| Summary: | 碩士 === 國立清華大學 === 工程與系統科學系 === 94 === Nanocrystalline Zr(N,O) thin films were deposited on p-type (111) Si wafers using hollow cathode discharge ion-plating (HCD-IP) system. The effect of oxygen flow rate (ranging from 0 to 8 sccm) on the composition, structure and properties of the Zr(N,O) thin films was investigated. The oxygen content of the thin film determined using X-ray Photoelectron Spectroscopy (XPS) increased significantly with the increase of the oxygen flow rate. As the oxygen content increased, the color of Zr(N,O) thin film changed from golden yellow to blue and then slate blue; the microstructure observed by Field-Emission Gun Scanning Electron Microscopy (FEG-SEM) changed obviously. Phase separation was observed in X-ray Diffraction (XRD) patterns when the oxygen content was higher than 9.7 at%. Glancing incidence X-ray diffraction (GIXRD) results also indicated that phase separation of ZrN and monoclinic ZrO2 occurred. The grain sizes of the ZrN and ZrO2 phases in the Zr(N,O) films were ranged from 12 to 5 nm and 8 to 2 nm, respectively. A phase separation mechanism was proposed: the ZrO2 phase precipitated on grain boundaries as the oxygen content was lower than 32 %, and above which, a growth competition between ZrN and ZrO2 occurred. The hardness of the film increased slightly as the oxygen content was less than 9.7 % and decreased to 15.7 GPa, a typical value of ZrO2 phase, as the oxygen content further increased. The total residual stress of the film was measured using an optical method and the residual stresses of ZrN and ZrO2 phase were measured separately using modified XRD sin2Ψ method. The total stress was close to that in ZrN phase as the fraction of ZrO2 phase was less than 30 %, and was close to that in ZrO2 phase as the fraction was over 30 %. The electrical resistivity of the film increased significantly with the increase of oxygen content. Phase separation showed consistent effects on film properties. As the fraction of ZrO2 phase was small, the properties were more close to those in ZrN. When ZrO2 fraction was about 30 %, the properties of ZrO2 would dominate the film properties.
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