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

We present physical and electrical characterization of niobium-doped zinc oxide (NbZnO) forthin film transistor(TFT) applications. The NbZnO films weredeposited usingatomic layer deposition.X-ray diffraction measurements indicate that the crystallinity of the NbZnO films reduces with an increase in theNb content and lowerdeposition temperature. It was confirmed usingX-ray photoelectron spectroscopy thatNb5+ is present within the NbZnO matrix. Furthermore, photoluminescence indicates that the band gap of theZnO increases with a higherNb content, which is explained by the Burstein-Moss effect. ForTFT applications, a growth temperature of 175  °C for 3.8% NbZnO provided the bestTFT characteristics with a saturation mobility of 7.9  cm2/Vs, the current On/Off ratio of 1  × 108, 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.

Source: Applied Physics Letters - November 29, 2016 Category: Physics Authors: A. Shaw, J. S. Wrench, J. D. Jin, T. J. Whittles, I. Z. Mitrovic, M. Raja, V. R. Dhanak, P. R. Chalker and S. Hall Source Type: research