Atomic layer deposition of Nb-doped ZnO for thin film transistors

作者：Shaw A; Wrench J S; Jin J D; Whittles T J; Mitrovic I Z; Raja M; Dhanak V R; Chalker P R; Hall S^*

来源：Applied Physics Letters, 2016, 109(22): 222103.

DOI：10.1063/1.4968194

We present physical and electrical characterization of niobium-doped zinc oxide (NbZnO) for thin film transistor (TFT) applications. The NbZnO films were deposited using atomic layer deposition. X-ray diffraction measurements indicate that the crystallinity of the NbZnO films reduces with an increase in the Nb content and lower deposition temperature. It was confirmed using X-ray photoelectron spectroscopy that Nb5+ is present within the NbZnO matrix. Furthermore, photoluminescence indicates that the band gap of the ZnO increases with a higher Nb content, which is explained by the Burstein-Moss effect. For TFT applications, a growth temperature of 175 degrees C for 3.8% NbZnO provided the best TFT characteristics with a saturation mobility of 7.9 cm(2)/Vs, the current On/Off ratio of 1 x 10(8), and the subthreshold swing of 0.34 V/decade. The transport is seen to follow a multiple-trap and release mechanism at lower gate voltages and percolation thereafter. Published by AIP Publishing.

• 出版日期2016-11-28