Semiconductor device and method of forming the same

Abstract

The present invention provides a cylindrically shaped stack electrode having a lamination structure which comprises a cylindrically shaped outer layer and a cylindrically shaped inner layer laminated on an inner wall of said cylindrically shaped outer layer, wherein hemispherical grains are formed on an inner wall of said cylindrically shaped inner layer. The cylindrically shaped stack electrode has the lamination structure of a plurality of layers.

What is claimed is:  
     
         1 . A cylindrically shaped stack electrode having a lamination structure which comprises a cylindrically shaped outer layer and a cylindrically shaped inner layer laminated on an inner wall of said cylindrically shaped outer layer, wherein hemispherical grains are formed on an inner wall of said cylindrically shaped inner layer.  
     
     
         2 . The cylindrically shaped stack electrode as claimed in  claim 1 , further comprising an additional stopper layer on an inner wall of the cylindrically shaped outer layer, wherein the additional stopper layer is effective to stop crystal grains from reaching the cylindrically shaped outer layer.  
     
     
         3 . The cylindrically shaped stack electrode as claimed in  claim 1 , further comprising an additional stopper layer between the cylindrically shaped outer layer and the cylindrically shaped inner layer, wherein the additional stopper layer is effective to stop crystal grains from reaching the cylindrically shaped outer layer.  
     
     
         4 . The cylindrically shaped stack electrode as claimed in  claim 1 , wherein the cylindrically shaped inner layer comprises an amorphous silicon layer with the inner wall having hemispherical grains, whilst the cylindrically shaped outer layer comprises a polysilicon layer.  
     
     
         5 . A stacked capacitor which comprises a cylindrically shaped stack electrode, a capacitive insulation film and a surface side opposite electrode, wherein the cylindrically shaped stack electrode has a lamination structure which comprises a cylindrically shaped outer layer and a cylindrically shaped inner layer laminated on an inner wall of said cylindrically shaped outer layer, wherein hemispherical grains are formed on an inner wall of said cylindrically shaped inner layer.  
     
     
         6 . The stacked capacitor as claimed in  claim 5 , further comprising an additional stopper layer on an inner wall of the cylindrically shaped outer layer, wherein the additional stopper layer is effective to stop crystal grains from reaching the cylindrically shaped outer layer.  
     
     
         7 . The stacked capacitor as claimed in  claim 5 , further comprising an additional stopper layer between the cylindrically shaped outer layer and the cylindrically shaped inner layer, wherein the additional stopper layer is effective to stop crystal grains from reaching the cylindrically shaped outer layer.  
     
     
         8 . The stacked capacitor as claimed in  claim 5 , wherein the cylindrically shaped inner layer comprises an amorphous silicon layer with the inner wall having hemispherical grains, whilst the cylindrically shaped outer layer comprises a polysilicon layer.  
     
     
         9 . A method of forming a cylindrically shaped stack electrode having a lamination structure, the method comprising the steps of: 
 forming a cylindrically shaped outer layer;    forming a cylindrically shaped inner layer laminated on an inner wall of the cylindrically shaped outer layer; and    forming hemispherical grains on an inner wall of said cylindrically shaped inner layer.    
     
     
         10 . The method as claimed in  claim 9 , further comprising a step of: 
 forming an additional stopper layer on an inner wall of the cylindrically shaped outer layer, wherein the additional stopper layer is effective to stop crystal grains from reaching the cylindrically shaped outer layer.    
     
     
         11 . The method as claimed in  claim 9 , further comprising a step of: 
 forming an additional stopper layer between the cylindrically shaped outer layer and the cylindrically shaped inner layer, wherein the additional stopper layer is effective to stop crystal grains from reaching the cylindrically shaped outer layer.    
     
     
         12 . The method as claimed in  claim 9 , wherein the cylindrically shaped inner layer comprises an amorphous silicon layer with the inner wall having hemispherical grains, whilst the cylindrically shaped outer layer comprises a polysilicon layer.  
     
     
         13 . A method of forming a stacked capacitor, comprising the steps of: 
 forming a cylindrically shaped outer layer;    forming a cylindrically shaped inner layer laminated on an inner wall of the cylindrically shaped outer layer; and    forming hemispherical grains on an inner wall of the cylindrically shaped inner layer to form a cylindrically shaped stack electrode, forming a capacitive insulation film on a surface of the cylindrically shaped stack electrode, and forming a surface side opposite electrode on the capacitive insulation film.    
     
     
         14 . The method as claimed in  claim 13 , further comprising a step of: 
 forming an additional stopper layer on an inner wall of the cylindrically shaped outer layer, wherein the additional stopper layer is effective to stop crystal grains from reaching the cylindrically shaped outer layer.    
     
     
         15 . The method as claimed in  claim 13 , further comprising a step of: 
 forming an additional stopper layer between the cylindrically shaped outer layer and the cylindrically shaped inner layer, wherein the additional stopper layer is effective to stop crystal grains from reaching the cylindrically shaped outer layer.    
     
     
         16 . The method as claimed in  claim 13 , wherein the cylindrically shaped inner layer comprises an amorphous silicon layer with the inner wall having hemispherical grains, whilst the cylindrically shaped outer layer comprises a polysilicon layer.