Polycrystalline silicon multi-functional memory (MFM) with a recessed channel structure

Abstract

A channel recessed multi-functional memory using a polycrystalline-silicon thin-film floating body and SiO2/Si3N4/SiO2 (ONO) stacked gate dielectrics was investigated for the high speed dynamic random access memory (DRAM) and nonvolatile flash memory (NVM) operations. In the DRAM mode, clearly identified bi-stable current levels owing to the impact ionization effect were achieved as on- and off-states. In the NVM mode, a satisfactory memory window was obtained from the programming and the erasing operations by using the Fowler-Nordheim tunneling current. Additionally, the stable retention and endurance characteristics were achieved from the solid-phase crystallized poly-Si channel and the ONO stacked memory storage node.