Effect of SiO2/Si interface roughness on gate current

In many theoretical investigations of the electric-tunnel effect through an ultrathin oxide in metal-oxide-semiconductor (MOS) structure, it is common ly assumed that the oxide is of uniform thickness. One example of nonunifor mity in oxides is interface roughness. Interface roughness effects on direc t tunneling current in ultrathin MOS structures are investigated theoretica lly in this article. The rough-ness at SiO2/Si interface is described in te rms of Gauss distribution. It is shown that the transmission coefficient in creases with root-mean-square (rms) roughness increasing, and the effect of rms roughness on the direct tunneling current decreases with the applied v oltage increasing and increases with rms roughness increasing, (C) 2001 Els evier Science Ltd. All rights reserved.