Semiconductor device and manufacturing method thereof

Abstract

In a thin film transistor, a metallic element promoting crystallization of an amorphous silicon film is effectively removed and the productivity is improved. By using a silicon film containing an element belonging to the group 15 such as phosphorus through contact holes reaching a source region and a drain region, a metallic element promoting crystallization of an amorphous silicon film can be effectively removed or decreased and the productivity can be improved.

What is claimed is:  
     
         1 . A semiconductor device comprising: 
 a substrate having an insulating surface;    a crystalline semiconductor film formed over the insulating surface, the crystalline semiconductor film having a source region, a drain region, and a channel forming region sandwiched between the source region and the drain region;    a gate insulating film formed on the crystalline semiconductor film;    a gate electrode formed on the gate insulating film;    an interlayer insulating film formed on the gate electrode;    a film containing an impurity element belonging to the group 15 of the periodic table formed on the interlayer insulating film; and    a conductive layer formed on the film containing an impurity element belonging to the group 15 of the periodic table,    wherein the film containing the impurity element belonging to the group 15 of the periodic table is in contact with the source region or the drain region of the crystalline semiconductor film in a contact hole formed in the interlayer insulating film, and    wherein a metallic element used in forming the crystalline semiconductor film segregates in the film containing the impurity element belonging to the group 15 of the periodic table.    
     
     
         2 . A device according to  claim 1 , wherein said semiconductor film comprises silicon.  
     
     
         3 . A device according to  claim 1 , wherein the film containing the impurity element belonging to the group 15 of the periodic table comprises silicon.  
     
     
         4 . A device according to  claim 1 , wherein the metallic element for promoting crystallization of the semiconductor film is one or more elements selected from the group consisting of Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Au, Ge, Pb and In.  
     
     
         5 . A device according to  claim 1 , wherein the impurity element contained in the film containing the impurity element belonging to the group 15 of the periodic table is phosphorus.  
     
     
         6 . A device according to  claim 1 , wherein the concentration of the impurity element belonging to the group 15 of the periodic table in the film is 1×10 19  atoms/cm 3  or more.  
     
     
         7 . A semiconductor device comprising: 
 a gate electrode formed on an insulating surface;    a gate insulating film formed on the gate electrode;    a crystalline semiconductor film formed on the gate insulating film, the crystalline semiconductor film having a source region, a drain region, and a channel forming region sandwiched between the source region and the drain region;    a protective insulating film formed on the crystalline semiconductor film;    an interlayer insulating film formed on the protective insulating film;    a film containing an impurity element belonging to the group 15 of the periodic table formed on the interlayer insulating film, and    a conductive layer formed on the film containing an impurity element belonging to the group 15 of the periodic table,    wherein the film containing the impurity element belonging to the group 15 of the periodic table is in contact with the source region or the drain region of the crystalline semiconductor film in a contact hole formed in the interlayer insulating film, and    wherein a metallic element required in forming the crystalline semiconductor film segregates in the film containing the impurity element belonging to the group 15 of the periodic table.    
     
     
         8 . A device according to  claim 7 , wherein said semiconductor film comprises silicon.  
     
     
         9 . A device according to  claim 7 , wherein the film containing the impurity element belonging to the group 15 of the periodic table comprises silicon.  
     
     
         10 . A device according to  claim 7 , wherein the metallic element promoting crystallization of the semiconductor film is one or more elements selected from the group consisting of Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Au, Ge, Pb and In.  
     
     
         11 . A device according to  claim 7 , wherein the impurity element contained in the film containing the impurity element belonging to the group 15 of the periodic table is phosphorus.  
     
     
         12 . A device according to  claim 7 , wherein the concentration of the impurity element belonging to the group 15 of the periodic table in the film is 1×1019 atoms/cm 3  or more.  
     
     
         13 . A semiconductor device comprising: 
 a crystalline semiconductor film formed over a substrate, the crystalline semiconductor film having at least a source region, a drain region, and a channel forming region;    a gate insulating film formed on the crystalline semiconductor film;    a gate electrode formed on the gate insulating film;    an interlayer insulating film formed on the gate electrode; and    multilayer source and drain electrodes comprising first and second conductive layers, said first conductive layer comprising a semiconductor film and containing an impurity element belonging to the group 15 of the periodic table and a metallic element for promoting crystallization of said semiconductor film,    wherein the first conductive layer is in contact with the source region or the drain region of the crystalline semiconductor film in a contact hole formed in the interlayer insulating film.    
     
     
         14 . A device according to  claim 13 , wherein said semiconductor film comprises silicon.  
     
     
         15 . A device according to  claim 13 , wherein the first conductive layer comprises silicon.  
     
     
         16 . A device according to  claim 13 , wherein the metallic element is one or more elements selected from the group consisting of Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Au, Ge, Pb and In.  
     
     
         17 . A device according to  claim 13 , wherein the impurity element contained in the first conductive layer is phosphorus.  
     
     
         18 . A device according to  claim 13 , wherein the concentration of the impurity element belonging to the group 15 of the periodic table in the first conductive layer is 1×10 19  atoms/cm 3  or more.  
     
     
         19 . A semiconductor device comprising: 
 a gate electrode formed on an insulating surface;    a gate insulating film formed on the gate electrode;    a crystalline semiconductor film formed on the gate insulating film, the crystalline semiconductor film having a source region, a drain region, and a channel forming region;    a protective insulating film formed on the crystalline semiconductor film;    an interlayer insulating film formed on the protective insulating film; and    multilayer source and drain electrodes comprising first and second conductive layers, said first conductive layer comprising a semiconductor film and containing an impurity element belonging to the group 15 of the periodic table and a metallic element for promoting crystallization of said semiconductor film,    wherein the first conductive layer is in contact with the source region or the drain region of the crystalline semiconductor film in a contact hole formed in the interlayer insulating film.    
     
