| Summary: | 碩士 === 義守大學 === 材料科學與工程學系 === 89 === Tantalum-Nitride (Ta-N) thin films were sputtered onto the (100) crystal plane of P-type silicon substrates. The Ta/N ratios of the films were controlled by a optical emission spectrometry (OES). Phase transformations, microstructures, variation of electrical properties of the Ta-N films before and after heat-treatments were investigated.
Thickness of Ta-N films increased with decreasing the OES% values between 100% and 70%. Due to target poisoned, the thickness of films were about 5000 ~ 6000Å when OES% was lowered than 70%. At OES 100%,Ta-N film showed -Ta structure. Amorphous Ta-N film with Ta2N composition was observed from the film deposited at OES between 45% and 58%. Before annealing, resistivity and temperature coefficient of resistor (TCR) of the films increased with decreasing OES% value. Consistent resistances and TCRs were obtained from the films deposited at condition of OES 70% ~ 60%.
After heating-treatment, the films deposited at OES 100%,OES 63%,and OES 48% had crystal structure as -Ta,Ta2N,TaN respectively. When Ta-N films were heat-treated at temperature between 200oC ~ 600oC, the resistivities of the films increased with increasing heat-treatment temperature. Crystallization of the film became evident and the resistance decreased, when it was annealed at temperature higher than 600oC. Interactions between TaN films and Si Substrates were observed from 600oC heat-treated samples. Temperature Coefficient of resistor also decreased with increasing heat-treatment temperature. Ta-N films had the lowest TCR when they were annealed at temperature between 400oC and 600oC.Ta-N films deposited at OES 63% and annealed at 400oC for 90min had Ta2N structure, they had resistivities of 489.45-cm and TCR of 20.43 ppm/oC.
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