Memory cell structure of semiconductor memory device
First Claim
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1. A memory cell employed in an erasable programmable read-only memory, comprising:
- a semiconductor substrate having a surface;
a source region formed on the substrate;
a channel region formed on the source region;
a drain region formed on the channel region;
a trench penetrating the drain region and the channel region, reaching the source region, and extending in a direction substantially perpendicular to the surface of the substrate the trench including an inner surface;
a floating gate comprising a first gate insulating layer formed on the inner surface of the trench, including an inner surface, and a first conductor formed in partial contact with the inside surface of the first gate insulating layer, and including a portion not in contact with the first gate insulating layer; and
a control gate comprising a second gate insulating layer formed on the portion of the first conductor which is not in contact with the first gate insulating layer, and a second conductor formed on the second gate insulating layer opposite to the portion in contact with the first conductor;
wherein a portion of the floating gate and a portion of the control gate project perpendicularly from the surface of the semiconductor substrate.
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Abstract
In a memory call of an EPROM, a drain region, a channel region, and a source region are formed in a direction perpendicular to the surface of a semiconductor substrate. A trench is provided, which penetrates the drain region and the channel region and reaches the source region. A floating gate and a control gate are formed in the trench, in a direction perpendicular to the surface of the semiconductor substrate.
36 Citations
4 Claims
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1. A memory cell employed in an erasable programmable read-only memory, comprising:
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a semiconductor substrate having a surface; a source region formed on the substrate; a channel region formed on the source region; a drain region formed on the channel region; a trench penetrating the drain region and the channel region, reaching the source region, and extending in a direction substantially perpendicular to the surface of the substrate the trench including an inner surface; a floating gate comprising a first gate insulating layer formed on the inner surface of the trench, including an inner surface, and a first conductor formed in partial contact with the inside surface of the first gate insulating layer, and including a portion not in contact with the first gate insulating layer; and a control gate comprising a second gate insulating layer formed on the portion of the first conductor which is not in contact with the first gate insulating layer, and a second conductor formed on the second gate insulating layer opposite to the portion in contact with the first conductor; wherein a portion of the floating gate and a portion of the control gate project perpendicularly from the surface of the semiconductor substrate. - View Dependent Claims (2, 3, 4)
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Specification