Reliability analysis for flexible electronics

Abstract

Flexible electronics fabricated on thin-film, lightweight, and bendable substrates (e.g., plastic) have great potential for novel applications in consumer electronics such as flexible displays, e-paper, and smart labels; however, the key elements, namely thin-film transistors (TFTs), for implementing flexible circuits often suffer from electrical instability. Therefore, thorough reliability analysis is critical for flexible circuit design to ensure that the circuit will operate reliably throughout its lifetime. In this article we propose a methodology for reliability simulation of hydrogenated amorphous silicon (a-Si:H) TFT circuits. We show that: (1) the threshold voltage ( V TH ) shift of a single TFT can be estimated by analyzing its operating conditions; and (2) the circuit lifetime can be predicted accordingly by using SPICE-like simulators with proper modeling. We also propose an algorithm to reduce the simulation time by orders of magnitude, with good prediction accuracy. To validate our analytical model and simulation methodology, we compare simulation results with the actual circuit measurements of an integrated a-Si:H TFT scan driver fabricated on a glass substrate and we demonstrate very good consistency.