Determination of the concentration of hot-carrier-induced bulk defects in laser-recrystallized polysilicon thin film transistors

摘要

We present a method to investigate hot carrier induced defects in laser recrystallized polysilicon thin film transistors, based on the use of a structure with front and back gate and the analysis of the off current. The maximum process temperature for these devices was 425℃. We find that both positive and negative V_(GS) produce similar degradation of the characteristics and the main effect is bulk, rather than interface, state creation. The changes in the 1-V characteristics are accounted for by an increase of the dangling bond concentration, which is obtained as a fitting parameter, giving a good agreement between experiment and simulation.