Abstract
Traditional transistor processes use poly-Si as gate material for decades. However, aggressive scaling of channel length and gate oxide thickness in a conventional transistor aggravates the problems of poly-silicon (poly-Si) gate depletion, high gate resistance, high gate tunneling leakage current, and boron penetration into the channel region. As a result, there is immense interest in metal gates and alternative gate dielectrics with higher permittivity. In this work we developed a good metal gate with high work function and acceptable electrical characteristics. By considering all the electrical characteristics, we find that Mo0.9N0.1 (=MoN(2.4)) shows higher work function and better electrical characteristics such as hysteresis, SILC, stress induced charge trapping. Moreover, the differences of MoN metal gate inserting TiN layer in different position were compared. Metal gate with MoN/TiN film exhibits better performance for all the electrical characteristics despite a little lower WF. The results show that MoN/TiN metal gate electrode is better than TiN/MoN metal one and it can be a promising candidate for MOS device applications. Finally, the integration of metal gate and high-k dielectric was investigated. MoN/TiN and HfOxNy were selected as the metal gate and gate dielectric candidates to study the electrical characteristics and thermal stability. The experimental results show that thin EOT and acceptable electrical characteristics are observed in MoN/TiN/HfOxNy MOS device. Furthermore, acceptable thermal stability is also achieved.