A low-temperature method for improving the performance of sputter-deposited ZnO thin-film transistors with supercritical fluid

Abstract

A low-temperature method, supercritical CO(2) (SCCO(2)) fluid technology, is employed to improve the device properties of ZnO TFT at 150 degrees C. In this work, the undoped ZnO films were deposited by sputter at room temperature and treated by SCCO(2) fluid which is mixed with 5 ml pure H(2)O. After SCCO(2) treatment, the on/off current ratios and threshold voltage of the device were improved significantly. From x-ray photoelectron spectroscopy analyses, the enhancements were attributed to the stronger Zn-O bonds, the hydrogen-related donors, and the reduction in dangling bonds at the grain boundary by OH passivation.