Adjusting of strain caused in a transistor channel by semiconductor material provided for the threshold adjustment

Abstract

The threshold voltage of a sophisticated transistor may be adjusted by providing a specifically designed semiconductor alloy in the channel region of the transistor, wherein a negative effect of this semiconductor material with respect to inducing a strain component in the channel region may be reduced or over-compensated for by additionally incorporating a strain-adjusting species. For example, a carbon species may be incorporated in the channel region, the threshold voltage of which may be adjusted on the basis of a silicon/germanium alloy of a P-channel transistor. Consequently, sophisticated metal gate electrodes may be formed in an early manufacturing stage.

1 .- 20 . (canceled) 
     
     
         21 . A transistor, comprising:
 a silicon-containing semiconductor region formed above a substrate;   a gate electrode structure formed above said silicon-containing semiconductor region, said gate electrode structure comprising a high-k gate insulation layer and a metal-containing electrode material formed on said high-k gate insulation layer; and   a channel region comprising a threshold-adjusting semiconductor material comprising a first tetravalent non-silicon species that is in contact with said high-k gate insulation layer, said channel region further comprising a strain adjustment tetravalent non-silicon species that is different from a said first non-silicon species.   
     
     
         22 . The transistor of  claim 21 , wherein said strain adjustment species is carbon. 
     
     
         23 . The transistor of  claim 21 , wherein said first non-silicon species comprises germanium. 
     
     
         24 . The transistor of  claim 23 , wherein a concentration of said first non-silicon species is approximately 20 atomic percent or more. 
     
     
         25 . The transistor of  claim 24 , wherein a concentration of said strain-adjusting species is approximately one atomic percent or more. 
     
     
         26 . A transistor, comprising:
 a silicon-containing semiconductor region formed above a substrate;   a gate electrode structure formed above said silicon-containing semiconductor region, said gate electrode structure comprising a high-k gate insulation layer and a metal-containing electrode material formed above said high-k gate insulation layer; and   a channel region comprising a threshold-adjusting semiconductor material that is in contact with said high-k gate insulation layer and carbon, wherein said threshold-adjusting semiconductor material is comprised of germanium.   
     
     
         27 . The transistor of  claim 26 , wherein a concentration of said germanium is approximately 20 atomic percent or more. 
     
     
         28 . The transistor of  claim 26 , wherein a concentration of said carbon is approximately one atomic percent or more. 
     
     
         29 . A transistor, comprising:
 a silicon-containing semiconductor region formed above a substrate;   a gate electrode structure formed above said silicon-containing semiconductor region, said gate electrode structure comprising a high-k gate insulation layer and a metal-containing electrode material formed above said high-k gate insulation layer; and   a channel region comprising a threshold-adjusting semiconductor material that is that is in contact with said high-k gate insulation layer and carbon, wherein said threshold-adjusting semiconductor material is comprised of at least 20 atomic percent of germanium and wherein a concentration of said carbon is at least one atomic percent.