| Summary: | 碩士 === 國立清華大學 === 工程與系統科學系 === 98 === The objective of this study is to understand the difference of the behaviors of ZrN thin film oxidation in different atmospheres. The annealing atmosphere and temperature were chosen to be the designate variables. In this study, ZrN thin film was deposited on Si substrate, and the samples were annealed in vacuum and flowing nitrogen respectively at four different temperatures for one hour. The oxygen partial pressure was monitored by a zirconia oxygen sensor during annealing. The solubility of oxygen in ZrN was calculated by comparing the difference of measured oxygen partial pressure between annealing with and without specimen. The dissolution of oxygen in ZrN is an exothermic reaction. The oxidation behavior was examined from thermodynamic and kinetic perspectives. Results indicated that the composition, structure and properties of the specimens annealed in vacuum and flowing nitrogen were completely different. All ZrN thin films were oxidized under annealing in flowing nitrogen. On the other hand, the specimens in vacuum annealing revealed substantial formation of ZrO2 at 1000°C and above. For vacuum annealing, it is observed that the oxygen partial pressure in the system, ranging from 10-15 to 10-8 atm, significantly varied with temperature from 800 to 1100 °C, which is the main factor leading to oxidation. The surface oxide layer formed in vacuum annealing may be different from that in nitrogen gas, and thereby affecting oxidation behavior. Blisters were observed on the surface for the samples annealed in nitrogen. Once the blisters formed, more oxygen could penetrate the thin film through the cracked blisters and the ZrN film would be oxidized rapidly. To avoid blister formation and maintain a smoother surface, heat treatment of ZrN in vacuum was a feasible method.
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