Method of making a three dimensional NAND device
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 different from the first material over a substrate, the first material layers comprising a sacrificial material and the second material layers comprising an electrically insulating material;
forming at least one front side opening in the stack;
forming a charge storage material layer in the at least one front side opening;
forming a tunnel dielectric over the charge storage material layer in the at least one front side opening;
forming a semiconductor channel over the tunnel dielectric in the at least one front side opening;
forming a back side opening in the stack;
selectively removing the first material layers without removing the second material layers through the back side opening, thereby forming back side recesses between adjacent second material layers, wherein the portions of the charge storage material layer on exposed in the back side recesses;
selectively oxidizing portions of the charge storage material layer exposed in the back side recesses partially through a thickness of the charge storage material layer to form a cover oxide segments in the charge storage material layer;
forming a blocking dielectric over a sidewall in the back side opening, over exposed surfaces of the second material layers and over the cover oxide segments in the back side recesses, the blocking dielectric having a clam-shaped portion in the back side recesses; and
forming a plurality of control gate electrodes, each of the plurality of control gate electrodes is located at least partially in an opening in the respective clam-shaped portion of the blocking dielectric.
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Accused Products
Abstract
A monolithic three dimensional NAND string includes a semiconductor channel, an 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, a charge storage material layer located between the plurality of control gate electrodes and the semiconductor channel, a tunnel dielectric located between the charge storage material layer and the semiconductor channel, and a blocking dielectric containing a plurality of clam-shaped portions each having two horizontal portions connected by a vertical portion. Each of the plurality of control gate electrodes are located at least partially in an opening in the clam-shaped blocking dielectric, and a plurality of discrete cover oxide segments embedded in part of a thickness of the charge storage material layer and located between the blocking dielectric and the charge storage material layer.
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Citations
11 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 different from the first material over a substrate, the first material layers comprising a sacrificial material and the second material layers comprising an electrically insulating material; forming at least one front side opening in the stack; forming a charge storage material layer in the at least one front side opening; forming a tunnel dielectric over the charge storage material layer in the at least one front side opening; forming a semiconductor channel over the tunnel dielectric in the at least one front side opening; forming a back side opening in the stack; selectively removing the first material layers without removing the second material layers through the back side opening, thereby forming back side recesses between adjacent second material layers, wherein the portions of the charge storage material layer on exposed in the back side recesses; selectively oxidizing portions of the charge storage material layer exposed in the back side recesses partially through a thickness of the charge storage material layer to form a cover oxide segments in the charge storage material layer; forming a blocking dielectric over a sidewall in the back side opening, over exposed surfaces of the second material layers and over the cover oxide segments in the back side recesses, the blocking dielectric having a clam-shaped portion in the back side recesses; and forming a plurality of control gate electrodes, each of the plurality of control gate electrodes is located at least partially in an opening in the respective clam-shaped portion of the blocking dielectric. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification