Scaling Trends in NAND Flash

As the 2D NAND Flash scaling plateaued due to physical and electrical scaling limitations, 3D NAND emerged as a strong successor to continue the scaling trend. 3D NAND has rapidly achieved maturity and is already in the 3 ^rd and 4 ^th generation of technology with the total number of layers reaching 96 active layers. The improved cell characteristics of 3D NAND have enabled 4bits/cell capability, allowing for further bit density scaling. This paper describes some of the recent innovations in the 3D NAND technology and the key challenges ahead for continued scaling.