Investigation of multi-level-cell and SET operations on super-lattice phase change memories

Abstract

This paper gives the optimum SET pulse with the investigation on SET current delay and the multi-level-cell (MLC) operation for super-lattice phase change memories (SL-PCMs). From the investigation, the voltage, or the electric field triggers RESET/SET transition of SL-PCM. The induced energy is also essential for changing the resistance state. In this paper, the MLC operation is also verified with RESET pulse, 1-step SET pulse and 2-step SET pulse. The measurement results indicate the 2-step SET pulse is the best for the MLC function, which realizes the precise resistance controlling. Additionally, the retention-time is measured to evaluate the reliability of MLC SL-PCM. The features of SL-PCM are not only small RESET/SET current, but also MLC operation and the SL-PCM technology provides a potential for next generation non-volatile memories.