Thermal Stability of Aluminum Doped Zinc Oxide Thin FilmsAnalyzed by Thermal Desorption Method

• Main Authors: Sheng-Hua Wu, 吳昇樺
• Other Authors: 張慎周
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/km2ba7

碩士 === 崑山科技大學 === 電機工程研究所 === 97 === For evaluating thermal stability of aluminum doped zinc oxide(AZO)thin films, a series of AZO films with different processing recipe were measured with thermal desorption tool. Relative low thermal desorption and stable electrical, optical and materials properties of AZO films process recipe will be found after analyzing these measured results. The sample holder of thermal desorption tool was linearly heated from room temperature to 500℃ with constant heating rate 10℃per minute. All desorption species show similar desorption peak temperature position around 100℃and 200℃ nearby corresponding to relative maximum desorption rate. The desorption intensity shows increase with temperature up to 200℃. The aluminum species shows maximum thermal desorption amount among all desorption species of AZO thin films, One report describes thermal stability of extrinsic semiconductor is higher than that of intrinsic semiconductor our result is different with that scenario. There are several desorbed species observed from thermal desorption spectroscopy (TDS) by the species to know that The lowest intensity corresponds to best thermal stability condition is the substrate temperature kept at 200℃ under as best thermal stability condition. Because this experiment process is under high vacuum environment, the heating rate for 10℃/Min slow heating rate: For checking the (TDS) measured result accuracy, some of AZO thin films before and after TDS were with energy dispersive spectroscopy (EDS) measurement. The EDS results indicate for AZO films prepared under the same recipe, the aluminum content decrease most among all species for AZO thin films after TDS measurement. This data supports TDS measurement results. The chemical analysis is measured by X-ray photoelectron spectroscopy (XPS). It was found that after thermal desorption, the oxygen vacancy proportion increases, the adsorbed the oxygen in AZO films has the reduction, causes the conductivity promotion, and by electrical, optical and structure analysis after thermal desorption obviously improves. And that after TDS measurement the average optical transmittance reaches 92.38% of AZO thin films, meets condition of the thin film solar cell industry. The AZO thin film with the following hydrogen heat treatment checked by the TDS, The oxygen thermal desorption quantity has reduces. And obtains the electrical resistivity after the hydrogen annealing 300℃ condition 8.32×10-4 (ohm-cm), reduced about 28% compared to before TDS measurement, The electrical resistivity of the AZO films samples that after one month storage does not change for the substrate temperature non-heated. This result contributes thermal stability guide for thin films solar cells industry in producing transparent electrodes.