Dual gate indium-gallium-zinc-oxide thin film transistor with an unisolated floating metal gate for threshold voltage modulation and mobility enhancement

In this study, we propose a floating dual gate (FDG) indium-gallium-zinc-oxide (IGZO) thin film transistor (TFT) with a floating metal back gate that is directly contact with IGZO without a dielectric layer. The floating back gate effect is investigated by changing the work function (phi) of the back gate. The FDG IGZO TFT exhibits an improved field-effect mobility (mu), unchanged subthreshold swing (SS), high on/off current ratio, and a tunable threshold voltage ranged (V(th)) from -5.0 to + 7.9 V without an additional back gate power supply. (C) 2011 American Institute of Physics. [doi:10.1063/1.3578403]