Low-temperature processed and self-aligned InGaZnO thin-film transistor with an organic gate insulator for flexible devices

High performance, top-gate and self-aligned In-Ga-Zn-O thin-film transistor (IGZO TFT) was demonstrated at a maximum process temperature of 150 degrees C using a coatable organic gate insulator (OGI). To achieve damage-and contamination-free interface between the IGZO channel and OGI, an organic protection layer (OPL) was proposed. We achieved good TFT properties, such as field effect mobility of 10.2 cm(2)/Vs, subthreshold swing of 0.19 V/dec., and hysteresis of 0.2 V, with minimizing an overlap capacitance between S/D and gate electrodes. Although the TFT showed an abnormal Vth shift under a positive gate bias stress in an ambient air, it could be suppressed by forming an additional organic passivation layer on the TFTs.