body contact region adjoins the body contact plug along the part of the body region uncovered by the electrically insulative spacer. 
     
     
         4 . The semiconductor device of  claim 1 , wherein the contact opening terminates within the body region such that the body contact plug is separated from the drift region by a section of the body region. 
     
     
         5 . The semiconductor device of  claim 1 , wherein the contact opening terminates within the body region, and wherein the first body contact region is formed in the body region. 
     
     
         6 . The semiconductor device of  claim 5 , wherein the source region is separated from the sidewalls by the body region, wherein at least part of the body region is uncovered by the electrically insulative spacer, and wherein the second body contact region adjoins the body contact plug along the part of the body region uncovered by the electrically insulative spacer. 
     
     
         7 . The semiconductor device of  claim 5 , wherein the source region is separated from the sidewalls by the body region, wherein at least part of the body region is uncovered by the electrically insulative spacer, and wherein the second body contact region adjoins the body contact plug along the part of the body region uncovered by the electrically insulative spacer. 
     
     
         8 . The semiconductor device of  claim 1 , wherein the contact opening extends through the body region, and wherein the first body contact region is formed in the drift region. 
     
     
         9 . The semiconductor device of  claim 8 , wherein the source region is separated from the sidewalls by the body region, wherein at least part of the body region is uncovered by the electrically insulative spacer, and wherein the second body contact region adjoins the body contact plug along the part of the body region uncovered by the electrically insulative spacer. 
     
     
         10 . The semiconductor device of  claim 1 , further comprising a drain region having the first conductivity type and formed at a second main surface of the semiconductor substrate opposite the first main surface, wherein the drain region is doped more heavily than the drift region. 
     
     
         11 . The semiconductor device of  claim 1 , further comprising a field plate in the trench below the gate electrode, wherein the field plate is electrically insulated from the gate electrode. 
     
     
         12 . The semiconductor device of  claim 1 , further comprising an interlayer dielectric on the first main surface of the semiconductor substrate, wherein the contact opening extends through the interlayer dielectric and into the semiconductor substrate, and wherein a width of the contact opening is larger in the interlayer dielectric than in the semiconductor substrate such that the electrically conductive material has a stepped profile in the contact opening. 
     
     
         13 . The semiconductor device of  claim 1 , further comprising an interlayer dielectric on the first main surface of the semiconductor substrate, wherein the contact opening extends through the interlayer dielectric and into the semiconductor substrate, and wherein the electrically insulative spacer extends onto the first main surface of the semiconductor substrate and along sidewalls of the interlayer dielectric formed by the contact opening. 
     
     
         14 . The semiconductor device of  claim 1 , wherein the electrically insulative spacer extends onto the first main surface of the semiconductor substrate. 
     
     
         15 . The semiconductor device of  claim 1 , wherein the electrically insulative spacer comprises oxide, nitride, carbon or tetraethoxysilane. 
     
     
         16 . A method of producing a semiconductor device, the method comprising:
 forming a trench that extends from a first main surface of a semiconductor substrate into the semiconductor substrate;   forming a gate electrode in the trench and insulated from the semiconductor substrate;   forming a source region having a first conductivity type in the semiconductor substrate at the first surface and adjacent the trench;   forming a body region having a second conductivity type in the semiconductor substrate below the first region and adjacent the trench;   forming a drift region having the first conductivity type in the semiconductor substrate below the second region and adjacent the trench;   forming a contact opening that extends through the source region and into the body region;   forming an electrically insulative spacer on sidewalls of the semiconductor substrate formed by the contact opening, wherein the electrically insulative spacer is recessed below the first main surface along the sidewalls such that at least part of the source region or body region is uncovered by the electrically insulative spacer;   forming a body contact plug in the contact opening;   forming a first body contact region having the second conductivity type in the semiconductor substrate adjacent a bottom of the contact opening, wherein the first body contact region adjoins the body contact plug at the bottom of the contact opening; and   forming a second body contact region having the second conductivity type in the part of the source region or body region uncovered by the electrically insulative spacer, wherein the second body contact region adjoins the body contact plug along the part of the source region or body region uncovered by the electrically insulative spacer.   
     
     
         17 . The method of  claim 16 , wherein the source region extends to the sidewalls, the method further comprising:
 removing the electrically insulative spacer from at least part of the source region,   wherein the second body contact region adjoins the body contact plug along the part of the source region from which the electrically insulative spacer was removed.   
     
     
         18 . The method of  claim 16 , wherein the source region is separated from the sidewalls by the body region, the method further comprising:
 removing the electrically insulative spacer from at least part of the body region,   wherein the second body contact region adjoins the body contact plug along the part of the body region from which the electrically insulative spacer was removed.   
     
     
         19 . The method of  claim 16 , further comprising:
 terminating the contact opening within the body region; and   forming the first body contact region in the body region.   
     
     
         20 . The method of  claim 16 , further comprising:
 extending the contact opening through the body region; and   forming the first body contact region in the drift region.