Due to the aggressive scaling of CMOS devices, it is necessary to provide a metal gate solution to replace the conventional process known as a self-aligned poly-silicon gate. Molybdenum (Mo) possesses several properties that make it attractive as a CMOS gate electrode material. In addition, Mo has been identified as a candidate for “single-metal / dual workfunction” technology, with the ability to tune the workfunction by the introduction of nitrogen. In this study, the correlation between workfunction of the Mo gate and the incorporation of nitrogen was investigated. The flat-band voltage shift was extracted from the obtained C-V Characteristic curves. Both reactive sputtering and ion implantation methods provided a negative shift in the C-V characteristics. The observed shift was greater for the ion implantation methods. These results indicate that a Mo-gate process with incorporation of nitrogen is a good candidate for replacing the self-aligned poly-silicon gate process.
"Workfunction Tuning of Molybdenum Gate by Nitrogen Incorporation (May 2006),"
Journal of the Microelectronic Engineering Conference: Vol. 16
, Article 7.
Available at: http://scholarworks.rit.edu/ritamec/vol16/iss1/7