Study of Ti addition in channel layers for In-Zn-O thin film transistors

Ti added In-Zn-O thin films and their application to thin film transistors were studied. The In-Zn-O films were deposited by pulsed plasma deposition using targets with various Ti contents added. High content of Ti in In-Zn-O films was found to induce a decrease in carrier concentration. The effect was attributed to suppression of oxygen vacancies by Ti incorporation. For thin film transistors with Ti added In-Zn-O as channel layer materials, threshold voltage showed positive shift as Ti content increases and field effect mobility was not decreased at the same time. Results of a bias stress experiment on device fabricated at room temperature are also given.