Novel Oxynitride Layer Applied to Flash Memory using HfO2 as Charge Trapping Layer

When the thickness of tunnel oxide layer is thinner than 7 nm, the defects of tunnel oxide will form the leakage path easily. The trapped charges in trapping layer leak out through the leakage path and let we read the wrong data information. Therefore, the novel oxynitride process has been proposed to improve the reliabilities of flash memory by reducing the interface states and bulk defects. Moreover, the novel oxynitride process is compatible with standard CMOS process today and it is practicable improvement in industry manufacturing. The HfO₂ layer was used as charge trapping layer. At first we found the better PDA conditions of HfO₂ film from the test capacitors and applied the optimum condition in integrated flash memory devices. Finally, the complete electrical measurements and analysis were carried out. From the result of this study, the oxynitride can promote the reliabilities of flash memory by improving the quality of tunnel oxide.