Skip to Main Content
Substrate current (Isub) in poly-Si thin film transistors (TFTs) is first investigated by considering their specific substrate contact configuration. When the substrate bias is very small, Isub is driven by the recombination process in the channel region and is related to the trap density (Dt) wherein. Controlled by the gate bias (Vg), the recombination region varies from the whole channel area to a localized region near the drain, source or substrate terminal. Based on such observation, Isub is used to monitor the hot carrier degradation in TFTs. The Isub-Vg curve is applied to sensitively reflect the location of the hot carrier-induced damage region and evaluate the local Dt increase wherein.