P型透明導電氧化物薄膜製備及 其電性與光學特性之探討

Abstract

自然界中，玻璃是透明物質的代表，金屬則是導電物質的代表。因此兼具透明與導電兩種特性的材料，將可當作所謂的「透明電極」，廣泛地應用至半導體光電產業。例如：平面顯示器、薄膜太陽電池、透明觸控面板及發光二極體等產業。本研究利用自製銅鋁氧化物陶瓷靶及射頻磁控濺鍍法，於製程中改變各種製成參數，試圖沉積具有良好光電特性的CuAlO2薄膜於玻璃基板上。本研究以傳統陶瓷製程，藉著了解不同製程參數對陶瓷塊材之燒結性質變化的影響，製作尺寸精確的靶材。實驗結果顯示，以升溫速率2℃/min於1100℃持溫24小時燒結，可得到膨脹率約10%之2吋銅鋁氧CuAlO2陶瓷靶材。將自製靶材搭載自行組裝之射頻磁控濺鍍系統，在固定基板靶材間距7cm，腔體壓力2×10-3torr、沉積時間3小時下，探討射頻功率(W)、基板偏壓(V)及氧氣通量(S)等電漿製程對薄膜性質的影響。所有磁控濺鍍CuAlO2薄膜試片經X光繞射實驗證實為非晶結構。接著藉由添加參雜物鈣(Ca)10%原子比例改變靶材成分以改善薄膜特性。本實驗其最佳條件為鈣(Ca)10%原子比例摻雜，射頻功率120W，基板偏壓0V，氧氣通量10sccm，所得膜厚157nm，電阻率ρ=60.37Ωcm且在可見光範圍有60%的穿透率。

In nature, glass is the representative of the transparent substance; metal is the typical conducting material. Therefore, a matter exhibits both transparent and good electrical conducting properties is what so called “transparent electrode”. Transparent conducting oxide is extensively applied to the semiconductor and photovoltaic industry, such as flat-panel displays, thin film solar cells, touch panels, and light-emitting diode. We tested several kinds of process parameters to obtain good quality CuAlO2 thin films using custom-made CuAlO2 ceramic targets and RF sputtering method. Under a fixed target-to-substrate distance (7cm), influence of several kinds of parameters on electrical and optical properties, such as the RF power (P), DC bais (V) of the substrate, O2 flow (S) were investigated. All magnetron sputtering-deposited CuAlO2 in this study exhibits amorphous structure. We improved the conductivity of the films by additional doping (Ca).Best film was obtained using the following fabrication process parameters: 10 at% Ca doping target ,RF power of 120W, no DC bias, and oxygen ratio [O2/(O2+Ar2)] of 1/3. Out best achieved resistivity is 60.39 Ohm-cm; and the best averaged transmittance is about 60% within the wavelength range of visible light for film of 157 nm thickness.