Stability Improvement of Nickel Silicide with Co Interlayer on Si, Polysilicon and SiGe

摘要

Thermal stability of nickel silicide is improved by adding a thin Co interlayer at Ni/Si interface. After high temperature anneal, the low sheet resistance of silicide and the low junction leakage of the ultra-shallow junction show the lack of film degradation. The transformation to disilicide phase occurred at a lower temperature. At 850℃, interface shows the truncated facet structure extended 100A to 200A below silicide/Si interface. With Co addition, nickel silicide formed on polysilicon and on SiGe films also show improved thermal stability and low sheet resistance. Formation temperature of disilicide phase occurred at lower temperature in all these cases.