Transient Effect Assisted NBTI Degradation in p-Channel LTPS TFTs under Dynamic Stress.

This work investigates dynamic negative bias temperature instability (NBTI) in p-channel low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) with different rise and fall times. Experimental results reveal identical increases in the interface state density (N_it) induced by different dynamic NBTI stress conditions. Nevertheless, the degradation of the grain boundary trap (Nt_rap) becomes more significant as rise time decreases to 1 μs. Because the surface inversion layer cannot form during the short rise time, transient bulk voltage will cause excess holes to diffuse into the poly-Si bulk. Therefore, the significant N_trap increase is assisted by this transient effect. [ABSTRACT FROM AUTHOR]