THREE DIMENSIONAL NAND DEVICE WITH BIRDS BEAK CONTAINING FLOATING GATES AND METHOD OF MAKING THEREOF
First Claim
1. A method of making a monolithic three dimensional NAND string, comprising:
- forming a stack of alternating layers of a first material and a second material over a substrate, wherein the first material comprises an electrically insulating material and wherein the second material comprises a semiconductor or conductor material;
etching the stack to form a front side opening in the stack;
forming a blocking dielectric layer over the stack of alternating layers of a first material and a second material exposed in the front side opening;
forming a semiconductor or metal charge storage layer over the blocking dielectric;
forming a tunnel dielectric layer over the charge storage layer;
forming a semiconductor channel layer over the tunnel dielectric layer;
etching the stack to form a back side opening in the stack;
removing at least a portion of the first material layers and portions of the blocking dielectric layer through the back side opening to form back side recesses between the second material layers; and
oxidizing regions of the charge storage layer adjacent the back side recesses to form discrete charge storage regions.
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Accused Products
Abstract
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 over a substrate. The first material comprises an electrically insulating material and the second material comprises a semiconductor or conductor material. The method also includes etching the stack to form a front side opening in the stack, forming a blocking dielectric layer over the stack of alternating layers of a first material and a second material exposed in the front side opening, forming a semiconductor or metal charge storage layer over the blocking dielectric, forming a tunnel dielectric layer over the charge storage layer, forming a semiconductor channel layer over the tunnel dielectric layer, etching the stack to form a back side opening in the stack, removing at least a portion of the first material layers and portions of the blocking dielectric layer.
22 Citations
40 Claims
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1. A method of making a monolithic three dimensional NAND string, comprising:
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forming a stack of alternating layers of a first material and a second material over a substrate, wherein the first material comprises an electrically insulating material and wherein the second material comprises a semiconductor or conductor material; etching the stack to form a front side opening in the stack; forming a blocking dielectric layer over the stack of alternating layers of a first material and a second material exposed in the front side opening; forming a semiconductor or metal charge storage layer over the blocking dielectric; forming a tunnel dielectric layer over the charge storage layer; forming a semiconductor channel layer over the tunnel dielectric layer; etching the stack to form a back side opening in the stack; removing at least a portion of the first material layers and portions of the blocking dielectric layer through the back side opening to form back side recesses between the second material layers; and oxidizing regions of the charge storage layer adjacent the back side recesses to form discrete charge storage regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of making a monolithic three dimensional NAND string, comprising:
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forming a stack of alternating first and second layers over a substrate, wherein the first layers comprise an electrically insulating composite layer comprising a silicon nitride layer between silicon oxide layers and wherein the second layers comprise a semiconductor or conductor material; etching the stack to form a front side opening in the stack; forming a blocking dielectric layer over the stack of alternating first and second layers exposed in the front side opening; forming a charge storage layer over the layer of high work function material; forming a tunnel dielectric layer over the charge storage layer; forming a semiconductor channel layer over the tunnel dielectric layer; etching the stack to form a back side opening in the stack; removing at least a portion of the silicon nitride layer between silicon oxide layers to form back side recesses between adjacent second layers; removing portions of the blocking dielectric layer exposed in the back side recesses; and forming discrete charge storage regions. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A monolithic three dimensional NAND string, comprising:
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a semiconductor channel, at least one end portion 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; a blocking dielectric located in contact with the plurality of control gate electrodes; a plurality of vertically spaced apart charge storage regions located in contact with the blocking dielectric, wherein the plurality of vertically spaced apart charge storage regions comprise at least a first spaced apart charge storage region located in the first device level and a second spaced apart charge storage region located in the second device level and wherein a portion of the first and second charge storage regions comprises a bird'"'"'s beak shape; and a tunnel dielectric located between each one of the plurality of the vertically spaced apart charge storage regions and the semiconductor channel. - View Dependent Claims (31, 32, 33, 34, 35, 36)
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37. A method of making a monolithic three dimensional NAND string, comprising:
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forming a stack of alternating layers of a first material and a second material over a substrate, wherein the first material comprises an electrically insulating material and wherein the second material comprises a semiconductor or conductor material; etching the stack to form a front side opening in the stack; forming a blocking dielectric layer over the stack of alternating layers of a first material and a second material exposed in the front side opening; forming a charge storage layer over the blocking dielectric; forming a tunnel dielectric layer over the charge storage layer; forming a semiconductor channel layer over the tunnel dielectric layer; etching the stack to form a back side opening in the stack; removing at least a portion of the first material layers through the back side opening to form back side recesses between the second material layers; forming a protective layer on portions of the second material layers exposed in the back side recesses; after forming the protective layer, removing portions of the blocking dielectric layer exposed in the back side the recesses through the back side opening; and forming discrete charge storage regions. - View Dependent Claims (38, 39, 40)
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Specification