Novel High Density 3D Buffer Memory Enabled by IGZO Channel Charge Coupled Device

Abstract

We propose a novel 3D Charge Coupled Device (CCD) for high density block addressable buffer memory with IGZO channel and integrable in 3D NAND Flash string architecture. To this purpose, we demonstrate the memory operation using IGZO-based planar 4-phase CCD structure with 142-bits. The devices have charge transfer efficiency > 98%, retention > 200 s, endurance > 1010 cycles without any degradation, with charge transfer speed > 6.25 MHz. Multibit storage is possible, enabling bit densities surpassing the projected DRAM bit density with only ~50 layers.