Effects of the channel thickness on the structural and electrical characteristics of room-temperature fabricated ZnO thin-film transistors

We report the fabrication and characteristics of ZnO thin-film transistors (TFTs) having different channel thicknesses. The ZnO films were deposited as active channel layers on SiO2/p-Si substrates by rf magnetron sputtering at room temperature. Effects of the channel thickness on the structural and electrical properties of ZnO TFTs using a bottom-gate configuration were investigated. The crystalline quality and channel conductance of the ZnO films were enhanced as the channel thickness increased. The ZnO TFT with the optimized channel thickness exhibited enhancement mode characteristics with the threshold voltage of 9.9 V, the on-to-off current ratio of ~105 and the field-effect mobility of 0.1 cm2 V−1 s−1. This research implies that ZnO TFTs produced by a simple and low-cost technique could be applicable to electronic devices.

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