On the morphological changes of Ni- and Ni(Pt)-silicides

The issue of agglomeration and layer inversion has remained critical because conductivity of thin suicide films is sensitive to the degradation of the film morphology. The purpose of this work is to study the morphology degradation that includes agglomeration and layer inversion of NiSi and Ni(Pt)Si. Agglomeration was observed to be preceded by holes evolution. It was found that the addition of Pt has led to improvement in the agglomeration behavior of NiSi but have little influence on the layer inversion when the amount of Pt is S atom % in Ni(Pt) on the undoped poly-Si. Increasing the Pt concentration to about 10% shows improvement in the layer inversion behavior compared to 5% Pt. The agglomeration behavior and layer inversion with the addition of the Pt are discussed in terms of the controlling factors of grain boundary energy, interface energies, and nature of the silicide formed. The improved agglomeration associated with Pt addition is attributed to a lower interfacial energy leading to lower grain boundary mobility and reduced driving force for hole evolutions. In addition, suppression of layer inversion can be attained by silicidation with the use of thin Ni(Pt) (∼ 10 nm).