Highly reliable TaO x ReRAM with centralized filament for 28-nm embedded application

For 28-nm embedded application, we have proposed a TaO x -based ReRAM with precise filament positioning and high thermal stability. The cell was realized using several newly-developed process technologies and cell structures: low-damage etching, cell side oxidation and encapsulated cell structure. As a result, we succeeded for the first time in forming a filament at the cell center. In addition, we confirmed the feasibility of 20-nm cell size. Excellent reliability was achieved in 2-Mbit 40-nm ReRAM: 100k cycles and 10 years' retention at 85 °C was demonstrated.