Numerical analysis for root-mean-square roughness of SiO2/Si interface on direct tunneling current in ultrathin MOSFETs

Interface roughness effects on direct tunneling current in ultrathin MOSFET s are investigated by numerical analysis. The interface roughness is descri bed in terms of Gauss distribution. It is shown that the effects of rough s urface on tunneling current cannot be neglected while tunneling occurs in t he regime of direct tunneling. The effects increase exponentially with oxid e thickness or applied voltage across oxide decreasing. This means that the effects become more and more important while the direct tunneling current takes up the main contribution to the gate leakage current. (C) 2001 Elsevi er Science Ltd. All rights reserved.