Study of the current-voltage characteristics in MOS capacitors with Si-implanted gate oxide

The specific gate current density (J(G)) Versus voltage (VG) characteristics of MOS capacitors with 50 nm thick, implanted SiO2 (using various Si doses between 10(13) and 3 x 10(16) cm(-2)) have been studied under inversion and accumulation conditions. From an analysis of dynamic resistance and current humps in the J(G)-V-G characteristics of the above devices, a qualitative model of the conduction mechanism has been proposed. Major current components in the model are the following: a direct tunnel current of electrons and holes related to traps generated by Si-implantation, a charging current of electrons and holes to traps distributed a little inside the gate oxide, a trap-assisted current and a Fowler-Nordheim tunnel current. The model can explain the J(G)-V-G curves and the change of the J(G)-V-G characteristics on the basis of the Si atomic distribution in the gate oxide. (C) 1999 Elsevier Science Ltd. All rights reserved.