- 學位論文
ITO薄膜之製備及性質分析
Preparation and Characterization of ITO Thin Films
摘要
ITO導電薄膜為光電產業的關鍵材料之一。本研究採用成本較低且水解性高的金屬鹽類硝酸銦（In(NO3）3•1H2O）與氯化亞錫（SnCl2•2H2O）作為前驅物溶於無水酒精中，製備ITO溶凝膠並且利用浸漬鍍膜的方式將其轉鍍於玻璃基材上，最後於大氣下高溫煅燒形成透明且具導電性之ITO薄膜。為了探討製備條件對ITO薄膜性質的影響，分別改變如下參數:不同錫銦比；不同煅燒溫度；不同煅燒時間；及重複鍍膜。將錫銦比為12之ITO薄膜以四點探針法分析測得最低片電阻值為3.4 × 103 Ω/sq；化學分析能譜儀（ESCA）與X光能量散佈分析儀（EDS）分析化學組態及表面化學成分；再以X光繞射儀（XRD）分析其晶格結構分佈及結晶強度；掃描穿隧式電子顯微鏡（STM）與掃描式電子顯微鏡（SEM）對ITO薄膜作表面微結構的觀測與分析。實驗發現當錫銦比逐漸增加時，電阻值有先降後升的趨勢，並且晶形繞射峰之半高寬亦有先降後升的趨勢，可顯示出晶形結構及強度與電阻值兩者間有密切關係。
並列摘要
Indium-tin-oxide (ITO) thin film is one of the indispensable materials for optical electronics application. In this work, uniform and transparent ITO films were deposited onto glass substrates using a sol-gel method. The initial sols were prepared from anhydrous ethanol solutions of indium nitrate (In(NO3)3.1H2O) and tin chloride dehydrate (SnCl2．2H2O), two potential metal salt precursors for ITO. In order to optimize the preparation conditions for ITO thin film, the following parameters have been changed and studied throughout in this thesis : Sn/In ratio, annealing time, annealing temperature, and number of repeated coating cycles. Depending on compositions, the electrical resistivity of ITO films varied from 47 × 104 to 3.4 × 103 Ω/sq, and the minimum value for the electric resistivity was observed for the films containing 12 % Sn by weight. Increasing heat treatment-temperatures from 350 °C to 600 °C led to increase in conductivity up to one order of magnitude. X-ray diffraction (XRD) was employed for the crystal structure determination, and electron spectroscopy for chemical analysis (ESCA) for chemical state identification. The film resistivity decreases as Sn/In ratio increases, reaching a minimum at 12 % and increases at higher Sn/In value. Similar trend has been found in the ITO grain size as a function of Sn/In ratio. The correlations among the film properties and the film preparation conditions are discussed in this thesis.