MEMORY SYSTEM
First Claim
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1. A memory system, comprising:
- nonvolatile memory cells each configured to store more than one bit of data;
dummy memory cells; and
a controller configured to control application of voltages to gates of the nonvolatile memory cells and the dummy memory cells, such that during an operation to read data from a group of the nonvolatile memory cells that are adjacent to the dummy memory cells, a read voltage is applied to the gates of the nonvolatile memory cells in the group while a first voltage is applied to gates of the dummy memory cells and a second voltage is applied to the other groups of the nonvolatile memory cells, the first voltage being higher than the second voltage.
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Abstract
A memory system includes nonvolatile memory cells each configured to store more than one bit of data, dummy memory cells adjacent to the nonvolatile memory cells, and a control section that applies a read voltage to the nonvolatile memory cells while a first voltage is applied to a gate of the dummy memory cells, when data of the nonvolatile memory cells are read out. The first voltage is higher than a second voltage for turning on the nonvolatile memory cells whose data are not read during the read out.
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Citations
20 Claims
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1. A memory system, comprising:
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nonvolatile memory cells each configured to store more than one bit of data; dummy memory cells; and a controller configured to control application of voltages to gates of the nonvolatile memory cells and the dummy memory cells, such that during an operation to read data from a group of the nonvolatile memory cells that are adjacent to the dummy memory cells, a read voltage is applied to the gates of the nonvolatile memory cells in the group while a first voltage is applied to gates of the dummy memory cells and a second voltage is applied to the other groups of the nonvolatile memory cells, the first voltage being higher than the second voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A memory system, comprising:
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multiple memory strings each including a plurality of nonvolatile memory cells connected serially between first and second selection transistors, each memory string including a dummy memory cell adjacent to the first selection transistor and each nonvolatile memory cell configured to store more than one bit of data; a plurality of word lines, each word line connected to a gate of a different memory cell in each of the memory strings, the word lines including a dummy word line connected to a gate of the dummy memory cell in each of the memory strings; and a controller configured to control application of voltages to the gates of the nonvolatile memory cells through the word lines, such that during an operation to read data from a group of the nonvolatile memory cells connected to a word line that is adjacent to the dummy word line, a read voltage is applied to the word line that is adjacent to the dummy word line while a first voltage is applied to the dummy word line, and a second voltage is applied to the other word lines, the first voltage being higher than the second voltage. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. In a memory system having multiple memory strings each including a plurality of nonvolatile memory cells connected serially between first and second selection transistors, each memory string including a dummy memory cell adjacent to the first selection transistor and each nonvolatile memory cell configured to store more than one bit of data, and a plurality of word lines, each word line connected to agate of a different memory cell in each of the memory strings, the word lines including a dummy word line connected to a gate of the dummy memory cell in each of the memory strings, a method of controlling voltages applied to the word lines during an operation to read data from a group of the nonvolatile memory cells connected to a word line that is adjacent to the dummy word line, comprising:
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applying a read voltage to the word line that is adjacent to the dummy word line while applying a first voltage to the dummy word line and a second voltage to the other word lines, wherein the first voltage is higher than the second voltage. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification