Nanocrystalline ZnO films prepared by Pulsed Laser Deposition were used to fabricate the first thin film transistors that
operate at microwave frequencies. Unlike more conventional amorphous Si and organic thin film transistors, which are
only suitable for low speed applications, ZnO-based thin film transistors exhibit figure-of-merit device numbers that are
comparable to single crystal transistors. These include on/off ratio of 1012, current density of >400mA/mm and field
effect mobility of 110 cm2/V.s. Parameters, including film growth temperature, gate insulators, and device layout
designs were examined in detail to maximize performance. We have achieved current gain cut-off frequency, fT, and
power gain cut-off frequency, fmax, values of 2.9GHz and 10GHz, respectively with 1.2μm gate length devices
demonstrating that ZnO-based TFTs are suitable for microwave applications.