High performance pMOSFETs with Ni(Si/sub x/Ge/sub 1-x/)/poly-Si/sub 0.8/Ge/sub 0.2/ gate

For the first time, Ni salicide process is applied directly on poly-Si/sub 0.8/Ge/sub 0.2/ gate, and pMOSFETs utilizing Ni(Si/sub x/Ge/sub 1-x/)/poly-Si/sub 0.8/Ge/sub 0.2/ gate are fully characterized. The excellent value (/spl sim/5/spl Omega///spl square/) of sheet resistance is achieved from 0.15 /spl mu/m Ni(Si/sub x/Ge/sub 1-x/)/Si/sub 0.8/Ge/sub 0.2/ gate, while Co salicide process applied on Si/sub 0.8/Ge/sub 0.2/ gate results in R/sub s/ fail due to Ge segregation. It is also important to note that, with poly-Si/sub 0.8/Ge/sub 0.2/ gate and Ni salicide process, the current drivability of pMOSFETs is significantly improved due to less gate poly depletion and lower source-to-drain resistance (R/sub sd/). Conclusively, Ni salicide is the exclusive process for successful germanosilicide formation on poly-Si/sub 0.8/Ge/sub 0.2/ gate without poly-Si buffer layer and Ni(Si/sub x/Ge/sub 1-x/)/poly-Si/sub 0.8/Ge/sub 0.2/ gate can increase L/sub dsat/ of pMOSFETs by 20% as compared to conventional CoSi/sub 2//poly-Si gate structure.