Method of Manufacturing a Semiconductor Device by Plasma Doping

Abstract

A method of manufacturing a semiconductor device includes forming a superjunction field effect transistor by: forming trenches in a semiconductor body from a first side: forming charge compensation layers by doping parts of the semiconductor body via sidewalls of the trenches by introducing dopants by plasma doping; after forming the charge compensation layers, widening a profile of the dopants introduced by plasma doping by diffusion caused by a thermal heating process; and forming a drain contact at a second side opposite to the first side. A surface concentration of the dopants introduced by plasma doping via a unit area of the sidewalls is at least five times larger than a concentration of dopants in a mesa region of the semiconductor body between neighboring trenches which corresponds to N, wherein N is a net doping of the semiconductor body between the neighboring trenches.

What is claimed is: 
     
         1 . A method of manufacturing a semiconductor device, the method comprising:
 forming a superjunction field effect transistor by:   forming trenches in a semiconductor body from a first side;   forming charge compensation layers by doping parts of the semiconductor body via sidewalls of the trenches by introducing dopants by plasma doping;   after forming the charge compensation layers, widening a profile of the dopants introduced by plasma doping by diffusion caused by a thermal heating process; and   forming a drain contact at a second side opposite to the first side,   wherein a surface concentration of the dopants introduced by plasma doping via a unit area of the sidewalls is at least five times larger than a concentration of dopants in a mesa region of the semiconductor body between neighboring trenches which corresponds to N, wherein N is a net doping of the semiconductor body between the neighboring trenches.   
     
     
         2 . The method of  claim 1 , wherein the semiconductor body is a silicon semiconductor body. 
     
     
         3 . The method of  claim 1 , wherein the semiconductor body is a silicon carbide semiconductor body. 
     
     
         4 . The method of  claim 1 , wherein doping parts of the semiconductor body by plasma doping comprises adjusting a DC-voltage pulse distance in a range of 100 μs to 10 ms. 
     
     
         5 . The method of  claim 1 , wherein doping parts of the semiconductor body by plasma doping comprises adjusting a DC-voltage pulse width in a range of 0.5 μs to 20 μs. 
     
     
         6 . The method of  claim 1 , further comprising filling the trenches with an insulating material. 
     
     
         7 . The method of  claim 1 , further comprising filling the trenches with a semiconductor material. 
     
     
         8 . The method of  claim 1 , further comprising forming a first semiconductor layer on the doped parts of the semiconductor body. 
     
     
         9 . The method of  claim 8 , wherein forming the first semiconductor layer on the doped parts of the semiconductor body comprises forming a silicon layer by lateral epitaxy or low-temperature chemical vapor deposition. 
     
     
         10 . The method of  claim 8 , wherein forming the first semiconductor layer on the doped parts of the semiconductor body comprises:
 forming an amorphous silicon layer on the doped parts of the semiconductor body: and   crystallizing the amorphous silicon layer by a heat treatment.   
     
     
         11 . The method of  claim 1 , further comprising forming an outdiffusion barrier layer on the sidewalls of the trenches. 
     
     
         12 . The method of  claim 1 , wherein the semiconductor body includes a drift zone of a first conductivity type, and wherein doping parts of the semiconductor body by plasma doping comprises doping the parts of the semiconductor body with dopants of a second conductivity type complementary to the first conductivity type. 
     
     
         13 . The method of  claim 1 , wherein the semiconductor body includes a drift zone of a first conductivity type, and wherein doping parts of the semiconductor body by plasma doping comprises doping the parts of the semiconductor body with dopants of the first conductivity type, the method further comprising:
 forming a first semiconductor layer over the parts of the semiconductor body in the trenches; and   doping the first semiconductor layer by plasma doping with dopants of a second conductivity type complementary to the first conductivity type.   
     
     
         14 . The method of  claim 13 , further comprising:
 removing the first semiconductor layer from a bottom side of the trenches;   forming a second semiconductor layer over the first semiconductor layer in the trenches; and   doping the second semiconductor layer by plasma doping with dopants of the first conductivity type.   
     
     
         15 . The method of  claim 1 , further comprising forming body regions in the semiconductor body at the first side, the body regions overlapping the charge compensation layers. 
     
     
         16 . A method of manufacturing a semiconductor device, the method comprising:
 forming trenches in a semiconductor body from a first side:   doping parts of the semiconductor body via sidewalls of the trenches by introducing dopants by plasma doping; and   after introducing the dopants by plasma doping, widening a profile of the dopants introduced by plasma doping by diffusion caused by a thermal heating process,   wherein a surface concentration of the dopants introduced by plasma doping via a unit area of the sidewalls is at least five times larger than a concentration of dopants in a mesa region of the semiconductor body between neighboring trenches which corresponds to N, wherein N is a net doping of the semiconductor body between the neighboring trenches.   
     
     
         17 . The method of  claim 16 , wherein the semiconductor body includes a drift zone of a first conductivity type, and wherein doping parts of the semiconductor body by plasma doping comprises doping the parts of the semiconductor body with dopants of a second conductivity type complementary to the first conductivity type. 
     
     
         18 . The method of  claim 16 , wherein the semiconductor body includes a drift zone of a first conductivity type, and wherein doping parts of the semiconductor body by plasma doping comprises doping the parts of the semiconductor body with dopants of the first conductivity type, the method further comprising:
 forming a first semiconductor layer over the parts of the semiconductor body in the trenches; and   doping the first semiconductor layer by plasma doping with dopants of a second conductivity type complementary to the first conductivity type.   
     
     
         19 . The method of  claim 18 , further comprising:
 removing the first semiconductor layer from a bottom side of the trenches;   forming a second semiconductor layer over the first semiconductor layer in the trenches; and   doping the second semiconductor layer by plasma doping with dopants of the first conductivity type.   
     
     
         20 . The method of  claim 16 , wherein the semiconductor body is a silicon carbide semiconductor body.