Semiconductor device including a channel stop structure and method of manufacturing the same

Abstract

It is an object to obtain a semiconductor device comprising a channel stop structure which is excellent in an effect of stabilizing a breakdown voltage and a method of manufacturing the semiconductor device. A silicon oxide film ( 2 ) is formed on an upper surface of an N − -type silicon substrate ( 1 ). An N + -type impurity implantation region ( 4 ) is formed in an upper surface ( 3 ) of the N − -type silicon substrate ( 1 ) in a portion exposed from the silicon oxide film ( 2 ). A deeper trench ( 5 ) than the N + -type impurity implantation region ( 4 ) is formed in the upper surface ( 3 ) of the N − -type silicon substrate ( 1 ). A silicon oxide film ( 6 ) is formed on an inner wall of the trench ( 5 ). A polysilicon film ( 7 ) is formed to fill in the trench ( 5 ). An aluminum electrode ( 8 ) is formed on the upper surface ( 3 ) of the N − -type silicon substrate ( 1 ). The aluminum electrode ( 8 ) is provided in contact with an upper surface of the polysilicon film ( 7 ) and the upper surface ( 3 ) of the N − -type silicon substrate ( 1 ). The aluminum electrode ( 8 ) is extended over the silicon oxide film ( 2 ) to constitute a field plate.

1 . A semiconductor device comprising: 
 an N-type semiconductor substrate;    a transistor having a first impurity introduced region of P-type formed in a main surface of said semiconductor substrate and constituting a main junction together with said semiconductor substrate; and    a channel stop structure formed in a peripheral portion of said semiconductor substrate, said channel stop structure including,    a first conductive film,    a second conductive film formed on said main surface of said semiconductor substrate and on said first conductive film, said second conductive film including a material different from that of said first conductive film and extending toward said main junction,    a first trench formed in said main surface of said semiconductor substrate, and    a second impurity introduced region of N-type formed in said main surface of said semiconductor substrate in a portion where said first trench is formed and directly contacting said first trench,    wherein said first trench is filled with said first conductive film, and a portion of said first conductive film is formed on said main surface of said semiconductor substrate said portion of said first conductive film extending toward said main junction.    
   
   
       2 . (canceled)  
   
   
       3 . The semiconductor device according to  claim 1 , wherein said channel stop structure further has: 
 a first insulating film formed on an inner wall of said first trench.    
   
   
       4 . (canceled)  
   
   
       5 . The semiconductor device according to  claim 3 , wherein a material of said first conductive film is polysilicon.  
   
   
       6 . (canceled)  
   
   
       7 . The semiconductor device according to  claim 3 , wherein said transistor further has: 
 a third impurity introduced region of N-type formed in said main surface of said semiconductor substrate and functioning as a source or an emitter of said transistor;    a second trench formed in said main surface of said semiconductor substrate in a portion where said third impurity introduced region is formed;    a second insulating film formed on an inner wall of said second trench and functioning as a gate insulating film of said transistor; and    a third conductive film formed to fill in said second trench and functioning as a gate electrode of said transistor, and wherein    said channel stop structure further has a fourth impurity introduced region of P-type formed in said main surface of said semiconductor substrate.    
   
   
       8 . The semiconductor device according to  claim 7 , wherein an opening width of said first trench is equal to that of said second trench.  
   
   
       9 . The semiconductor device according to  claim 7 , wherein a material of said first conductive film is equal to that of said third conductive film.  
   
   
       10 - 19 . (canceled)  
   
   
       20 . The semiconductor device according to  claim 1 , wherein said portion of said first conductive film directly contacts said second impurity introduced region.