Nonvolatile Memories Based on Nanocrystalline Zinc Oxide Embedded Zirconium-doped Hafnium Oxide Thin Films

Abstract

Memory devices containing nanocrystalline ZnO embedded Zrdoped HfO2 high-k dielectric films have been prepared and characterized. The memory effect was manifested by the large counterclockwise capacitance-voltage hysteresis, e.g., 1.22V at {plus minus}6V gate bias, and negative differential resistance region in the positive bias current-voltage range. The maximum trapped charge density of 6.43 ×1012cm-2 was obtained after -9V→ +9V→ -9V sweeps. The memory effects were mainly caused by electron trapping at low bias voltage. A large memory operation window, e.g., 0.90 V, with a long charge retention time, e.g., > 36,000s, was achieved under the proper gate stress voltage. It is a viable dielectric for future nano-size metal oxide semiconductor field effect transistors and capacitors.