A new dual floating gate flash cell for multilevel operation

A new dual floating gate flash memory cell using constant bias voltages for multilevel operation is proposed to increase memory density. Channel hot e lectrons (CHE) and drain avalanche hot electrons (DAHE) are used to store d ifferent amounts of charge in different floating gates. To erase the data, channel fowler-nordheim (FN) tunneling is applied first, and then substrate hot electron (SHE) injection is utilized to prevent from over erase and ti ghten the threshold voltage spread. The simulation results indicate that th e multilevel flash memory cell with slight modifications of triple well tec hnology is a promising device for future multilevel operation devices.