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US 5,633,821 AGranted
Nonvolatile memory device
AssigneeRohm Co., Ltd.
InventorsKiyoshi Nishimura, Hideki Hayashi, Jun Muramoto, Takaaki Fuchikami, Hiromi Uenoyama
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AssigneeRohm Co., Ltd.
InventorsKiyoshi Nishimura, Hideki Hayashi, Jun Muramoto, Takaaki Fuchikami, Hiromi Uenoyama
Estimating the term…
A nonvolatile memory with a simple structure where recorded information can be read without destruction. A voltage is impressed between a control gate and a memory gate for writing. A ferroelectric layer is polarized in accordance with the direction of the impressed voltage. A control gate voltage to make channel is small when the ferroelectric layer is polarized with the control gate side being positive. Control gate voltage to make channel is large when the ferroelectric layer is polarized with the control gate side being negative. The reference voltage is impressed on the control gate for reading. A large drain current flows when the ferroelectric layer is polarized with a second polarization and a small drain current flows when the ferroelectric layer is polarized with a first polarization. Record information can be read by detecting the drain current. Polarization status of the ferroelectric is not destroyed in the reading operation.
A nonvolatile memory device comprising:
A method for writing data into a nonvolatile memory device, said nonvolatile memory device comprising a source region of a first conductive type and a drain region of a first conductive type, a channel region of a second conductive type formed between the source and the drain regions, a memory gate formed on the channel region and insulated from the channel region, a predetermined voltage being applied to said memory gate in at least a write operation, a ferroelectric layer formed on the memory gate, a control gate formed on the ferroelectric layer, and a judgment circuit for a drain current connected to the drain region of the nonvolatile memory device, said method for writing data, said method comprising the steps of:
A method for reading out stored data from a nonvolatile memory device, said nonvolatile memory device comprising a source region of a first conductive type and a drain region of a first conductive type, a channel region of a second conductive type formed between the source and the drain regions, a memory gate formed on the channel region and insulated from the channel region, a predetermined voltage being applied to said memory gate in at least a write operation, a ferroelectric layer formed on the memory gate, a control gate formed on the ferroelectric layer, and a judgment circuit for a drain current connected to the drain region of the nonvolatile memory device, said method for writing data, said method comprising the steps of:
A method for writing to and reading from a nonvolatile memory device, said nonvolatile memory device comprising a source region of a first conductive type and a drain region of a first conductive type, a channel region of a second conductive type formed between the source and the drain regions, a memory gate formed on the channel region and insulated from the channel region, a predetermined voltage being applied to said memory gate in at least a operation, a ferroelectric layer formed on the memory gate, a control gate formed on the ferroelectric layer, and a judgment circuit for a drain current, connected to the drain region nonvolatile memory device, said method comprising a writing operation and a reading operation:
A method for writing data into a nonvolatile memory device, said nonvolatile memory device comprising a source region of a first conductive type and a drain region of a first conductive type, a channel region of a second conductive type formed between the source and the drain regions, a memory gate formed on the channel region and insulated from the channel region, a predetermined voltage being applied to said memory gate in at least a write operation, a ferroelectric layer formed on the memory gate, a control gate formed on the ferroelectric layer, and a judgment circuit for a drain current, connected to the drain region of the nonvolatile memory device, said method for writing data, said method comprising the steps of:
A method for reading out data from a nonvolatile memory device, said nonvolatile memory device comprising a source region of a first conductive type and a drain region of a first conductive type, a channel region of a second conductive type formed between the source and the drain regions, a memory gate formed on the channel region and insulated from the channel region, a predetermined voltage being applied to said memory gate in at least a write operation, a ferroelectric layer formed on the memory gate, a control gate formed on the ferroelectric layer, and a judgment circuit for a drain current, connected to the drain region of the nonvolatile memory device, said method for writing data, said method comprising the steps of:
A method for writing to and reading from a nonvolatile memory device, said nonvolatile memory device comprising a source region of a first conductive type and a drain region of a first conductive type, a channel region of a second conductive type formed between the source and the drain regions, a memory gate formed on the channel region and insulated from the channel region, a predetermined voltage being applied to said memory gate in at least a write operation, a ferroelectric layer formed on the memory gate, a control gate formed on the ferroelectric layer, and a judgment circuit for a drain current, connected to the drain region of the nonvolatile memory device, said method for writing data comprising a writing operation and a reading operation:
Dependencies are inferred from the claim text.