     
         20 . A device according to  claim 19 , wherein said semiconductor film comprises silicon.  
     
     
         21 . A device according to  claim 19 , wherein the first conductive layer comprises silicon.  
     
     
         22 . A device according to  claim 19 , wherein the metallic element is one or more elements selected from the group consisting of Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Au, Ge, Pb and In.  
     
     
         23 . A device according to  claim 19 , wherein the impurity element contained in the first conductive layer is phosphorus.  
     
     
         24 . A device according to  claim 19 , wherein the concentration of the impurity element belonging to the group 15 of the periodic table in the first conductive layer is 1×10 19  atoms/cm 3  or more.  
     
     
         25 . A method of manufacturing a semiconductor device comprising the steps of: 
 forming a base insulating film on a substrate;    forming an amorphous semiconductor film on the base insulating film;    doping a metallic element promoting crystallization of the amorphous semiconductor film and crystallizing the amorphous semiconductor film to form a crystalline semiconductor film;    forming a gate insulating film on the crystalline semiconductor film;    forming a gate electrode on the gate insulating film;    doping an impurity element in a selected region of the crystalline semiconductor film to form a source region and a drain region;    forming an interlayer insulating film on the gate electrode;    forming a contact hole in the interlayer insulating film, the contact hole reaching the source region or the drain region;    forming a film containing an impurity element belonging to the group 15 of the periodic table in the contact hole reaching the source region or the drain region and on the interlayer insulating film;    gettering by thermal annealing the metallic element contained in the crystalline semiconductor film; and    forming a conductive film on the film containing an impurity element belonging to the group 15 of the periodic table.    
     
     
         26 . A method according to  claim 25 , wherein said semiconductor film comprises silicon.  
     
     
         27 . A method according to  claim 25 , wherein the film containing an impurity element belonging to the group 15 of the periodic table comprises silicon.  
     
     
         28 . A method according to  claim 25 , wherein the thermal annealing progresses gettering of the metallic element promoting crystallization of the amorphous semiconductor film.  
     
     
         29 . A method according to claims  25 , wherein thermal annealing not only progresses gettering of the metallic element promoting crystallization of the amorphous semiconductor film but also activates the impurity element doped in the crystallized semiconductor film.  
     
     
         30 . A method according to  claim 25 , wherein the metallic element promoting crystallization of the amorphous semiconductor film is one or more elements selected from the group consisting of Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Au, Ge, Pb, and In.  
     
     
         31 . A method according to  claim 25 , wherein the impurity element contained in a film containing an impurity element belonging to the group 15 of the periodic table is phosphorus.  
     
     
         32 . A method according to  claim 25 , wherein the concentration of an impurity element belonging to the group 15 of the periodic table in the film is 1×10 19  atoms/cm 3  or more.  
     
     
         33 . A method according to  claim 25 , wherein the film containing an impurity element belonging to the group 15 of the periodic table is patterned using the conductive film in a self-aligning manner to function as wiring.  
     
     
         34 . A method of manufacturing a semiconductor device comprising the steps of: 
 forming a gate electrode on the insulating surface;    forming a gate insulating film on the gate electrode;    forming an amorphous semiconductor film on the gate insulating film;    doping a metallic element promoting crystallization of the amorphous semiconductor film and crystallizing the amorphous semiconductor film to form a crystalline semiconductor film;    forming a protective insulating film on the crystalline semiconductor film;    doping an impurity element in a selected region of the crystalline semiconductor film to form a source region and a drain region;    forming an interlayer insulating film on the protective insulating film;    forming a contact hole in the protective insulating film and the interlayer insulating film, the contact hole reaching the source region or the drain region;    forming a film containing an impurity element belonging to the group 15 of the periodic table in the contact hole reaching the source region or the drain region and on the interlayer insulating film;    gettering by thermal annealing the metallic element contained in the crystalline semiconductor film; and    forming a conductive film on the film containing an impurity element belonging to the group 15 of the periodic table.    
     
     
         35 . A method according to  claim 34 , wherein said semiconductor film comprises silicon.  
     
     
         36 . A method according to  claim 34 , wherein the film containing an impurity element belonging to the group 15 of the periodic table comprises silicon.  
     
     
         37 . A method according to  claim 34 , wherein the thermal annealing progresses gettering of the metallic element promoting crystallization of the amorphous semiconductor film.  
     
     
         38 . A method according to claims  34 , wherein thermal annealing not only progresses gettering of the metallic element promoting crystallization of the amorphous semiconductor film but also activates the impurity element doped in the crystallized semiconductor film.  
     
     
         39 . A method according to  claim 34 , wherein the metallic element promoting crystallization of the amorphous semiconductor film is one or more elements selected from the group consisting of Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Au, Ge, Pb, and In.  
     
     
         40 . A method according to  claim 34 , wherein the impurity element contained in a film containing an impurity element belonging to the group 15 of the periodic table is phosphorus.  
     
     
         41 . A method according to  claim 34 , wherein the concentration of an impurity element belonging to the group 15 of the periodic table in the film is 1×10 19  atoms/cm 3  or more.  
     
     
         42 . A method according to  claim 34 , wherein the film containing an impurity element belonging to the group 15 of the periodic table is patterned using the conductive film in a self-aligning manner to function as wiring.