Application of electrodes on high mobility oxide thin film transistors for high resolution displays and photo sensors

Abstract

Oxide thin-film transistors (TFTs) have been actively studied to realize displays capable of delivering clearer and higher-quality image information. In this study, the high-mobility oxide thin-film transistors (TFTs) were studied to realize high-resolution displays. Especially, the effect of the source/drain electrodes on the channel-shortening effect was analyzed, which is a problem that occurs as the channel length decreases. The origin of the difference in the channel-shortening effect depending on the Cu diffusion barrier electrodes was identified, and the channel-shortening effect was suppressed by applying appropriate Cu diffusion barrier materials. TFTs with excellent characteristics even at the short channel lengths was fabricated with stably driving under annealing conditions. In addition, a phototransistors having increased absorption for the visible light was demonstrated by engineering energy states in the channel layer through hydrogen diffusion from source/drain region into the channel layer. The fabricated device exhibited increased photoresponse in visible-light and improved negative bias illumination stress (NBIS) stabilities. Furthermore, the phototransistors demonstrated in this study have an advantage of being compatible with existing processes and an easy fabrication method because it is implemented by applying the Cu diffusion barrier materials deposited on the source/drain region.