Fast ZnO Thin-Film Transistor Circuits

We report here five-stage ring-oscillator-integrated circuits fabricated using ZnO TFTs with signal propagation delays as low as 100 ns (>1 MHz oscillation frequency) for a 45 V supply voltage. These circuits also operate at a supply voltage as low as 10 V. To our knowledge, these are the fastest ZnO integrated circuits reported to date. We also designed ring oscillators with different source/gate and drain/gate overlap to investigate aspects of the circuit speed.