Nonvolatile memory, verify method therefor, and semiconductor device using the nonvolatile memory
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorKiyoshi Kato
Life of this patent
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Abstract
Provided is a nonvolatile memory that realizes a high-speed verify operation. During verify writing/erasing, the writing/erasing and reading are performed at the same time. As to a circuit that performs a verify operation, for instance, there is obtained a construction where the output from a sense amplifier (102) that performs reading is connected to a switch which switches an operation voltage applied to a memory cell in accordance with a verify signal Sv, and the verify operation is finished concurrently with having the verify signal Sv switched. By obtaining such circuit construction and simultaneously performing writing/erasing and reading, it becomes possible to perform high-speed verify writing/erasing.
Claims113
A driving method of a nonvolatile memory,
- wherein during a verify operation, a first operation for changing a threshold voltage of the memory element is performed concurrently with a second operation for judging the threshold voltage of the memory element.
A driving method of a nonvolatile memory,
- wherein during a verify operation, a first operation for changing a threshold voltage of the memory element by one of charge injection and charge discharge using a tunnel current is performed concurrently with a second operation for judging the threshold voltage of the memory element.
A driving method of a nonvolatile memory,
- wherein during a verify operation, a first operation for changing a threshold voltage of the memory element by charge injection using a hot electron is performed concurrently with a second operation for judging the threshold voltage of the memory element.
A driving method of a nonvolatile memory for setting a threshold voltage of the memory element at a set voltage or higher,
- wherein during a verify operation, a first operation for increasing the threshold voltage of the memory element is performed concurrently with a second operation for judging a relation between the threshold voltage of the memory element and the set voltage,
- wherein a result of the second operation is outputted as a verify signal,
- wherein the verify signal takes a first value if the threshold voltage of the memory element is smaller than the set voltage, and takes a second value if the threshold voltage of the memory element is larger than the set voltage,
- wherein the first operation is performed if the verify signal takes the first value, and is not performed if the verify signal takes the second value, and
- wherein the first operation and the second operation are terminated and the verify operation is finished when the verify signal changes from the first value to the second value.
A driving method of a nonvolatile memory driving for setting a threshold voltage of the memory element at a set voltage or lower,
- wherein during a verify operation, a first operation for decreasing the threshold voltage of the memory element is performed concurrently with a second operation for judging a relation between the threshold voltage of the memory element and the set voltage,
- wherein a result of the second operation is outputted as a verify signal,
- wherein the verify signal takes a first value if the threshold voltage of the memory element is larger than the set voltage, and takes a second value if the threshold voltage of the memory element is smaller than the set voltage,
- wherein the first operation is performed if the verify signal takes the first value, and is not performed if the verify signal takes the second value, and
- wherein the first operation and the second operation are terminated and the verify operation is finished when the verify signal changes from the first value to the second value.
A driving method of a nonvolatile memory for setting a threshold voltage of a memory element at a set voltage or higher,
- wherein during a verify operation, a first operation for increasing the threshold voltage of the memory element is performed concurrently with a second operation for judging a relation between the threshold voltage of the memory element and the set voltage,
- wherein the verify operation includes at least a first period and a second period,
- wherein a verify signal takes a first value during the first period,
- wherein a result of the second operation is outputted as the verify signal during the second period,
- wherein during the second period, the verify signal takes the first value if the threshold voltage of the memory element is smaller than the set voltage, and takes a second value if the threshold voltage of the memory element is larger than the set voltage,
- wherein the first operation is performed if the verify signal takes the first value, and is not performed if the verify signal takes the second value, and
- wherein the first operation and the second operation are terminated and the verify operation is finished when the verify signal changes from the first value to the second value.
A driving method of a nonvolatile memory for setting a threshold voltage of a memory element at a set voltage or lower,
- wherein during a verify operation, a first operation for decreasing the threshold voltage of the memory element is performed concurrently with a second operation for judging a relation between the threshold voltage of the memory element and the set voltage,
- wherein the verify operation includes at least a first period and a second period,
- wherein a verify signal takes a first value during the first period,
- wherein a result of the second operation is outputted as the verify signal during the second period,
- wherein during the second period, the verify signal takes the first value if the threshold voltage of the memory element is larger than the set voltage, and takes a second value if the threshold voltage of the memory element is smaller than the set voltage,
- wherein the first operation is performed if the verify signal takes the first value, and is not performed if the verify signal takes the second value, and
- wherein the first operation and the second operation are terminated and the verify operation is finished when the verify signal changes from the first value to the second value.
