Physical Modeling of Photonic Characteristics in Amorphous Oxide TFTs Incorporating Trap State Excitation and Carrier Percolation

Abstract

In this study, an analytic physical model for the photonic behavior of amorphous oxide semiconductor thin film transistors (AOS TFTs) under laser-induced stress is proposed, addressing stability impacts through both trap state excitation and carrier percolation. The model describes the subgap density of states (DOSs) using exponential band tail states and Gaussian deep states, which capture the effects of various light-induced trap states within the AOS bandgap. Additionally, it employs percolation theory based on a random mobility edge (RME) hypothesis, incorporating the critical parameter of percolation threshold to optimize the existing mobility calculation formula. An electrical testing system was established, and AOS TFTs featuring an etch stop layer (ESL) were fabricated to verify the proposed model. Validation against experiment confirms the model’s ability to accurately predict the photonic response of AOS TFTs under laser irradiation at different wavelengths.