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

作者：Lin Yung Hao; Lee Hsin Ying; Lee Ching Ting^*; Chou Cheng Hsu

来源：Materials Chemistry and Physics, 2012, 134(2-3): 1203-1207.

DOI：10.1016/j.matchemphys.2012.04.023

• Al-doped ZnO channel layer
• Magnetron cosputter system
• Transparent thin film transistors
• ZnO buffer layer

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 cm(2) (V s)(-1), a lower subthreshold slope of 0.24 V/decade and a lower maximum surface state density of 2.69 x 10(11) eV(-1) cm(-2). The associated on-to-off current ratio of the TTFTs was 1.2 x 10(8). 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.

• 出版日期2012-6-15