Effects of grain-boundary trapping-state energy distribution on the activation energy of resistivity of polycrystalline-silicon films

The trapping model assuming a δ-function energy distribution of trapping states has been accepted as an effective first-order approximation for modeling the electrical properties of polysilicon films. However, it predicts that as the doping concentration N is smaller than a critical level N*, the activation energy of resistivity Ea is independent of N. This is inconsistent with experimental observations. In this paper a trapping model using a Gaussian energy distribution of trapping states is introduced to calculate Ea vs N. The results demonstrate a good agreement with the experimental data of boron-doped polysilicon films. The physical bases of such an improvement and the existence of a Gaussian energy distribution of trapping states have been addressed. © 1984.