Unipolar Schmitt Trigger Based on Antiferroelectric Thin Film Transistor

For the first time, this letter proposes a unipolar Schmitt trigger with two transistors structure composed of an antiferroelectric thin film transistor (AFeTFT) and a feedback thin film transistor (TFT), greatly saving hardware overhead. Due to the antiferroelectricity and positive feedback in circuit, it features unipolar threshold characteristics, achieving a lower threshold voltage of 0.4 V and an upper threshold voltage of 1.5 V, which is crucial for chips powered by single-supply voltage. The experiments demonstrate that reducing the area ratio between the channel and capacitor in the AFeTFT facilitates a positive shift in the lower threshold of Schmitt trigger. Additionally, simulations indicate that as the threshold of the AFeTFT increases, the threshold window of the trigger shifts positively. Tunable threshold window enables the Schmitt trigger to meet diverse performance requirements in complex circuits.