Deposition of c-Axis Aligned Crystalline InGaZnO by Mist Atmospheric Pressure Chemical Vapor Deposition for Thin-Film Transistor Applications

This study uses mist atmospheric pressure chemical vapor deposition with deposition/annealing cyclic method to grow ${c}$ -axis aligned crystalline (CAAC) InGaZnO. The material characteristics of the CAAC-InGaZnO are analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence, and an ellipsometer to determine the crystal structure, oxygen deficiency, trap energy level, and energy bandgap. The CAAC-InGaZnO thin-film transistor (TFT) shows better electrical performance than the one based on amorphous InGaZnO, including higher field-effect mobility (90.4 cm $^{2}\,\,\text{V}^{-1}\,\,\text{s}^{-1}$ ), lower OFF-state leakage current (16 pA), steeper subthreshold swing (86 mV/dec), and higher on/off current ratio (>1010). Moreover, the negative bias illumination stress (NBIS) test is used to estimate the stability of the TFT. The threshold voltage of the present CAAC-InGaZnO TFT changes −0.4 V when the TFT is stressed for 10 000 s.