氧化銦系列透明導電膜擁有良好導電性及可見光區的高穿透率，廣泛被應用於太陽能電池、觸控式面板及發光二極體等元件上。射頻磁控濺鍍法(RF magnetron sputtering)為目前製備透明導電膜常見方法之一，相較於其他製備方式其擁有沉積快速、低溫及薄膜均勻等特點。本研究利用射頻磁控濺鍍法製備氧化銦錫(ITO)、氧化銦鈦(ITiO)及氧化銦鉬(IMO)三種透明導電膜，並研究調變氬氣流量、射頻功率、製程壓力、氧氣流量與退火溫度等參數對透明導電膜的影響，目標為製備出低片電阻( < 50 Ohm/square)、高載子遷移率( > 40 cm2/Vs)以及在可見光到近紅外光區有高穿透率( > 90 %)的透明導電抗反射膜( 75~80 nm)，能應用於矽晶異質接面太陽能電池，以能夠降低電池的串聯電阻以及提高光穿透率，增加電池轉換效率。
研究結果顯示，氧化銦錫展現出低片電阻(30~100 Ohm/square)、高載子遷移率(40~45 cm2/Vs)以及可見光區高穿透率(86~92 %)的特性，氧化銦鉬則可擁有高載子濃度(2E20~4E20 cm-3)，而氧化銦鈦在光電性質表現上較為一般。調變氬氣流量與提高射頻功率對透明導電膜的光電性質有顯著的影響，在氬氣流量為60~80 sccm以及射頻功率為250 W的製程條下，氧化銦錫、氧化銦鈦與氧化銦鉬達到最低片電阻分別為70 (Ohm/square)、171 (Ohm/square)與104 (Ohm/square)；調變氧氣流量能控制透明導電膜的氧空缺數量，不過對其光電性質影響較不顯著；提高製程壓力會降低靶離子動能，影響薄膜結構且明顯劣化薄膜品質；後退火處理可使原為非晶結構的透明導電膜轉變為多晶結構並降低能帶邊緣缺陷，尤其氧化銦錫在後退火處理後載子濃度得到大幅度的提升使片電阻下降，且可見光區的穿透率從87.3 %提升至92.4 %，本研究在氬氣流量為80 sccm、射頻功率為200 W及退火溫度為500 ℃的製程條件下，可製備片電阻為33 (Ohm/square)及在光波長400 nm-1200 nm的平均穿透率為92.4 %的氧化銦錫(ITO)薄膜。

Indium-based transparent conductive oxide films are widely used in solar cell, touch panel, LED, and other diode elements with superior conductivity and high optical transmittance in visible region. Nowadays, radio-frequency (RF) magnetron sputtering is one common method for preparing a transparent conductive oxide films. Furthermore, compared with other methods, RF magnetron sputtering has several advantages, such as the excellent deposition rates, low temperature, and film uniformity. The indium tin oxide (ITO) thin films, the titanium-doped indium oxide (ITiO) thin films, and the indium molybdenum oxide (IMO) thin films were fabricated by RF magnetron sputtering process. In this study, we modulated the argon flow rate, radio-frequency power, process pressure, oxygen flow rate, and post-annealing temperature to investigate the thin films quality. The target to fabricate the transparent conductive oxide anti-reflection film (75~80 nm) with low sheet resistance ( < 50 Ohm/square), high mobility ( > 40 cm2/Vs), and high transmittance in visible region and near-infrared region that will be applied to amorphous silicon / crystalline silicon heterojunction solar cells. The conversion efficiency of solar cells can be improved by the reduction of series resistance and improvement of light transmittance.
The results of experiments show that indium tin oxide has low sheet resistance (30~100 Ohm/square), high mobility (40~45 cm2/Vs), and high transmittance in visible region (86~92 %). Indium molybdenum oxide has high carrier concentration (2E20~4E20 cm-3). Titanium-doped indium oxide has general optical and electrical properties. It has significant influence on transparent conductive oxide films quality by modulating the argon gas flow rate and increasing the radio-frequency power. Under the condition of argon gas flow rate = 60~80 sccm and radio-frequency power = 250 W, the indium tin oxide, the titanium-doped indium oxide, and the indium molybdenum oxide have the lowest sheet resistance of 70 (Ohm/square), 171 (Ohm/square), and 104 (Ohm/square), respectively. Modulation of oxygen gas flow rate can control the number of oxygen vacancies in films, but it is not obvious to affect the optical and electrical properties of films. In addition, increase process pressure will reduce the kinetic energy of the ions and affect films structure, resulting in deterioration of films quality. Furthermore, post-annealing process can make transparent conductive oxide films transform to crystal structure from amorphous structure, and reduce band edge defects. In particular, post-annealing process can greatly improve carrier concentration and reduce sheet resistance of the indium tin oxide thin films. The post-annealing process can also improve the indium tin oxide thin films transmittance from 87.3 % to 92.4 %. Under the condition of argon flow rate = 80 sccm, radio-frequency power = 200 W, and annealing temperature = 500 ℃, we obtained the low sheet resistance 33 (Ohm/square) and high optical transmittance 92.4 % at 400 nm~1200 nm wavelength of the tin oxide thin film, respectively.

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