Dynamic Analysis of the Negative OFF-State Current in Thin-film Transistors

Negative drain currents under positive drain-to-gate voltage were found in the OFF-state transfer curves of thin-film transistors (TFTs). A dynamic model was developed, by accounting for capacitances, to interpret the phenomenon. The capacitor discharging during gate voltage sweeping leads to the negative currents. Test conditions and intrinsic device parameters affect the existence of this phenomenon, which is verified by our experimental results of InGaZnO TFTs.