A conduction model for polysilicon thin films over a wide doping level range

¹ School of Electronic and Information Engineering, State Key Lab of Luminescence Materials and Devices, South China University of Technology, Guangzhou 510640, P.R. China
² College of Material Science and Engineering, State Key Lab of Luminescence Materials and Devices, South China University of Technology, Guangzhou 510640, P.R. China

^a e-mail: phlibin@scut.edu.cn

Received: 4 August 2010
Revised: 3 April 2011
Accepted: 19 October 2011
Published online: 23 December 2011

Abstract

In this paper, based on diffusion and thermionic-field emission conduction mechanisms in crystalline-insulator-crystalline system, a comprehensive model of current conduction for polycrystalline silicon is developed, considering the doping effect and the temperature effect on carrier mobility. The simulation results show a good agreement with the experimental data without unphysical fitting parameter. It is demonstrated that the effective diffusion velocity limits the carrier movement at light doping level, while the thermal velocity and the tunneling effect dominate the carrier conduction at heavy doping concentration. The developed model can interpret the conduction characteristics of polysilicon thin films over a wide range of doping levels with temperature.