Semiconductor nonvolatile memory
First Claim
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1. A semiconductor nonvolatile memory comprising:
- a semiconductor substrate of a first conductivity type having a stepped portion having a top face section and a bottom face section separated from one another by a side face section;
a source region of a second conductivity type provided in the top face section of the stepped portion;
a drain region of the second conductivity type provided in the bottom face section of the stepped portion;
a first channel region adjacent to the source region and formed in the side face section and in a part of the bottom face section of the stepped portion;
a second channel region formed between the first channel region and the drain region in the bottom face section of the stepped portion;
a control gate electrode formed over the first channel region and the source region through a gate insulating film for controlling the first channel region conductance; and
a floating gate electrode formed over the second channel region through a gate insulating film for controlling the second channel region conductance.
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Abstract
The invention is directed to a semiconductor nonvolatile memory of the floating gate type having dual gate structure comprised of a first channel region having a channel resistance controlled by a control gate electrode and a second channel region having a channel resistance controlled by a floating gate electrode. The first channel region is formed on one face section of semiconductor substrate which has a crystal face orientation different from that of another face section on which the second channel region is formed. By such construction, channel length of the first and second channel regions can be shortened to increase memory capacity density and to improve quality.
37 Citations
16 Claims
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1. A semiconductor nonvolatile memory comprising:
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a semiconductor substrate of a first conductivity type having a stepped portion having a top face section and a bottom face section separated from one another by a side face section; a source region of a second conductivity type provided in the top face section of the stepped portion; a drain region of the second conductivity type provided in the bottom face section of the stepped portion; a first channel region adjacent to the source region and formed in the side face section and in a part of the bottom face section of the stepped portion; a second channel region formed between the first channel region and the drain region in the bottom face section of the stepped portion; a control gate electrode formed over the first channel region and the source region through a gate insulating film for controlling the first channel region conductance; and a floating gate electrode formed over the second channel region through a gate insulating film for controlling the second channel region conductance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A semiconductor nonvolatile memory comprising:
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a semiconductor substrate of a first conductivity type having a stepped portion having a top face section and a bottom face section separated from one another by a side face section; a source region of a second conductivity type provided in the bottom face section of the stepped portion; a drain region of the second conductivity type provided in the top face section of the stepped portion; a first channel region adjacent to the source region and formed in the bottom face section of the stepped portion; a second channel region formed between the drain region and the first channel region in the side face section and in a part of the bottom face section of the stepped portion; a control gate electrode formed over the first channel region and the source region through a gate insulating film for controlling the first channel region conductance; and a floating gate electrode formed over the second channel region through a gate insulating film for controlling the second channel region conductance. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification