Light Effects on Charge Trapping and Detrapping of nc-ZnO Embedded ZrHfO High-k MOS Nonvolatile Memories

Abstract

MOS capacitors containing the nanocrystalline ZnO embedded Zr doped HfO2 high-k gate dielectric film integrated with the indium tin oxide gate electrode have been fabricated and characterized under the dark and light exposure conditions for nonvolatile memory properties. When measured in dark, the capacitor had a large charge storage capacity showing a counterclockwise capacitance-voltage hysteresis. When exposed to the light, the memory capacity was increased. The generation and transfer of electrons and holes in and from the nanocrystalline ZnO under the light exposure condition are responsible for the memory window change and charge retention characteristics.