Bootstrapped ring oscillator with propagation delay time below 1.0 nsec/stage by standard 0.5µm bottom-gate amorphous Ga2O3-In2O3-ZnO TFT technology

This paper describes the design and fabrication of the high performance ring oscillator with the standard 0.5 mum bottom-gate amorphous Ga₂O₃-In₂O₃-ZnO TFT technology. A series of process and geometry parameters of devices are sophistically optimized to decrease the circuit signal´s propagation delay and, in particular, a novel 3 TFTs bootstrapped inverter structure using the load-transistor´s overlap capacitance as the bootstrapped capacitor is applied. Finally, the propagation delay time of 0.94 ns/stage for a supply voltage of 9 V is achieved in the 5-stage ring oscillator, which is over 75 times faster than previous report.