Ellipsometric study on residual stress and opto-electrical properties of AZO and ITO thin films

• Main Authors: Chih-kai Hsu, 徐至凱
• Other Authors: Keh-moh Lin
• Format: Others
• Language: zh-TW
• Published: 104
• Online Access: http://ndltd.ncl.edu.tw/handle/94a5pu

碩士 === 南臺科技大學 === 機械工程系 === 103 === With the flourishing development of the opto-electrical industry as well as related research, the demand for TCOs thin film has greatly increased. Among them, the ITO films have a large share on the market. AZO is a non-indium material with great potential. Since the industry requires that TCOs thin films have higher quality and better property, problem of residual stress cannot be ignored. In this study, sputtering method is used to prepare AZO and ITO films of different thicknesses. For AZO/Glass and ITO/Glass, spectroscopic ellipsometer (SE) method is used to understand the residual stress distributions in TCOs films. The results of stress analysis show that before annealing, the AZO thin films suffer planar pressure stress, which reduces as the film thickness increases. After annealing, this stress is released. The changes of residual stress and the film thickness are not obviously relevant. SE analysis shows that: 1. The Lorentz model consists with the rough layer of the AFM measurements. 2. The Lorentz model is more suitable for AZO film with low conductivity. For ITO Films with high conductivity, choosing a proper oscillator model is very important. 3. SE fitting showed that the residual stresses affect the optical properties, particularly when the films are very thin. This knowledge can be used to detect stress changes in the future. The analysis of opto-electrical properties of ITO shows that: 1. High sputtering power and low working pressure can result in high carrier concentration. 2. Low sputtering power and high working pressure result in high carrier mobility. 3. The best sample has a resistance of 2.9×10-4 Ωcm, a carrier mobility of 30 cm2/Vs, and a carrier concentration of 8.6×1020 cm-3.