Ti-capping technique as a breakthrough for achieving low threshold voltage, high mobility, and high reliability of pMOSFET with metal gate and high-k dielectrics technologies

We have proposed inhibition mechanism of common Al-capping technique for pMOSFET threshold-voltage (V_th) control for the first time, and have established effective Ti-capping technique using metal gate and Hf-based high-k dielectrics. Ti-capping technique can adjust lower V_th than Al-capping one due to the suppression of counter dipole and solid solubility limit in doping. Moreover, Ti-capping technique can improve carrier mobility and negative bias temperature instability (NBTI). We have confirmed that Ti-doped devices achieve higher performance, and the technique is suitable for 32 nm-technology node and beyond.