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

Abstract

The issue of agglomeration and layer inversion has remained critical because conductivity of thin silicide 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 5 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).