FLOATING GATE ULTRAHIGH DENSITY VERTICAL NAND FLASH MEMORY AND METHOD OF MAKING THEREOF

摘要

A method of making a monolithic three dimensional NAND string including providing a stack of alternating first material layers and second material layers over a substrate. The first material layers comprise an insulating material and the second material layers comprise sacrificial layers. The method also includes forming a back side opening in the stack, selectively removing the second material layers through the back side opening to form back side recesses between adjacent first material layers and forming a blocking dielectric (7) inside the back side recesses and the back side opening. The blocking dielectric (7) has a clam shaped regions inside the back side recesses. The method also includes forming a plurality of copper control gate electrodes (3) in the respective clam shell shaped regions of the blocking dielectric in the back side recesses.