THREE DIMENSIONAL NAND DEVICE WITH SILICON GERMANIUM HETEROSTRUCTURE CHANNEL

摘要

A method of making a monolithic three dimensional NAND string including forming a stack of alternating layers of a first material and a second material different from the first material over a substrate, forming an at least one opening in the stack, forming at least a portion of a memory film in the at least one opening and forming a first portion of a semiconductor channel followed by forming a second portion of the semiconductor channel in the at least one opening. The second portion of the semiconductor channel comprises silicon and germanium and contains more germanium than a first portion of the semiconductor channel which is located closer to the memory film than the second portion.

主权项

1. A monolithic three dimensional NAND string, comprising:
a semiconductor channel, at least one end part of the semiconductor channel extending substantially perpendicular to a major surface of a substrate; a plurality of control gate electrodes 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 major surface of the substrate and below the first device level, wherein the first control gate electrode is separated from the second control gate electrode by an insulating layer located between the first and second control gates; a blocking dielectric located adjacent the plurality of control gate electrodes; at least one charge storage region located adjacent the blocking dielectric; and a tunnel dielectric located between the at least one charge storage region and the semiconductor channel, wherein a second portion of the semiconductor channel comprises silicon and germanium and contains more germanium than a first portion of the semiconductor channel which is located closer to the tunnel dielectric than the second portion.