Novel Silicon-Based Flash Cell Structures for Low Power and High Density Memory Applications (invited)

摘要

Scaling down of conventional flash memory technology faces difficult technical challenges and some physical limitations. Novel silicon-based flash cell structures were presented in this paper as possible solutions. A novel cell structure using dual doping polysilicon (PNP) as the floating gate is proposed and experimentally exhibit higher programming speed and better data retention characteristics in comparison with conventional n-type floating-gate structure. To further enhance storage density and relax the stringent requirements of scaling, a novel vertical channel dual-nitride-trapping-layer ROM (VDNROM) as a kind of SONOS flash is proposed and experimentally demonstrated. Compared with conventional planar NROM cell, VDNROM structure can have high capability of cell area shrinking and achieve four-physical-bit per cell storage capability. The fabrication technologies of the two novel devices are fundamentally compatible with standard CMOS process.