Monte Carlo Simulation of Flash Memory Elements’ Electrophysical Parameters

Abstract

Operation of modern flash memory elements is based on electron transport processes in the channel of silicon MOSFETs with floating gate. The aim of this work was calculation of electron mobility and study of the influence of phonon and ionized impurity scattering mechanisms on the mobility, as well as calculation of parasitic tunneling current and channel current in the conductive channel of flash memory element. Numerical simulation during the design stage of flash memory element allows working out guidelines for optimization of device parameters defining its performance and reliability. In the work such electrophysical parameters, characterizing electron transport, as mobility and average electron energy, as well as tunneling current and current in the channel of the flash memory element are studied via the numerical simulation by means of Monte Carlo method. Influence of phonon and ionized impurity scattering processes on electron mobility in the channel has been analyzed. It is shown that in the vicinity of drain region a sufficient decrease of electron mobility defined by phonon scattering processes occurs and the growth of parasitic tunneling current is observed which have a negative influence on device characteristics. The developed simulation program may be used in computer-aided design of flash memory elements for the purpose of their structure optimization and improvement of their electrical characteristics.