Kwan-Jong Roh

Thermally robust Ta-doped Ni SALICIDE process promising for sub-50 nm CMOSFETs

For sub-50 nm device application, Self-Aligned siLICIDE (SALICIDE) process by NiTa alloy has been developed for the first time. Use of NiTa-alloy makes nickel silicide on 50 nm gate thermally-robust up to 600/spl deg/C during device fabrication. NiTa SALICIDE process can also achieve excellent value and distribution of sheet resistance on 30 nm gate as well as low junction leakage current compared to Co SALICIDE. Furthermore, the drive current of PMOS is greatly increased. As a result, high-performance 90 nm MOSFETs is successfully integrated with NiTa SALICIDE process.

Effect of a noble annealing system on nickel silicide formation

We have investigated the formation of NiSi dependence on three types of annealing systems: annealing systems-I, -II, and -III. The annealing system-I transfers heat by radiation from tungsten halogen lamps in a N2 atmosphere to the wafer and the annealing system-II by conduction from a heated hot plate in vacuum to the wafer. On the other hand, annealing system-III uses a combination of convective and gas phase conductive heat transfer in a N2 atmosphere for wafer heating. Smooth surface and interface morphologies and good electrical properties were obtained for NiSi layers formed using annealing system-III. The wafer heat transfer mechanism from the heat source to wafer is shown to influence the morphological and electrical properties of NiSi