| When ELA technology is used the formation of poly-crystalline silicon thin film materials is affected by the laser energy density, including the formation of defects, the life of carriers and poly-Si structure morphology. It is a pressing problem to determine what kind of laser energy can provide an optimal thin-film transistor(TFT) performance.In order to solve this problem, we adopt the ATLAS simulation tools to evaluate the electrical properties of poly-Si TFTs and find out how the different energy density affects poly-Si material and the optimum conditions at the same time. In this work, we will fabricated poly-Si TFTs with different laser energy densities and characterize their electrical characteristics.An appropriate simulation model determines whether we can fit of the electrical properties correctly. There are a large number of grain boundaries between in poly-Si TFT active layer and the traps capture carrier,which make a lot of difficulties and complexities in modeling poly-Si TFTs. There a lot about poly-Si electrical characteristics of the industry model, but is not standard. Leakage of electric current model is not perfect especially. This work will introduce conductivity model, the mobility model, discrete boundary model and the leakage current model. Like the space charge limited current, trap auxiliary thermionic field emission, field enhanced thermal emission and interband tunneling leakage mechanism and field emission theory model of hot electron field emission theory model, thermionic field emission contains Poole-Frenkel effect theory of emission model. Finally using the above models for ELA poly-Si TFT’s characteristic curve fitting, we can get the change of the related parameters and determine the polycrystalline silicon thin film transistor characteristics under different energy density changes. Thus we could extract the density of states(DOS) in the ELA poly-Si film reasonably. |
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