An alternative method for the formation of the top oxide in oxide-nitride-oxide dielectric stacks is proposed. This method combines low-energy silicon ion implantation into a thin nitride-oxide stack and subsequent low-temperature wet oxidation ( for ). Transmission electron microscopy shows that for an implanted dose of , an -thick silicon oxide layer develops on the surface of the nitride-oxide stack. Time of flight secondary ion mass spectrometry reveals: (1) transformation of the implanted silicon nitride to an oxygen-rich-silicon nitride layer and (2) pilling up of nitrogen atoms at the bottom silicon/oxide-substrate interface. The resulting oxide-nitride-oxide stack exhibits strong charge storage effects and excellent charge retention properties leading to a , extrapolated memory window at . These results suggest that the proposed fabrication route may lead to gate dielectric stacks of substantial potential impact for mainstream nitride-based memory devices.
Wet oxidation of nitride layer implanted with low-energy Si ions for improved oxide-nitride-oxide memory stacks
V. Ioannou-Sougleridis, P. Dimitrakis, V. Em. Vamvakas, P. Normand, C. Bonafos, S. Schamm, N. Cherkashin, G. Ben Assayag, M. Perego, M. Fanciulli; Wet oxidation of nitride layer implanted with low-energy Si ions for improved oxide-nitride-oxide memory stacks. Appl. Phys. Lett. 25 June 2007; 90 (26): 263513. https://doi.org/10.1063/1.2752769
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