A nonvolatile memory that performs a verify operation, comprising:
- a means for simultaneously performing a first operation for changing a threshold voltage of a memory element and a second operation for judging the threshold voltage of the memory element.
A nonvolatile memory that performs a verify operation, comprising:
- a means for simultaneously performing a first operation for changing a threshold voltage of a memory element by one of charge injection and charge discharge using a tunnel current and a second operation for judging the threshold voltage of the memory element.
A nonvolatile memory that performs a verify operation, comprising:
- a means for simultaneously performing a first operation for changing a threshold voltage of a memory element by charge injection using a hot electron and a second operation for judging the threshold voltage of the memory element.
A nonvolatile memory that performs a verify operation for setting a threshold voltage of a memory element at a set voltage or higher, the nonvolatile memory comprising:
- a means for simultaneously performing a first operation for increasing the threshold voltage of the memory element and a second operation for judging a relation between the threshold voltage of the memory element and the set voltage;
- a means for, during the second operation, generating a verify signal that takes a first value if the threshold voltage of the memory element is smaller than the set voltage and takes a second value if the threshold voltage of the memory element is larger than the set voltage;
- a means for performing the first operation if the verify signal takes the first value, and not performing the first operation if the verify signal takes the second value;
- and
- a means for terminating the first operation and the second operation and finishing the verify operation when the verify signal changes from the first value to the second value.
A nonvolatile memory that performs a verify operation for setting a threshold voltage of a memory element at a set voltage or lower, the nonvolatile memory comprising:
- a means for simultaneously performing a first operation for decreasing the threshold voltage of the memory element and a second operation for judging a relation between the threshold voltage of the memory element and the set voltage;
- a means for, during the second operation, generating a verify signal that takes a first value if the threshold voltage of the memory element is larger than the set voltage and takes a second value if the threshold voltage of the memory element is smaller than the set voltage;
- a means for performing the first operation if the verify signal takes the first value, and not performing the first operation if the verify signal takes the second value;
- and
- a means for terminating the first operation and the second operation and finishing the verify operation when the verify signal changes from the first value to the second value.
A nonvolatile memory that performs a verify operation for setting a threshold voltage of a memory element at a set voltage or higher, the nonvolatile memory comprising:
- a means for simultaneously performing a first operation for increasing the threshold voltage of the memory element and a second operation for judging a relation between the threshold voltage of the memory element and the set voltage;
- a means for generating a verify signal that takes a first value during a first period;
- a means for, during a second period, generating a verify signal that takes the first value if the threshold voltage of the memory element is smaller than the set voltage, and takes a second value if the threshold voltage of the memory element is larger than the set voltage;
- a means for performing the first operation if the verify signal takes the first value, and not performing the first operation if the verify signal takes the second value;
- and
- a means for terminating the first operation and the second operation and finishing the verify operation when the verify signal changes from the first value to the second value.
A nonvolatile memory that performs a verify operation for setting a threshold voltage of a memory element at a set voltage or lower, the nonvolatile memory comprising:
- a means for simultaneously performing a first operation for decreasing the threshold voltage of the memory element and a second operation for judging a relation between the threshold voltage of the memory element and the set voltage;
- a means for generating a verify signal that takes a first value during a first period;
- a means for, during a second period, generating a verify signal that takes the first value if the threshold voltage of the memory element is larger than the set voltage, and takes a second value if the threshold voltage of the memory element is smaller than the set voltage;
- a means for performing the first operation if the verify signal takes the first value, and not performing the first operation if the verify signal takes the second value;
- and
- a means for terminating the first operation and the second operation and finishing the verify operation when the verify signal changes from the first value to the second value.
Dependencies are inferred from the claim text.