Categorization of Multilevel-Cell Storage-Class Memory: An RRAM Example

This paper provides new insights into the effect of device characteristics on multilevel-cell (MLC) operation, aiming at potential benefits, such as the reduction of write latency and peripheral circuit design overhead. A general categorization of the MLC-operating schemes in storage-class memory (SCM) is proposed to connect the total number of write inputs with fundamental device properties. The categorization method is validated using two resistive random access memory devices based on different switching mechanisms. Favorable device characteristics and the corresponding simplified MLC operating schemes are addressed to facilitate future development of MLC SCM.