A study on the wet etching process of AZO(ZnO:Al)transparent conducting film

• Main Authors: Yu-Tsang Chien, 簡毓蒼
• Other Authors: Yi-Cheng Lin
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/56879243730170013917

碩士 === 國立彰化師範大學 === 機電工程學系 === 94 === The purpose of this study is to investigate the effect of wet etching process on the AZO(ZnO:Al) film. RF magnetron sputtering system was used to deposit AZO thin film on 1737F glass substrates. Sputtering parameters were adjusted and heat treatments were employed to obtain the optimal that yield the suitable optoelectronic properties. In order to understand the effect of etching process on AZO film, the etching process were influenced by etchant temperature and concentration, etchant and photoresist were carried out with TMAH and AZ4620. The etching rate, deposition rate, electivity resistivity, crystalline, surface morphology and root mean square roughness(rms) of the AZO film before/after the etching process were measured by α-step, four point probe, x-ray diffraction(XRD), scanning electron microscopy (SEM) and atomic force microscopy(AFM), respectively. The composition analysis and depth profile of the ZnO:Al2O3 thin film were analyzed by EDS and SIMS. From the result, the optimal conditions to get suitable optoelectronic AZO films are set as : RF power 200 Watt, thickness 200nm, substrate temperature 100℃, work pressure 1.0×10-2 torr and annealing 350℃ 1hour, the lowest resistivity of AZO in this study is 2.38×10-3Ω-cm and the optical transmission is higher than 85%. The optimum etching process parameters is 2.38% TMAH at 45℃, and the average etching rate is 21.82nm/min. The activation energy is increasing with etchant concentration decreased, and etching rate is increasing with etchant temperature and concentration increased. The resistivity increased from 2.38×10-3 to 3.01×10-3 Ω-cm, and the optical transmission decreased from 88.71% to 82.68% due to the chemical stability of transparent conducting AZO film is bad, and light etching from photoresist AZ4620, the surface roughness of AZO film increased from 1.13nm to 3.094nm by etching process. The carbon element of AZ4620 included AZO film by baked process, an orientation of the c-axis representing the peak of the reflection from (002) plane becomes weaker and a slight difference in normalized SIMS Al counts by etching process.