Characterization of trap dynamics via transient response in amorphous InGaZnO thin-film transistors

Abstract

In this paper, the transient behavior of amorphous InGaZnO thin-film transistors is quantitatively investigated to clarify the charge trapping dynamics limiting high-speed operation. The transient drain current response is characterized by varying the gate pulse duration (t(p)) and the operating temperature (T). A power law-based model is employed to extract key parameters (alpha J(T0,i), Q(T,i), and n(i)), revealing two temporal regimes separated at t(o) approximate to 7 & times; 10(-3 )s. The fast regime (R1) is governed by tunneling-mediated electron capture into shallow traps, whereas the slow regime (R2) originates from thermally assisted transport into deeper traps under electrostatic coupling to accumulated trapped charge. A clear transition in R2 response occurs near T approximate to 333 K. Activation energy (E-a) analysis yields Ea approximate to 0 eV in R1 and E-a = 0.2-0.4 eV in R2 for low T, indicating a transition from tunneling to hopping conduction. These results provide a compact framework for separating fast/slow trapping and optimizing oxide thin-film transistor operation.