Effect of the active layer thickness on the leakage current in p +p p + accumulation polycrystalline silicon TFTs

Abstract

The variations of the resistive and generation components of the leakage current in p +p p + accumulation polycrystalline silicon TFTs as functions of the active film thickness are analyzed. A simple electrostatic model of the studied structure and of its silicon layer, associated with a numerical method of solving the 2D Poisson equation, allows us to show that the resistivity of the film and the electric field-enhanced generation current depend on both carrier trapping at grain boundaries and electrostatic coupling between interfaces, between interfaces and parallel grain boundaries, when they exist, and between parallel and perpendicular grain boundaries.