EFFECT OF THE ACTIVE LAYER THICKNESS ON THE LEAKAGE CURRENT IN P+P P+ACCUMULATION POLYCRYSTALLINE SILICON TFTS

The variations of the resistive and generation components of the leaka ge current in p+p p+ accumulation polycrystalline silicon TFTs as func tions of the active film thickness are analyzed. A simple electrostati c 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-enhanc ed generation current depend on both carrier trapping at grain boundar ies and electrostatic coupling between interfaces, between interfaces and parallel grain boundaries, when they exist, and between parallel a nd perpendicular grain boundaries.