​Wavy Channel TFT Based Digital Circuits
A. Hanna, A. Hussain, H. Omran, S. Alsharif, K. Salama, and M. M. Hussain

We report a Wavy Channel (WC) architecture thin film transistor (TFT) based digital circuitry using ZnO as a channel material. The novel architecture allows for extending device width by integrating vertical fin-like substrate corrugations giving rise to 50% larger device width, without occupying extra chip area. The enhancement in the output drive current is 100%, when compared to conventional planar architecture for devices occupying the same chip area. The current increase is attributed to both the extra device width and 50% enhancement in field effect mobility due to electrostatic gating effects. Fabricated inverters show that WC inverters can achieve 2× the peak-to-peak output voltage for the same input when compared to planar devices. Also, WC inverters show 30% faster rise and fall times, and can operate up to ~2× frequency of the planar inverters for the same peak-to-peak output voltage. WC NOR circuits have shown 70% higher peak-to-peak output voltage, over their planar counterparts, and WC pass transistor logic multiplexer circuit has shown more than 5× faster high-to-low propagation delay compared to its planar counterpart at a similar peak-to-peak output voltage.