In this paper, the inter-poly dielectric (IPD) thickness, scaling, and reliability characteristics of Al2O3 and HfO2 IPDs are studied, which are then compared with TEOS IPD. Regardless of deposition tools, drastically leakage current reduction and reliability improvements have been demonstrated by replacing TEOS IPD with high-permittivity (high-κ) IPDs, which are suitable for mass production applications in the future. Moreover, MOCVD deposition can be used to further promote dielectric reliability when compared to reactive-sputtering deposition. By using MOCVD deposition, the QBD can be significantly improved, in addition to reduced leakage current density, enhanced breakdown voltage and effective breakdown field. Our results clearly demonstrate that both MOCVD-Al 2O3 and MOCVD-HfO2 IPD possess great potential for next generation stacked-gate flash memories.