Effects of high-temperature O _2 annealing on Al _2O _3 blocking layer and Al _2O _3/Si _3N _4 interface for MANOS structures

摘要

In this paper, we have investigated the effects of O _2 post-deposition annealing (PDA) on metal/Al _2O _3/Si _3N _4/SiO _2/Si (MANOS) devices. Compared with low-energy plasma oxygen pre-treatment and the N _2 PDA process, the O _2 PDA process can lead to a significant retention improvement. The improvement is attributed to the removal of oxygen vacancies in Al _2O _3 block oxide and the oxygen incorporation at the Si _3N _4/Al _2O _3 interfacial layer which is determined by x-ray photoelectron spectroscopy (XPS) depth profiling and electrical characteristics. Metal/Al _2O _3/SiO _2/Si (MAOS) devices are also studied to confirm these effects. As a result, we consider that the O _2 PDA process is a crucial process for future MANOS-type memory devices.