Can 2D-Nanocrystals Extend the Lifetime of Floating-Gate Transistor Based Nonvolatile Memory?

Conventional floating-gate (FG) transistors (made with Si/poly-Si) that form the building blocks of the widely employed nonvolatile flash memory technology face severe scaling challenges beyond the 12-nm node. In this paper, for the first time, a comprehensive evaluation of the FG transistor made from emerging nanocrystals in the form of 2-dimensional (2D) transition metal dichalcogenides (TMDs) and multilayer graphene (MLG) is presented. It is shown that TMD based 2D channel materials have excellent gate length scaling potential due to their atomic scale thicknesses. On the other hand, employing MLG as FG greatly reduces cell-to-cell interference and alleviates reliability concerns. Moreover, it is also revealed that TMD/MLG heterostructures enable new mechanism for improving charge retention, thereby allowing the effective oxide thickness of gate dielectrics to be scaled to a few nanometers. Thus, this work indicates that judiciously selected 2D-nanocrystals can significantly extend the lifetime of the FG-based memory cell.