(Digital Presentation) Degradation and Recovery of Low Temperature Poly-Si Thin Film Transistors Under DC and AC Bias Stresses

Abstract

The degradation and recovery phenomena of n-type LTPS TFTs stressed at hot carrier effect region under various bias conditions are investigated. The devices with longer LDD’s length demonstrate less degradation ratio but more recovery ratio, because of the lower transverse electric field. As the AC signals are applied to the gate terminal, the degradation of devices shows no significant dependence of AC signal frequency, but the recovery ratio displays the similar trends as AC signal frequency changing. However, as the AC signals are applied to the drain terminal, the degradation of devices shows very significant dependence of AC signal frequency. The higher the AC signal frequency is, the less degradation the devices show, but the recovery ratio displays the similar trends as AC signal frequency changing. From the results of all stressing conditions, the LTPS TFTs stressed with DC voltages exhibit the largest degradation ratio but almost the least recovery one.