| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 95 === Transparent and conductive oxide (TCO) thin films, which have wide low resistance and high transmittance in the visible wavelength range, have been widely used as various applications. Besides, SnO2 (wide band-gap) has been known to be excellent material for these applications. SnO2 is a n-type semiconductors and has some oxygen vacancies. Other elements will be doped in order to improve electrical property. In this study, SnO2：(Sb, Cu) thin films will be deposited by RF magnetron sputtering using Sb2O3 and CuO co-doped SnO2 ceramic targets. The effects of the RF power, oxygen ratio, targets composition and heat treatment on the electrical and optical properties of SnO2：(Sb, Cu) thin films were investigated.
The experimental results show the addition of Sb2O3 can improve the electrical properties of SnO2 bulks, but suppress bulk density. Therefore, we can obtain targets with highly dense and good electrical property by adding Sb2O3 and CuO. With increasing the contents of Sb¬2O3, the optical and electrical properties of the films degenerate and (2Sb2Cu) films have the best properties. Furthermore, RF power and oxygen ratio parameters have significant influence on the composition, electrical properties and optical properties. Because film crystallization increases, it is helpful to improve film properties. Electrical properties worsen with decreasing oxygen vacancies. On the RF power(120W) and oxygen ratio(0%) parameters, (2Sb2Cu) films have better resistivity 2.5×10-2Ω-cm.
In order to further improve the optical and electrical properties of SnO2：(Sb, Cu) films, the as-deposited films were heat-treated at 250、500°C in O2(oxidation atmosphere) and N2(reduction atmosphere).Under oxidation atmosphere, the resistivity and transmittance of films raise. Under reduction atmosphere, the resistivity of films decrease to 9.1×10-3Ω-cm, but transmittance slightly decrease to 70~75%. Therefore, the purpose of this work is to obtain optical and electrical optimum of SnO2：(Sb, Cu) thin films by controlling sputtering parameters and heat treatment conditions.
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