Novel model of electrical conduction property at grain boundary in polysilicon

A new model of the potential barrier distribution at a grain boundary (GB) is developed by Gaussian function, by which an improved expression is presented for the current-voltage relationship to explain the electrical properties of polysilicon. The GB is considered to be that of amorphous and microcrystalline silicon. The GB plays a dominant role in determining the electrical properties of polysilicon. The variation of the resistivity in polysilicon with respect to the dopant concentration and the potential barrier height has been investigated. The results show that the resistivity increases with the barrier height at the GB. Furthermore, the GB resistivity (ρgb) is much larger by two or three orders than the resistivity (ρ) in a grain when the grain size is about 102 nm. In addition, ρgb and ρ decrease with increasing dopant concentration at a constant potential barrier height.