Growth temperature influence on nanocrystalline ZnO thin film FET performance

Nanocrystalline ZnO (nc-ZnO) thin film transistors (TFT) are being developed for applications that require much higher performance than TFTs available from other all thin film technologies. Because of their unique closely packed nanocolumnar structures, uniform quality nc-ZnO films can be fabricated over large nonconformal surfaces. Excellent performance characteristics were demonstrated with devices fabricated on GaAs and Si substrates. Devices with 2μm gate lengths had field effect mobilities in excess of 100 cm²/V.s, drain current on/off ratios of better than 10¹², transconductance of 80mS/mm and current densities higher than 400mA/mm. High frequency cut-off frequency values of f_T=2.45GHz and f_max=7.45GHz were demonstrated with 1.2μm gate length devices.