Effect of N[sub 2]O Plasma Treatment on the Performance of ZnO TFTs

Postfabrication rapid thermal annealing (RTA) and subsequent nitrous oxide plasma treatment improved the performance of zinc oxide (ZnO) thin-film transistors (TFTs) in terms of off current and on/off current ratio by almost 2 orders of magnitude. The off current of and on/off current ratio of obtained after RTA were improved to and , respectively, by the subsequent plasma treatment. X-ray photoelectron spectroscopy analysis of the TFT samples showed that the RTA-treated ZnO surface had more oxygen vacancies as compared to as-deposited samples, and the oxygen vacancies at the surface of RTA-treated ZnO were reduced by subsequent plasma treatment. The reduction of oxygen vacancies at the top region of the ZnO channel is the cause of better off current and on/off current ratio of the TFTs.