Reliability of nc-ZnO Embedded ZrHfO High-kNonvolatile Memory Devices Stressed at High Temperatures

Abstract

AbstractThe nanocrystalline ZnO embedded Zr-doped HfO2high-kdielectric has been made into MOS capacitors for nonvolatile memory studies. The device shows a large charge storage density, a large memory window, and a long charge retention time. In this paper, authors investigated the temperature effect on the reliability of this kind of device in the range of 25°C to 175°C. In addition to the trap-assisted conduction, the memory window and the breakdown strength decreased with the increase of the temperature. The high-k film's conductivity increased and the nc-ZnO's charge retention capability decreased with the increase of temperature. The nc-ZnO retained the trapped charges even after the high-k film broke down and eventually lost the charges at a higher voltage. The difference between these two voltages decreased with the increase of the temperature.