Gate structures for semiconductor devices with a conductive etch stop layer

Abstract

One illustrative gate structure of a transistor device disclosed herein includes a high-k gate insulation layer and a work function metal layer positioned on the high-k gate insulation layer. The device further includes a first bulk metal layer positioned on the work function metal layer. The device further includes a second bulk metal layer. The first and second bulk metal layers have upper surfaces that are at substantially the same height level, and the first and second bulk metal layers are made of substantially the same material. The device further includes a conductive etch stop layer between the first and second bulk metal layers.

What is claimed: 
     
         1 . A gate structure of a transistor device, comprising:
 a high-k gate insulation layer;   a work function metal layer positioned on said high-k gate insulation layer;   a first bulk metal layer positioned on said work function metal layer;   a second bulk metal layer, said first and second bulk metal layers comprising upper surfaces that are at substantially the same height level; and   a conductive etch stop layer positioned between said first and second bulk metal layers.   
     
     
         2 . The device of  claim 1 , further comprising a gate cap layer above said conductive etch stop layer. 
     
     
         3 . The device of  claim 1 , wherein said conductive etch stop layer comprises a material selected from the group consisting of titanium, titanium nitride, tantalum, tantalum nitride, tungsten nitride, aluminum, ruthenium, titanium silicon nitride and tantalum silicon nitride. 
     
     
         4 . The device of  claim 1 , wherein said first and second bulk metal layers comprise tungsten. 
     
     
         5 . The device of  claim 1 , wherein said first and second bulk metal layers are made of the same material. 
     
     
         6 . The device of  claim 1 , wherein said first bulk metal layer comprises a different material than said second bulk metal layer. 
     
     
         7 . The device of  claim 1 , wherein said work function metal layer comprises titanium nitride. 
     
     
         8 . The device of  claim 1 , wherein said work function metal layer and said conductive etch stop layer are made of the same material. 
     
     
         9 . The device of  claim 1 , further comprising a gate cap layer that is positioned on and in contact with an upper surface of said first bulk metal layer, an upper surface of said conductive etch stop layer and an upper surface of said second bulk metal layer. 
     
     
         10 . The device of  claim 1 , wherein an upper surface of said first bulk metal layer, an upper surface of said conductive etch stop layer and an upper surface of said second bulk metal layer are all positioned in a common horizontal plane 
     
     
         11 . The device of  claim 1 , wherein said conductive etch stop layer comprises a material selected from the group consisting of titanium, titanium nitride, tantalum, tantalum nitride, tungsten nitride, aluminum, ruthenium, titanium silicon nitride and tantalum silicon nitride. 
     
     
         12 . The device of  claim 11 , wherein said first bulk metal layer and said second bulk metal layer comprise tungsten. 
     
     
         13 . The device of  claim 1 , wherein, in a cross-section taken through said gate structure in a direction that is parallel to a gate length direction of said transistor device:
 each of said high-k gate insulation layer, said work function metal layer, said first bulk metal layer, and said conductive etch stop layer have a generally U-shaped cross-sectional configuration; and   said second bulk metal layer has a generally rectangular cross-sectional configuration, and said second bulk metal layer is bounded on three sides by said generally U-shaped conductive etch stop layer.   
     
     
         14 . A gate structure of a transistor device, comprising:
 a high-k gate insulation layer;   a work function metal layer positioned on said high-k gate insulation layer, said work function metal layer comprising an upper surface;   a first bulk metal layer positioned on said work function metal layer, said first bulk metal layer comprising an upper surface;   a second bulk metal layer, said second bulk metal layer comprising an upper surface;   a conductive etch stop layer positioned between said first and second bulk metal layers, said conductive etch stop layer comprising an upper surface, wherein said upper surfaces of said conductive etch stop layer, said work function metal layer, said first bulk metal layer and said second bulk metal layer are positioned at substantially the same height level above an upper surface of a semiconductor substrate; and   a gate cap layer that is positioned on and in contact with said upper surfaces of said first bulk metal layer, said conductive etch stop layer and said second bulk metal layer.   
     
     
         15 . The device of  claim 14 , wherein said first and second bulk metal layers are made of the same material. 
     
     
         16 . The device of  claim 14 , wherein said first bulk metal layer comprises a different material than said second bulk metal layer. 
     
     
         17 . The device of  claim 14 , wherein said work function metal layer and said conductive etch stop layer are made of the same material. 
     
     
         18 . The device of  claim 15 , wherein, in a cross-section taken through said gate structure in a direction that is parallel to a gate length direction of said transistor device:
 each of said high-k gate insulation layer, said work function metal layer, said first bulk metal layer, and said conductive etch stop layer have a generally U-shaped cross-sectional configuration; and   said second bulk metal layer has a generally rectangular cross-sectional configuration, and said second bulk metal layer is bounded on three sides by said generally U-shaped conductive etch stop layer.   
     
     
         19 . An integrated circuit device, comprising:
 a gate structure of a short channel device comprising:
 a first high-k gate insulation layer comprising a high-k material; 
 a first work function metal layer positioned on said first high-k gate insulation layer, said first work function metal layer comprising a work function metal material; and 
 a first bulk metal layer positioned on said first work function metal layer, said first bulk metal layer comprising a bulk metal material; and 
   a gate structure of a long channel device comprising:
 a second high-k gate insulation layer comprising said high-k material; 
 a second work function metal layer positioned on said second high-k gate insulation layer, said second work function metal layer comprising said work function metal material; 
 another first bulk metal layer positioned on said second work function metal layer, said another bulk metal layer comprising said bulk metal material; 
 a second bulk metal layer; and 
 a conductive etch stop layer positioned between said another first bulk metal layer and said second bulk metal layer. 
   
     
     
         20 . The device of  claim 19 , further comprising:
 a first gate cap layer for said short channel device, wherein said first gate cap layer is positioned on and in contact with an upper surface of said first work function metal layer and an upper surface of said first bulk metal layer of said first gate structure; and   a second gate cap layer for said long channel device, wherein the second gate cap layer is positioned on and in contact with an upper surface of said another first bulk metal layer, an upper surface of said conductive etch stop layer and an upper surface of said second bulk metal layer of said second gate structure.   
     
     
         21 . The device of  claim 19 , wherein said another first bulk metal layer and said second bulk metal layer of said second gate structure are made of the same material. 
     
     
         22 . The device of  claim 19 , wherein said another first bulk metal layer and said second bulk metal layer of said second gate structure are made of different materials. 
     
     
         23 . The device of  claim 21 , wherein said work function metal material comprises titanium nitride. 
     
     
         24 . The device of  claim 19 , wherein said second work function metal layer and said conductive etch stop layer of said second gate structure are made of the same material. 
     
     
         25 . The device of  claim 19 , wherein an upper surface of said another first bulk metal layer, an upper surface of said conductive etch stop layer and an upper surface of said second bulk metal layer of said second gate structure are all positioned in a common horizontal plane. 
     
     
         26 . The device of  claim 19 , wherein, in a cross-section taken through said second gate structure in a direction that is parallel to a gate length direction of said long channel device:
 each of said second high-k gate insulation layer, said second work function metal layer, said another first bulk metal layer, and said conductive etch stop layer of said second gate structure have a generally U-shaped cross-sectional configuration; and   said second bulk metal layer of said second gate structure has a generally rectangular cross-sectional configuration, and said second bulk metal layer is bounded on three sides by said generally U-shaped conductive etch stop layer.