Frequency Response and Devices Performance of the Indium Zinc Oxide Thin Film Transistors

Abstract

A 1um-gate length field effect thin film transistor was fabricated on a glass using indium zinc oxide (IZO) as the channel layer. The IZO film was deposited by rf magnetron sputtering at room temperature. A thin SiNx film was used as the gate insulator by plasma enhanced chemical vapor deposition. The depletion mode transistor has a threshold voltage -2.5V, maximum transconductance 7.5mS/mm at VDS=3V , and saturation current 2mA/mm at VGS=0V. The field effect mobility is 14.5 cm2.V-1.s-1, and the subthreshold voltage swing is 2.08V/decade. The on/off ratio is >105. The frequency response are measured at VGS=0V and VDS=3V. The cut-off frequency, ft, is 180MHz and the maximum oscillation frequency, fmax, is 155MHz.