LOW VOLTAGE PROGRAMMING IN NAND FLASH
First Claim
1. A memory comprising:
- a plurality of memory cells arranged in series in a semiconductor body;
a plurality of word lines, word lines in the plurality coupled to corresponding memory cells in the plurality of memory cells; and
control circuitry coupled to the plurality of word lines adapted for programming a selected memory cell in the plurality of memory cells corresponding to a selected word line by;
biasing one of first and second ends of the plurality of memory cells to a drain side voltage, and another of the first and second ends to a source side voltage during the program interval,applying drain-side pass voltages to word lines between the selected word line and said one of first and second ends during a program interval,applying source-side pass voltages to word lines between the selected word line and said other of first and second ends during a program interval,applying a program voltage to the selected word line during the program interval, andapplying a switching voltage to a word line and corresponding memory cell adjacent the selected word line and selected memory cell to control conductance during the program interval.
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Accused Products
Abstract
A memory device includes a plurality of memory cells arranged in series in the semiconductor body, such as a NAND string, having a plurality of word lines. A selected memory cell is programmed by hot carrier injection. The program operation is based on metering a flow of carriers between a first semiconductor body region on a first side of the selected cell in the NAND string and a second semiconductor body region on a second side of the selected cell. A program potential higher than a hot carrier injection barrier level is applied to the selected cell, and then the drain to source voltage across the selected cell and the flow of carriers in the selected cell reach a level sufficient to support hot carrier injection, which is controlled by a switch cell adjacent the selected cell.
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Citations
25 Claims
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1. A memory comprising:
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a plurality of memory cells arranged in series in a semiconductor body; a plurality of word lines, word lines in the plurality coupled to corresponding memory cells in the plurality of memory cells; and control circuitry coupled to the plurality of word lines adapted for programming a selected memory cell in the plurality of memory cells corresponding to a selected word line by; biasing one of first and second ends of the plurality of memory cells to a drain side voltage, and another of the first and second ends to a source side voltage during the program interval, applying drain-side pass voltages to word lines between the selected word line and said one of first and second ends during a program interval, applying source-side pass voltages to word lines between the selected word line and said other of first and second ends during a program interval, applying a program voltage to the selected word line during the program interval, and applying a switching voltage to a word line and corresponding memory cell adjacent the selected word line and selected memory cell to control conductance during the program interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A memory comprising:
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a NAND string including a plurality of memory cells arranged in series in a semiconductor body; a plurality of word lines, word lines in the plurality coupled to corresponding memory cells in the plurality of memory cells; and control circuitry coupled to the plurality of word lines adapted for programming a selected memory cell in the plurality of memory cells corresponding to a selected word line by; controlling conductance in the NAND string by applying a switching voltage to a word line adjacent the selected word line to induce an effective source in a first semiconductor body region on one side of a selected cell and to induce an effective drain in a second semiconductor body region on another side of the selected cell in the NAND string; biasing the first semiconductor body region to a source side voltage; biasing the second semiconductor body region to a drain side voltage; and applying a program potential greater than a hot carrier injection barrier level to the selected cell.
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21. A method for inducing hot carrier injection in a selected cell in a NAND string in a NAND array, comprising:
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controlling conductance in the NAND string by applying a switching voltage to a word line adjacent the selected word line to induce an effective source on a first side of a selected cell and to induce an effective drain on a second side of the selected cell in the NAND string; biasing the effective drain to a drain side voltage; biasing the effective source to a source side reference voltage; applying a program potential greater than a hot carrier injection barrier level to the selected cell. - View Dependent Claims (22, 23, 24, 25)
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Specification