Modeling of the nonuniform channel characteristic of a-Si:H thin film transistor under saturation mode bias temperature stress

摘要

Understanding the importance of behavior of TFT characteristics under various electrical bias, in the paper, non-uniform channel characteristic of the aSi:H TFT caused by saturation mode Bias Temperature Stress (BTS) has been investigated. By assuming two exponential profiles of density of states within the band gap, a physical based model using a quasi-twodimensional approach has been derived. Parameter n has been introduced to the non-uniform distribution of the lateral electric field. Both the simulation and calculated results are finally verified with the experiment data. A good agreement is obtained. The work is helpful in understanding of drain bias dependence of threshold voltage stability of amorphous silicon TFTs.