Influence of Si(100) surface flattening process on nonvolatile memory characteristics of Hf-based MONOS structures

Metal-oxide-nitride-oxide-silicon (MONOS) type memory is a promising candidate to replace the conventional floating-gate (FG) type non-volatile memory [1]. Even for MONOS memory with high-k gate stacks, such as the in-situ formation of Hf-based MONOS structure, the scaling is necessary to reduce the operating voltage [2]. However, as the gate stacks scaling, the interface roughness at the gate insulator/Si is one of the critical issues to obtain the high reliability and performance of MIS devices [3]. In our previous report, atomically flat Si(100) surface was formed by annealing in Ar/H₂ ambient for the first time [4]. In this study, electrical characteristics of Hf-based MONOS structure on atomically flat Si(100) surface were investigated.