| Summary: | 碩士 === 國立虎尾科技大學 === 光電與材料科技研究所 === 93 === In this study , we depoisited a 10 nm TaC thin film and a 100 nm copper thin film in order at （100）oriented p-type silicon substrate by a rf / dc-magnetron system. And to investigate the processes of the sputtered TaC thin film and to study diffusion barrier behaviors of TaC . The effects of TaC thin films on the high temperature diffusion behaviors between copper and silicon were examined by resistance measurement, x-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM).
It shows that the as-deposited TaC is a FCC structure, with a resistivity of 251 ??-cm. The results of the relative changes in sheet resistance (?R/Ro) for 100nm Cu/10nm Ta/Si stacked samples as a function of annealing temperature shows that ?R/Ro increases slowly at a low annealing temperature and then increases drastically at a specified heightened temperature. It increases slightly at temperatures below 600 oC, and rises abruptly when the temperature exceeds 650 oC. The sheet resistance results consist with the examinations of XRD and SEM, Moreover, The TaC barrier can effective hinder Cu diffusion to si at 550 ℃ and the failure temperature of TaC barrier is about 600℃.TEM observations clarify that the failure mechanism is the local defects of TaC barrier films induced by high temperature annealing, consequentially, Cu atoms diffuse through the local defects of TaC, then copper silisides are formed
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