Authors: L. Larcher, A. Padovani, P. Pavan
Affilation: Università di Modena e Reggio Emilia, Italy
Pages: 809 - 814
Keywords: charge transport, leakage current, high-k, trap-assisted tunneling, compact modeling, resistive ram
First, we present a Monte-Carlo model we developed for describing the charge transport in hafnium-based stacks, which allows reproducing voltage and temperature dependencies of the leakage current along with its statistical distribution. The model accounts for the structural relaxation associated with the charge capture/emission processes and it takes into account the contributions of conductive paths comprised of multiple defects, which are randomly generated within the oxide. Second, we worked on this model in order to make it implementable into Spice-like circuit simulators. To this purpose, the equations describing the rate of the charge transport through defects have been calculated by assuming that defects are uniformly distributed within the dielectric volume. This allows calculating the current as a function of the density and the energy level of defects, neglecting the contribution of multiple-defect percolation paths. Despite such simplifying assumptions, this compact model reproduces quite accurately the average experimental current. In addition, it can be used for a preliminary evaluation of the gate current variability due to the variation of defect energy.