Direct Measurement of Back-Tunneling Current during Program/Erase Operation of Metal–Oxide–Nitride–Oxide–Semiconductor Memories and Its Dependence on Gate Work Function

Abstract

In this study, we have established a novel scheme to extract the back-tunneling current from the transient characteristics of a metal–oxide–nitride–oxide–semiconductor (MONOS) memory capacitor during programming or erasing. Using a charge centroid extraction method, the separation of trapping current, leakage current and back-tunneling current was successfully accomplished. By studying the gate work function dependence of injected current, it was found that the leakage current due to electron injection from the Si substrate is the dominant component during deep programming and that the back-tunneling current due to electron injection from the gate electrode is the predominant component of injected current during deep erasing.