This work presents an alternative method for the formation of the top oxide in oxide-nitride-oxide structures. The method utilizes low-energy (1 keV) Si ion implantation into thin oxide-nitride stacks, followed by low temperature wet oxidation. Transmission electron microscopy examination clearly indicates the formation of a three-layer structure, verified also by Time-of flight secondary ion mass spectrometry. The electrical characteristics of the oxide-nitride-oxide stacks exhibit strong trapping effects and excellent retention characteristics resulting to a 1.5 V 10-year memory window at 125 °C.