Image sensor and method for fabricating the same

Abstract

An image sensor includes a trench formed by a shallow trench isolation (STI) process, a channel stop layer formed over a substrate in the trench, an isolation structure filled in the trench, and a photodiode formed in the substrate adjacent to a sidewall of the trench. In more detail of the image sensor, a trench is formed in a substrate through a STI process, and a channel stop layer is formed over the substrate in the trench. An isolation structure is formed in the trench, and a photodiode is formed in the substrate adjacent to a sidewall of the trench.

What is claimed is: 
     
         1 . A method for fabricating an image sensor, the method comprising:
 forming a trench in a substrate;   forming a channel stop layer over an inner surface of the trench;   forming an isolation structure in the trench; and   forming a photodiode in the substrate.   
     
     
         2 . The method of  claim 1 , further comprising forming a thermal oxide layer over the channel stop layer prior to said forming an isolation structure in the trench. 
     
     
         3 . The method of  claim 1 , wherein said forming a channel stop layer comprises growing the channel stop layer as an epitaxial layer over the inner surface of the trench. 
     
     
         4 . The method of  claim 3 , wherein said growing the channel stop layer comprises doping the epitaxial layer with impurities of a conductivity type of the substrate during growth of the epitaxial layer. 
     
     
         5 . The method of  claim 3 , wherein said growing the channel stop layer comprises doping the epitaxial layer with boron impurities during growth of the epitaxial layer. 
     
     
         6 . The method of  claim 1 , wherein said forming an isolation structure comprises filling the trench with a high density plasma oxide layer. 
     
     
         7 . A method, comprising:
 forming a trench in a substrate;   forming a channel stop layer over an inner surface of the trench; and   forming an isolation structure in the trench.   
     
     
         8 . The method of  claim 7 , further comprising forming a thermal oxide layer over the channel stop layer prior to said forming an isolation structure in the trench. 
     
     
         9 . The method of  claim 7 , wherein said forming a channel stop layer comprises growing the channel stop layer as an epitaxial layer over the inner surface of the trench. 
     
     
         10 . The method of  claim 9 , wherein said growing the channel stop layer comprises doping the epitaxial layer with impurities of a conductivity type of the substrate during growth of the epitaxial layer. 
     
     
         11 . The method of  claim 9 , wherein said growing the channel stop layer comprises doping the epitaxial layer with boron impurities during growth of the epitaxial layer. 
     
     
         12 . The method of  claim 7 , wherein said forming an isolation structure comprises filling the trench with a high density plasma oxide layer. 
     
     
         13 . A method, comprising:
 forming an epitaxial channel stop layer over an inner surface of a trench in a substrate.   
     
     
         14 . The method of  claim 13 , further comprising forming an isolation structure in the trench. 
     
     
         15 . The method of  claim 13 , further comprising forming a photodiode in the substrate. 
     
     
         16 . The method of  claim 13 , further comprising:
 forming a thermal oxide layer over the epitaxial channel stop layer; and   forming an isolation structure in the trench.   
     
     
         17 . The method of  claim 13 , wherein said forming an epitaxial channel stop layer comprises growing the epitaxial channel stop layer over the inner surface of the trench. 
     
     
         18 . The method of  claim 13 , wherein said forming an epitaxial channel stop layer comprises doping the epitaxial channel stop layer with impurities of a conductivity type of the substrate during growth of the epitaxial channel stop layer. 
     
     
         19 . The method of  claim 13 , wherein said forming an epitaxial channel stop layer comprises doping the epitaxial channel stop layer with boron impurities during growth of the epitaxial channel stop layer. 
     
     
         20 . The method of  claim 13 , further comprising filling the trench with a high density plasma oxide layer.