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Takeki NINOMIYA Zhiqiang WEI Shinichi YONEDA Kenji SHIRAISHI
We considered the oxygen diffusivity around a conductive filament of resistive switching oxides, with the aim of designing material appropriate for highly reliable non-volatile memory. Both theoretical and experimental analyses were performed for this consideration. The theoretically obtained oxygen chemical potential difference, which works as a driving force for diffusion, significantly depends on a material. Then, we experimentally confirmed that the oxygen diffusion behaviors vary greatly depending on the chemical potential differences.
Akira OTAKE Keita YAMAGUCHI Katsumasa KAMIYA Yasuteru SHIGETA Kenji SHIRAISHI
Due to the aggressive scaling of non-volatile memories, “charge-trap memories” such as MONOS-type memories become one of the most important targets. One of the merits of such MONOS-type memories is that they can trap charges inside atomic-scale defect sites in SiN layers. At the same time, however, charge traps with atomistic scale tend to induce additional large structural changes. Hydrogen has attracted a great attention as an important heteroatom in MONOS-type memories. We theoretically investigate the basic characteristics of hydrogen-defects in SiN layer in MONOS-type memories on the basis of the first-principles calculations. We find that SiN structures with a hydrogen impurity tend to reveal reversible structural change during program/erase operation.