TCAD Simulation of a 3D NAND Memory Utilizing In-Ga-Zn-Oxide: "3D OS NAND" with 4 V Drive, High Endurance and Density

Abstract

We have evaluated, through TCAD simulation, 3-dimensional oxide-semiconductor NAND (3D OS NAND), a novel vertically-stacked 2T-1C memory using cylindrical c-axis aligned crystalline In-Ga-Zn-Oxide (CAAC-IGZO) channels. Taking advantage of low off-leakage of CAAC-IGZO field-effect transistors (CAAC-IGZO FETs), the memory does not use a metal-oxide-nitride-oxide-silicon (MONOS) structure for writing. This memory architecture is potentially capable of achieving a memory density and a 10-year retention similar to NAND flash, operating with a supply voltage of 4 V or below, while overcoming the endurance challenge of NAND flash.