Non-volatile dynamic random access memory
First Claim
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1. A memory cell comprising:
- an MOS transistor having a first current carrying terminal coupled to a first node, a second current carrying terminal coupled to a bitline associated with the memory cell, and a gate terminal coupled to a first terminal of the memory cell; and
a non-volatile device comprising;
a substrate region coupled to a second terminal of the memory;
a source region formed in the substrate region and coupled to the first node;
a drain region formed in the substrate region and separated from the source region by a first channel region;
said drain region being coupled to a third terminal of the memory cell;
a first gate overlaying a first portion of the first channel region and separated therefrom via a first insulating layer;
said first gate coupled to a fourth terminal of the memory cell; and
a second gate overlaying a second portion of the first channel region and separated therefrom via a second insulating layer;
wherein said first portion of the first channel region and said second portion of the channel do not overlap and wherein said second gate is coupled to a fifth terminal of the memory cell.
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Abstract
In accordance with the present invention, a memory cell includes a non-volatile device and a DRAM cell. The DRAM cell further includes an MOS transistor and a capacitor. The non-volatile device include a control gate region and a guiding gate region that may partially overlap. The non-volatile device is erased prior to being programmed. Programming of the non-volatile device may be done via hot-electron injection or Fowler-Nordheim tunneling. When a power failure occurs, the data stored in the DRAM is loaded in the non-volatile devices. After the power is restored, the data stored in the non-volatile device is restored in the DRAM cell.
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16 Claims
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1. A memory cell comprising:
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an MOS transistor having a first current carrying terminal coupled to a first node, a second current carrying terminal coupled to a bitline associated with the memory cell, and a gate terminal coupled to a first terminal of the memory cell; and
a non-volatile device comprising;
a substrate region coupled to a second terminal of the memory;
a source region formed in the substrate region and coupled to the first node;
a drain region formed in the substrate region and separated from the source region by a first channel region;
said drain region being coupled to a third terminal of the memory cell;
a first gate overlaying a first portion of the first channel region and separated therefrom via a first insulating layer;
said first gate coupled to a fourth terminal of the memory cell; and
a second gate overlaying a second portion of the first channel region and separated therefrom via a second insulating layer;
wherein said first portion of the first channel region and said second portion of the channel do not overlap and wherein said second gate is coupled to a fifth terminal of the memory cell.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification