Probing Ge Segregation in NiSi_(1-U)Ge_u Using Micro-Raman Spectroscopy

摘要

The solid-state reaction of Ni on strained and relaxed (001) Si_(0.8)Ge_(0.2) has been studied by micro-Raman scattering with a particular emphasis on the influence of Ge-rich Si_(1-z)Ge_z segregation in NiSi_(1-u)Ge_u films. Raman scattering is found to be a sensitive and useful tool to probe such Ge-rich Si_(1-z)Ge_z segregation that takes place preferentially at the germanosilicide/Si_(1-u)Ge_u interface. From Raman measurements, the composition of Ge within Ge-rich Si_(1-z)Ge_z grains formed due to prolonged rapid thermal annealing can be mapped and the results show consistency with transmission electron microscopy. We have also observed that both shorter annealing time and addition of Pt can effectively suppress the Ge segregation at the interface. Furthermore, Raman scattering can clearly detect the onset temperature of Ge segregation for different thermal annealing conditions.