Patent ID: 8450791

Claim:
A monolithic three dimensional NAND string, comprising: a semiconductor channel located over a substrate, at least one end of the semiconductor channel extending substantially perpendicular to a major surface of the substrate; a plurality of control gate electrodes having a strip shape extending substantially parallel to the major surface of the substrate, wherein the plurality of control gate electrodes comprise at least a first control gate electrode located in a first device level and a second control gate electrode located in a second device level located over the substrate and below the first device level; a plurality of discrete charge storage segments, wherein the plurality of discrete charge storage segments comprise at least a first discrete charge storage segment located in the first device level and a second discrete charge storage segment located in the second device level; a blocking dielectric located between the plurality of discrete charge storage segments and the plurality of control gate electrodes; and a tunneling dielectric located between the plurality of discrete charge storage segments and the semiconductor channel; wherein the first discrete charge storage segment has a height shorter than that of the first control gate electrode and the second discrete charge storage segment has a height shorter than that of the second control gate electrode; and wherein the tunnel dielectric has a straight sidewall throughout the first and the second device levels.