Method of fabricating a nonvolatile storage array with continuous control gate employing hot carrier injection programming
First Claim
1. A method of fabricating a storage device in an array of storage devices, comprising:
- forming first and second trenches in a semiconductor substrate, wherein;
the first trench and the second trench spaced-apart from one another;
each of the first trench and the second trench extends from a surface of the semiconductor substrate; and
a portion of the semiconductor substrate lies between and immediately adjacent to a first wall of the first trench and a second wall of the second trench;
forming first and second source/drain regions underlying the first and second trenches respectively;
forming a charge storage stack, wherein the charge storage stack lines the first and second trenches and overlies a portion of the semiconductor substrate between the first and second trenches, and wherein the charge storage stack includes a layer of discontinuous storage elements (DSEs); and
forming a first control gate overlying the first source/drain regions and the charge storage stack, wherein a set of the DSEs overlie the portion of the semiconductor substrate between the first and second trenches, and the set of DSEs lies between the first control gate and the portion of the semiconductor substrate; and
forming a first diffusion region between the first and second trenches, wherein;
the first diffusion region lies within the portion of the semiconductor substrate and at the surface of the semiconductor substrate; and
the first diffusion region is spaced apart from the first wall, the second wall, or both the first and second walls.
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Accused Products
Abstract
A method of making an array of storage cells includes a first source/drain region underlying a first trench defined in a semiconductor substrate and a second source/drain region underlying a second trench in the substrate. A charge storage stack lines each of the trenches where the charge storage stack includes a layer of discontinuous storage elements (DSEs). A control gate overlies the first trench. The control gate may run perpendicular to the trenches and traverse the first and second trenches. In another implementation, the control gate runs parallel with the trenches. The storage cell may include one or more diffusion regions occupying an upper surface of the substrate between the first and second trenches. The diffusion region may reside between first and second control gates that are parallel to the trenches. Alternatively, a pair of diffusion regions may occur on either side of a control gate that is perpendicular to the trenches.
73 Citations
20 Claims
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1. A method of fabricating a storage device in an array of storage devices, comprising:
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forming first and second trenches in a semiconductor substrate, wherein; the first trench and the second trench spaced-apart from one another; each of the first trench and the second trench extends from a surface of the semiconductor substrate; and a portion of the semiconductor substrate lies between and immediately adjacent to a first wall of the first trench and a second wall of the second trench; forming first and second source/drain regions underlying the first and second trenches respectively; forming a charge storage stack, wherein the charge storage stack lines the first and second trenches and overlies a portion of the semiconductor substrate between the first and second trenches, and wherein the charge storage stack includes a layer of discontinuous storage elements (DSEs); and forming a first control gate overlying the first source/drain regions and the charge storage stack, wherein a set of the DSEs overlie the portion of the semiconductor substrate between the first and second trenches, and the set of DSEs lies between the first control gate and the portion of the semiconductor substrate; and forming a first diffusion region between the first and second trenches, wherein; the first diffusion region lies within the portion of the semiconductor substrate and at the surface of the semiconductor substrate; and the first diffusion region is spaced apart from the first wall, the second wall, or both the first and second walls. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of fabricating a storage device in an array of storage devices, comprising:
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forming first and second trenches in a semiconductor substrate; forming first and second source/drain regions underlying the first and second trenches respectively; lining the first and second trenches with a charge storage stack, wherein the charge storage stack includes a layer of discontinuous storage elements (DSEs); forming a first control gate overlying the first source/drain regions; and forming a first diffusion region occupying an upper portion of the substrate between the first and second trenches wherein forming the first diffusion region is performed after lining the first and second trenches with the charge storage stack. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20)
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18. A method of fabricating a storage device, comprising:
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forming a first trench in a semiconductor substrate, wherein; the first trench has a first wall, wherein the first wall has a top and a bottom; and the semiconductor substrate has a surface at the top of the first wall; forming a first source/drain region underlying the first trench, wherein the first source/drain region has a first conductivity type; forming a gate dielectric layer along the first wall of the trench and the surface of the semiconductor substrate; forming a layer of discontinuous storage elements (DSEs) over the gate dielectric layer; and forming a first control gate overlying the first trench, wherein the first control gate overlies a set of DSEs, wherein the set of DSEs overlies the portion of the semiconductor substrate, wherein after forming the first control gate, substantially all of the portion of the semiconductor substrate that is immediately adjacent to the surface and directly below the first control gate has a second conductivity type that is opposite the first conductivity type.
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Specification