Numerical modeling of stress build up during nickel silicidation under anisothermal annealing

Reactive diffusion in the Ni/Si system has been studied by annealing nickel thin films deposited on a (1 0 0)silicon crystal. A curvature measurement technique was used to study the stress build up during nickel silicidation. The first silicide to grow is Ni2Si. Its occurrence creates compressive stresses, which relax according to time and temperature of annealing. A new model which takes into account relaxation activated by temperature and thermal expansion of layers during growth is proposed. This approach introduces the material parameters for the viscoplastic constitutive equation and phase change characteristics like activation energy for Ni2Si growth and Ni grain growth. The agreement between experiment and numerical simulation is rather good.