Improved Retention for a Al2O3 IPD Embedded Flash Cell without Top-Oxide

Using a 2Mb embedded Flash cell array as a demonstrator, we reported previously that a 3 V reduction in programming voltage was possible by replacing the ONO inter- poly dielectric (IPD) with an IPD comprising the high-k material, AI₂O₃ by Kakoschke, R., et al, (2007). Adding a thin protective top-oxide to the high-k IPD was later shown to significantly improve reliability in Power, J. R., et al, (2007). In this paper, we show that for integration schemes more suited to the material properties of AI₂O₃, reliably functioning 2 Mb demonstrators with a high-k IPD but without top-oxide protection are also feasible.