In situ resistivity measurement of cobalt silicide formation

In situ resistivity measurements have been utilized to study the reaction and silicide formation between cobalt and amorphous silicon thin films from room temperature to 800 °C. In conjunction, structure and composition changes were analyzed by x-ray diffraction and Rutherford backscattering spectrometry. Formation of Co₂Si, CoSi, and CoSi₂ were observed. Interfacial reaction to form Co₂Si occurs at approximately 400 °C. In bilayers of excess silicon, CoSi forms at approximately 520 °C and, if free silicon is still present, CoSi₂ forms at about 550 °C. In the case of excess cobalt, Co₂Si forms first and is followed by a cobalt-rich solid solution. Co₃Si silicide was not observed.