Programming nonvolatile memory device using program voltage with variable offset between programming state distributions
AssigneeSamsung Electronics Co., Ltd.
InventorsDong-Hun Kwak, Hyun-Wook Park, Hyun Jun Yoon, Doohyun Kim, Ki-Tae Park
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Abstract
A method of programming a nonvolatile memory device comprises applying at least one test program pulse to selected memory cells located in a scan read area, performing a scan read operation on the selected memory cells following application of the at least one test program pulse to detect at least one one-shot upper cell, calculating an offset voltage corresponding to a scan read region at which the scan read operation is performed, setting a program start bias using the offset voltage, and executing at least one program loop using the program start bias.
Claims20
A method of programming a nonvolatile memory device, the method comprising:
- applying at least one test program pulse to selected memory cells located in a scan read area of the nonvolatile memory device;
- performing a scan read operation on the selected memory cells, following the application of the at least one test program pulse, to determine a read operation voltage at which a predetermined number of one-shot upper cells are identified;
- calculating an offset voltage based on the difference between the determined read operation voltage and a reference voltage;
- setting a program start bias using the offset voltage;
- and
- executing at least one program loop using the program start bias,
- wherein the scan read operation comprises, increasing/decreasing the read operation voltage, performing another read operation, by applying the increased/decreased read operation voltage, iterating operations the increasing/decreasing and the performing another read operation until the number of off cells detected during the other read operation exceeds a predetermined number, and establishing the read operation voltage applied in the last iterations the increasing/decreasing and the performing another read operation as an offset index.
A method of programming a nonvolatile memory device, the method comprising:
- applying a test program pulse to memory cells to be programmed within a memory block;
- applying a test verification pulse to the memory cells to verify programming by the test program pulse;
- performing a scan read operation of the memory cells;
- changing an offset index in an offset index register according to a result of the scan read operation, the offset index stored at an offset index register according to a block address of the memory block comprising the memory cells;
- setting a program start bias using the offset index;
- and
- iterating program loops using the program start bias until a program operation is passed,
- wherein the scan read operation comprises:
- (a) performing a read operation, by applying a read operation voltage,
- (b) increasing/decreasing the read operation voltage,
- (c) performing another read operation, by applying the increased/decreased read operation voltage,
- (d) iterating operations (b) and (c) until the number of off cells detected during the other read operation exceeds a predetermined number, and
- (e) establishing the read operation voltage applied in the last iteration of operations (b) and (c) as the offset index.
A nonvolatile memory device, comprising:
- a controller configured to:
- apply at least one test program pulse to selected memory cells located in a scan read area of the nonvolatile memory device,
- perform a scan read operation on the selected memory cells, following the application of the at least one test program pulse, to determine a read operation voltage at which a predetermined number of one-shot upper cells are identified,
- calculate an offset voltage based on the difference between the determined read operation voltage and a reference voltage,
- set a program start bias using the offset voltage, and
- execute at least one program loop using the program start bias,
- wherein the scan read operation comprises, increasing/decreasing the read operation voltage, performing another read operation, by applying the increased/decreased read operation voltage, iterating operations the increasing/decreasing and the performing another read operation until the number of off cells detected during the other read operation exceeds a predetermined number, and establishing the read operation voltage applied in the last iterations the increasing/decreasing and the performing another read operation as an offset index.
Dependencies are inferred from the claim text.