Memory Effect of Metal-Oxide-Silicon Capacitors with Self-Assembly Double-Layer Au Nanocrystals Embedded in Atomic-Layer-Deposited HfO₂ Dielectric

We report the chemical self-assembly growth of Au nanocrystals on atomic-layer-deposited HfO₂ films aminosilanized by (3-Aminopropyl)-trimethoxysilane aforehand for memory applications. The resulting Au nanocrystals show a density of about 4×10¹¹cm^-2 and a diameter range of 5-8nm. The metal-oxide-silicon capacitor with double-layer Au nanocrystals embedded in HfO₂ dielectric exhibits a large C-V hysteresis window of 11.9V for ± 11V gate voltage sweeps at 1MHz, a flat-band voltage shift of 1.5V after the electrical stress under 7V for 1ms, a leakage current density of 2.9×10^-8 A/cm^-2 at 9V and room temperature. Compared to single-layer Au nanocrystals, the double-layer Au nanocrystals increase the hysteresis window significantly, and the underlying mechanism is thus discussed.