NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE
First Claim
Patent Images
1. A non-volatile semiconductor memory device comprising:
- a cross-point cell array;
a plurality of word lines extended in a first direction;
a plurality of bit lines extended in a second direction different from the first direction;
a first decoding circuit for selecting a selected word line from the plurality of word lines;
a second decoding circuit for selecting a selected bit line from the plurality of bit lines;
a first reference signal generating circuit for generating a first reference signal;
a second reference signal generating circuit for generating a second reference signal different from the first reference signal; and
a read circuit,wherein the cross-point cell array includes a plurality of cells,each of the plurality of cells is interposed between one of the plurality of word lines and one of the plurality of bit lines,a selected cell is interposed between the selected word line and the selected bit line,based on a detection signal corresponding to a detection current which is caused to flow through the selected bit line by applying a voltage between the selected word line and the selected bit line, the read circuit compares a first difference signal corresponding to a difference between the detection signal and the first reference signal with a second difference signal corresponding to a difference between the detection signal and the second reference signal, thereby determining data stored in the selected cell.
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Abstract
In order to determine data stored in a memory cell of a resistive cross-point cell array, two reference cells having two different known resistance values (e.g., data “0” and data “1”) are provided, and a difference in current between a selected cell and the reference cell having data “0” and a difference in current between the selected cell and the reference cell having data “1” are compared. By comparison with a current of the reference cell which has a parasitic current as with the selected cell and has known data “0”/“1”, data can be determined while suppressing an influence of a parasitic current.
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Citations
19 Claims
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1. A non-volatile semiconductor memory device comprising:
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a cross-point cell array; a plurality of word lines extended in a first direction; a plurality of bit lines extended in a second direction different from the first direction; a first decoding circuit for selecting a selected word line from the plurality of word lines; a second decoding circuit for selecting a selected bit line from the plurality of bit lines; a first reference signal generating circuit for generating a first reference signal; a second reference signal generating circuit for generating a second reference signal different from the first reference signal; and a read circuit, wherein the cross-point cell array includes a plurality of cells, each of the plurality of cells is interposed between one of the plurality of word lines and one of the plurality of bit lines, a selected cell is interposed between the selected word line and the selected bit line, based on a detection signal corresponding to a detection current which is caused to flow through the selected bit line by applying a voltage between the selected word line and the selected bit line, the read circuit compares a first difference signal corresponding to a difference between the detection signal and the first reference signal with a second difference signal corresponding to a difference between the detection signal and the second reference signal, thereby determining data stored in the selected cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A non-volatile semiconductor memory device comprising:
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a cross-point cell array; a plurality of word lines extended in a first direction; a plurality of bit lines extended in a second direction different from the first direction; a first decoding circuit for selecting a selected word line from the plurality of word lines; a second decoding circuit for selecting a selected bit line from the plurality of bit lines; a first reference signal generating circuit for generating a first reference signal; a second reference signal generating circuit for generating a second reference signal different from the first reference signal; and a read circuit for determining data stored in a selected cell based on a detection signal corresponding to a detection current flowing through the selected bit line, wherein the read circuit includes; a difference signal generating circuit for generating a difference signal corresponding to a difference between two different signals; and a reference signal selecting circuit for connecting the first reference signal generating circuit to the difference signal generating circuit during a first read operation period, and connecting the second reference signal generating circuit to the difference signal generating circuit during a second read operation period delayed in time from the first read operation period, and the read circuit connects the selected bit line via the second decoding circuit to the difference signal generating circuit and the first reference signal generating circuit to the difference signal generating circuit during the first read operation period, and connects the selected bit line via the second decoding circuit to the difference signal generating circuit and the second reference signal generating circuit to the difference signal generating circuit during the second read operation period. - View Dependent Claims (18)
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19. A non-volatile semiconductor memory device comprising:
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a cross-point cell array; a plurality of word lines extended in a first direction; a plurality of bit lines extended in a second direction different from the first direction; a first decoding circuit for selecting a selected word line from the plurality of word lines; a second decoding circuit for selecting a selected bit line from the plurality of bit lines; a first reference signal generating circuit for generating a first reference signal; a second reference signal generating circuit for generating a second reference signal different from the first reference signal; and a read circuit for determining data stored in a selected cell based on a detection signal corresponding to a detection current flowing through the selected bit line, wherein the read circuit includes; a first difference signal generating circuit for generating a first difference signal corresponding to a difference between the detection signal and the first reference signal; and a second difference signal generating circuit for generating a second difference signal corresponding to a difference between the detection signal and the second reference signal, and the read circuit connects the selected bit line via the second decoding circuit to the first difference signal generating circuit and the first reference signal generating circuit to the first difference signal generating circuit, and connects the selected bit line via the second decoding circuit to the second difference signal generating circuit and the second reference signal generating circuit to the second difference signal generating circuit.
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Specification