Degradation of solution based metal induced laterally crystallized p-type poly-si TFTs under DC bias stresses

Device degradation of solution based metal-induced laterally crystallized (MILC) p-type poly-Si thin film transistors (TFTs) is studied under DC bias stresses, which is found to be dominated by negative bias temperature instability (NBTI) mechanism. While standard NBTI or electron injection (EI) is observed under -V_g or -V_d only stress, respectively, a mixed NBTI and EI degradation is observed under combined low -V_g and -V_d stresses. Under high -V_d and moderate -V_g stress, pure hot carrier (HC) degradation cannot be observed, but a combined degradation of NBTI and HC occurs. Grain boundary (GB) trap generation is found to correlate with the NBTI degradation with the same time exponent, suggesting the key role of GB trap generation in poly-Si TFTs' degradation. © 2008 IEEE