Dynamic stressing of thin tunnel oxides: a way to emulate a single EEPROM cell programming function

An experimental set-up was implemented by which metal-oxide-semiconductor ( MOS) capacitors are subjected to bipolar high voltage (up to 20 V) pulses s imilar to those used in programming electrically erasable programmable read -only memory (EEPROM) devices. Thin (9 nm) tunnel SiO2 oxides MOS capacitor s were used. During stress, by means of capacitive coupling, the capacitors gate node was kept floating so its potential was equivalent to that of the isolated floating gate of a memory cell. The written and erased operations of memory cells which are based on Fowler-Nordheim (FN) tunneling injectio n mechanisms, were then reproduced on simple MOS capacitors. Via a high inp ut impedance electronic circuit, the floating gate potential was monitoring . A model based on a simple equivalent electrical circuit was used to simul ate the transient regime of the FN current and the resulting floating gate charge and potential during dynamic stressing. It was shown that the Boatin g gate accumulated charge is proportional to the maximum control gate volta ge but is independent of the control gate pulse rise time. (C) 1999 Elsevie r Science B.V. All rights reserved.