Nonvolatile Memory Characteristics of CdS Embedded Zr-Doped HfO2 High-k Dielectric MOS Capacitors

Abstract

Nonvolatile memory device characteristics of the MOS capacitor containing the CdS embedded ZrHfO high-k gate dielectric layer have been investigated. The embedded CdS layer suppressed the growth of the high-k/Si interface layer and generated a large amount of charge trapping sites. The device preferred to trap holes under the negative voltage stress condition than electrons under the positive stress condition. The hole trapping density increased with the increase of stress time. The current density-voltage curve results confirmed the hole trapping mechanism and the quick release of shallow trapped holes upon the release of the stress voltage. More than 48% of the originally trapped charges remained in the devices after 10 years. The CdS embedded ZrHfO gate dielectric is a suitable structure for nonvolatile memories.