Effects of thermal processes after silicidation on the performance of TiSi/sub 2//polysilicon gate device

The effects of thermal processes after silicidation on the gate depletion, threshold voltage (V/sub th/) shift, drive current, and sheet resistance of TiSi/sub 2//polysilicon (Ti-polycide) gate devices are evaluated. The dopant depletion of the polysilicon film, which is known to increase the V/sub th/ and to degrade the drive-current, increases with increasing temperature of the post-thermal process. However, the V/sub th/ roll-off characteristic in nMOSFETs is enhanced with increasing temperature. Furthermore, the drive-current is significantly degraded by the gate reoxidation process. The sheet resistance of the Ti-polycide gate increases with gate reoxidation as well as with increased post-thermal processes.