A new charge-trapping nonvolatile memory based on the re-oxidized nitrous oxide

We report for the first time on feasibility of a re-oxidized nitrous oxide (N2O) as gate dielectric for charge-trapping nonvolatile memory. Ultra-thin oxide is grown directly on silicon substrate in a N2O ambient. The N2O oxide is then in situ re-oxidized in O2. This process is performed in a rapid thermal processor. After re-oxidation, the nitrogen distributions show two peaks, which consist of first peak at the initial Si-SiO2 interface and second peak at the growing Si-SiO2 interface. The second nitrogen peak is caused by diffusion of some of nitrogen toward the growing Si-SiO2 interface. The nitrogen incorporated in oxide bulk act as charge traps, and the nitrogen increased at the new Si-SiO2 interface improves interface stability. The re-oxidized N2O oxides show maximum memory window of about 0.55 V and the excellent dielectric breakdown. Oxide/nitrogen-rich layer/oxide structure can be applicable as gate dielectric for not only metal-oxide-semiconductor device, but also charge-trapping nonvolatile memory.