Extended Cyclability in Electrically-Alterable Read-Only-Memories

Abstract

An electrically-alterable read-only-memory using silicon dioxide and silicon-rich silicon dioxide layers capable of being cycled ≳ 107 times by minimizing election charge trapping in the SiO2 layers of the device by incorporation of small amounts of silicon is reported for the first time. Charge transfer to and from a floating polycrystalline silicon layer from a control gate electrode is accomplished by means of a modified dual-electron-injector-structure stack. This modified stack has the intervening silicon dioxide layer, which is sandwiched between silicon-rich silicon dioxide injectors, replaced by a slightly off-stoichiometric oxide containing between 1% and 6% excess atomic silicon above the normal 33% found in silicon dioxide. A brief discussion of a physical model which is believed to account for the observed phenomenon is given. Copyright © 1982 by The Institute of Electrical and Electronics Engineers, Inc.