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US 7,257,026 B2Granted
Non-volatile multi-level semiconductor flash memory device and method of driving same
AssigneeElpida Memory, Inc.
InventorsNaoki Yamada, Hiroshi Sato, Tetsuya Tsujikawa, Kazuyuki Miyazawa
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Abstract
In a nonvolatile semiconductor memory device in which a plurality of threshold values are set to store multi-level data in a memory cell, bits of multi-bit data are separately written into a memory cell according to an address signal or a control signal to effect the reading and erasing. Concretely, the memory array is so constituted that it can be accessed by three-dimensional address of X, Y and Z, and multi-bit data in the memory cell is discriminated by the Z-address.
Claims4
A nonvolatile memory comprising:
- a plurality of memory cells,
- a plurality of word lines, each of which couples to corresponding ones of said memory cells,
- wherein said nonvolatile memory is capable of receiving a plurality of commands which include a read command accompanied with a read address and a discriminating address discriminating bits in the memory cells,
- wherein said nonvolatile memory is adapted to perform either a first read operation or a second read operation according to the discriminating address,
- wherein, in the first read operation, the nonvolatile memory is adapted to output the data by selecting one of the plurality of word lines once, and
- wherein, in the second read operation, the nonvolatile memory is adapted to output the data by selecting one of the plurality of word lines twice.
3 more elements
Dependencies are inferred from the claim text.