| Summary: | 碩士 === 國立清華大學 === 材料科學工程學系 === 92 === In this work, Zr17Ta16Ti19Nb22Si26 amorphous thin films have been prepared from high entropy alloy target of the same composition. The derived films were subsequently annealed at various temperatures from 473 K to 1173 K for 10 minutes. X-ray diffraction results indicated that the films remained in amorphous form. Nevertheless, the amorphous scattering peak became more diffuse as the annealing temperature increased, suggesting the increase of degree of disorder with the annealing temperature. In addition, resistivity and hardness of films were also found to increase with annealing temperature. From the reduced density function, the metal-Si bonding was found to change gradually in the annealing process. In the as-deposited film, Si atoms stayed as solutes in the alloy matrix, whereas metal-Si bonding was more silicide like in the film subjected to 1173 K-anneal. The gradual formation of silicide-like bonding might cause the atomic spacing to split into two distinct lengths, lower the free electron density, enhance the electronic scattering, and bonding strength of amorphous films. This explained the more diffuse scattering peaks of XRD, and the increase of resistivity and hardness of post-annealed films.
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