Stress-induced morphology and fine-line stability enhancement of NiSi on poly-SiGe with a buffer polycrystalline silicon interlayer

Abstract

The thermal and morphological stability of NiSi is enhanced by inserting a polycrystalline (poly-Si) buffer layer between the Ni and poly-SiGe films. NiSi films formed on poly-Si/poly-SiGe stack layers possessed continuous, smooth structures after annealing at 500-850 degrees C. Moreover, nickel germanosilicide [Ni(Si, Ge)] lines formed on the poly-SiGe exhibited a fine-line effect, i.e., the sheet resistance increased upon decreasing the linewidth, whereas the sheet resistance of NiSi lines formed on the poly-Si/poly-SiGe stack layers remained less than 5 Omega/square. A model for the stress-confined grain growth and recrystallization is proposed to explain the improved properties of the poly-Si-buffered film. (c) 2008 American Institute of Physics.