Mechanisms of ZnO buffer layer in bottom gate ZnO:Al transparent thin film transistors

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• 作者：Yung-Hao Lin^a ; Hsin-Ying Lee^b ; Ching-Ting Lee^a ; ^{ctlee@ee.ncku.edu.tw} ; Cheng-Hsu Chou^c
• 关键词：Al-doped ZnO channel layer ; Magnetron cosputter system ; Transparent thin film transistors ; ZnO buffer layer
• 刊名：Materials Chemistry and Physics
• 出版年：2012
• 期刊代码：58_02540584
• 类别：ms
• 出版时间：15 June, 2012
• 卷：134
• 期：2-3
• 页码：1203-1207
• 文件大小：1212 K

摘要

The structure of Al-doped ZnO (ZnO:Al) transparent thin-film transistors (TTFTs) were deposited at room temperature using a radio frequency magnetron cosputter system. The performances of the ZnO:Al TTFTs were improved by inserting a ZnO buffer layer between the ZnO:Al channel layer and the SiO₂ gate insulator. The ZnO:Al TTFTs with 80-nm-thick ZnO buffer layer exhibited a higher field-effect mobility of 90.1聽cm²聽(V聽s)^鈭?, a lower subthreshold slope of 0.24聽V/decade and a lower maximum surface state density of 2.69聽脳聽10¹¹聽eV^鈭?聽cm^鈭?. The associated on-to-off current ratio of the TTFTs was 1.2聽脳聽10⁸. The performance improvement of the ZnO:Al TTFTs was attributed to crystalline improvement and the releasing functions of lattice mismatching and strain between the ZnO:Al channel layer and the SiO₂ insulator layer.