| Summary: | 碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 88 === In the study, TiNi SMA thin films have been prepared by RF sputtering on SiNx-deposited (100) silicon wafer. SiNx was deposited by PECVD. Interfacial reactions between TiNi and SiNx were investigated after different annealing temperatures. After 500℃×30min annealing, TiNi thin films were crystallized, and a layer enriched with Ti and Ni was grown at the interface between TiNi and SiNx. For specimens annealed above 600℃, the B2 and B19’ phases of TiNi were found. That is attributable to the growth of reaction layer as well as the precipitation of Ti2Ni and TiNi3. The precipitation will deteriorate the compositional homogeneity of TiNi thin films and shift the transformation temperature. After sputtering, oxide was observed at the interface between TiNi and SiNx. For the case of annealing below 600℃, the oxide was TiOx, while it becomes Ti4Ni2O when annealing is above 600℃. TiN is readily grown at the interface between TiNi and SiNx, and Si diffusion is hindered by the TiN layer. No crystalline phase was found when annealing is below 600℃, however, after 700℃ annealing, crystalline silicide and oxide can be observed and identified by TEM diffraction. In the study of TiNi/SiNx/Si diffusion couple at 960℃, E phase and V phase are formed at the interface, and the interface growth is controlled by the Si diffusion from the analysis of growth rate of reaction layer. In contrast to the result of TiNi/Si diffusion couple, SiNx plays an critical role as a diffusion barrier.
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