X-ray photoelectron study of annealed Co thin film on Si surface

The X-ray photoelectron spectroscopy (XPS) study on as deposited as well as 500 °C annealed Co (400 Å)/Si thin film synthesized by electron beam evaporation technique under UHV conditions is reported here. The XPS measurements carried out on as deposited sample rule out the possibility of any phase formation at room temperature. Whereas in 500 °C annealed sample the Co-2p_3/2 peak is observed at ∼778.6 eV binding energy position, where the peak expected due to CoSi₂ resides. The Auger parameters were also calculated at each step of experiment because Auger parameter is always very sensitive to changes in the chemical state of the material. The recorded spectrum on annealed sample shows Auger parameter value of ∼1551.4 eV, which is different from that observed in the as deposited sample (∼1552.1 eV). The obtained results are analyzed and interpreted in terms of CoSi₂ phase formation at the interface with annealing.