ABSTRACT
This chapter discusses a type of MSUM cell which integrates a vertical channel DRAM gain cell with a traditional nonvolatile memorie (NVM) cell. It describes several band-engineered DTM-based CT-MSUM cells. The chapter references recently published multilayered conductive floating-gate/floating-plate MSUM stack designs demonstrating simultaneous DRAM/NVRAM functionality. The chapter outlines band-engineered nanocrystal-based MSUM device design concepts and as well as reverse mode MSUM device design concepts. A brief review of other silicon based multifunctional memories developed and published recently is being made here. Some of these concepts could be classified within the general definition of MSUM devices. Regardless of the terminology, such emergence of multifunctional devices is expected to widen the application frontiers of the nonvolatile memories in future years. MSUM designs which combine the nanocrystal trapping with dielectric trapping and selected high trap density deep offset dielectric films have the advantages of both. Such devices have been proposed to achieve multifunctional and MLC capability simultaneously.
