Effect of energy-band bending induced by precipitation of ZrO2 nanocrystals on memory characteristics of charge-trap flash memory

Charge-trap flash-memory capacitors incorporating Zr0.7Si0.3Ox and Zr0.6Si0.4Ox films as the charge-trapping layer were fabricated and investigated. The Zr0.7Si0.3Ox trapping layer exhibited a large memory window of 11.2 V, good retention characteristics, and a higher program/erase speed than the Zr0.6Si0.4Ox trapping layer. The remarkable improvement of the memory characteristics are attributed to the ZrO2 nanocrystals that precipitated from the Zr0.7Si0.3Ox matrix after the annealing treatment, inducing the redistribution of the elemental compositions and the energy-band bending. The results indicate that the bended-energy-band Zr0.7Si0.3Ox trapping layer is a promising candidate for future nonvolatile-memory applications.