Fabrication of nano-floating gate memories through atomic layer deposition incorporated with chemically-synthesized ZnO-nanocrystals

Nano-floating gate memories made of Al2O3/ZnO/Al2O3 nanostructures were fabricated with chemically-driven ZnO nanocrystals embedded into high-k Al2O3 thin films prepared through atomic layer deposition. The memory characteristics were analyzed through high-frequency capacitance–voltage measurement and current–voltage characteristics, along with high-resolution images of the aforementioned structures. The dotted ZnO nanocrystals function as charge-trapping/detrapping centers, inducing a very large memory window of 5.34 V. The defective nature of ZnO was optimally adjusted into the energy-band diagrams in combination with the tunneling and control layers of the robust Al2O3 thin films. The measured memory characteristics exhibited superior retention features derived from the charge-trapping/detrapping behaviors.