Direct CoSi_2 thin-film formation with homogeneous nanograin-size distribution by oxide-mediated silicidation

摘要

By annealing at 460℃ for 120 s followed by 600℃ 120 s, nanocrystalline CoSi_2 thin film with an average grain size of 5 nm can be directly formed from a Co/SiO_x/Si multilayer with the SiO_x as a mediated layer. It is found that annealing at 460℃ for enough time is crucial for generating enough diffusion channels within the SiO_x layer. After these channels are created, subsequent annealing at 600℃ keeps these channels open and is responsible for rapid grain growth. In other words, by using two-step annealing, nucleation and growth processes can be effectively controlled and, hence, the resulting microstructure. The homogeneous nanograin-size distribution is important for ultralarge-scale integration technology below 90 nm to prevent resistance degradation induced by CoSi_2 agglomeration.