STRESSES AND MORPHOLOGICAL INSTABILITIES IN SILICIDE POLYCRYSTALLINE SI LAYERED STRUCTURES

The evolution of stress in silicide/polycrystalline Si (poly-Si) layer ed structures has been monitored in situ in the temperature range of 2 5-700-degrees-C. At elevated temperatures, the silicide/poly-Si struct ure becomes morphologically unstable. The grain growth of poly-Si lead s to an inversion of the positions of the two layers. The in situ stre ss measurement shows that this structural degradation is accompanied b y a substantial increase in tensile stress of around 0.4 GPa, for NiSi , Pd2Si, and PtSi. A simple calculation indicates that the magnitude o f the stress increase can be accounted for, at least to a large extend , by the volume contraction caused by the grain growth of poly-Si.