Simulation of a long term memory device with a full bandstructure Monte Carlo approach

Simulations of charging characteristics of a long term memory device, based on a floating gate structure, are presented. The analysis requires the inclusion of hot electron effects and a detailed account of the semiconductor bandstructure, because device operation is based on the injection of electrons into the gate oxide high above the silicon conduction band edge. We have developed a Monte Carlo simulator based on a full bandstructure approach which accurately accounts for the high energy tail of the electron distribution function. For practical simulation of the prototype structure, with 3.0-pm source-drain separation, the simulator is used as a post-processor on the potential profile obtained from a PISCES IIB drift-diffusion solution. The computations are in quantitative agreement with experimental results for the gate injection current, measured at fixed drain and gate biases.