Non-volatile semiconductor memory with page erase
First Claim
1. A method for performing a page erase operation in a nonvolatile memory array havingplural strings of memory cells on a substrate, andplural wordlines across the strings to pages of memory cells;
- andassociated with plural pass transistors, each of which is configured to apply a voltage to a respective one of the wordlines,the memory array being divided into plural blocks, the method comprising;
selecting at least one of the blocks;
selecting any one or ones of the wordlines of the selected block;
enabling each of the pass transistors associated with the selected block;
applying a select voltage to the selected one or ones of the wordlines of the selected block;
applying an unselect voltage to unselected one or ones of the wordlines that are other than the selected one or ones of the wordlines of the selected block; and
applying a substrate voltage to the substrate of the selected block,the voltage difference between the substrate voltage and the select voltage causing the page or pages of memory cells coupled to the selected one or ones of the wordlines to be erased, andthe voltage difference between the substrate voltage and the unselect voltage not causing the page or pages of memory cells coupled to the unselected one or ones of the wordlines of the selected block to be erased.
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Abstract
In a nonvolatile memory, less than a full block maybe erased as one or more pages. A select voltage is applied through pass transistors to each of plural selected wordlines and an unselect voltage is applied through pass transistor to each of plural unselected wordlines of a selected block. A substrate voltage is applied to the substrate of the selected block. A common select voltage may be applied to each selected wordline and the common unselect voltage may be applied to each unselected wordline. Select and unselect voltages may be applied to any of the wordlines of a select block. A page erase verify operation may be applied to a block having plural erased pages and plural nonerased pages.
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Citations
18 Claims
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1. A method for performing a page erase operation in a nonvolatile memory array having
plural strings of memory cells on a substrate, and plural wordlines across the strings to pages of memory cells; - and
associated with plural pass transistors, each of which is configured to apply a voltage to a respective one of the wordlines, the memory array being divided into plural blocks, the method comprising; selecting at least one of the blocks; selecting any one or ones of the wordlines of the selected block; enabling each of the pass transistors associated with the selected block; applying a select voltage to the selected one or ones of the wordlines of the selected block; applying an unselect voltage to unselected one or ones of the wordlines that are other than the selected one or ones of the wordlines of the selected block; and applying a substrate voltage to the substrate of the selected block, the voltage difference between the substrate voltage and the select voltage causing the page or pages of memory cells coupled to the selected one or ones of the wordlines to be erased, and the voltage difference between the substrate voltage and the unselect voltage not causing the page or pages of memory cells coupled to the unselected one or ones of the wordlines of the selected block to be erased. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A nonvolatile memory comprising:
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a memory array comprising plural strings of memory cells on a substrate and plural wordlines across the strings to pages of memory cells, the memory array being divided into plural blocks; plural pass transistors, each of which is configured to apply a voltage to a respective one of the wordlines; a block selector for selecting at least one of the blocks to enable each of the pass transistors in the selected block during an erase operation; a substrate voltage source for applying a substrate voltage to the substrate during the erase operation; and a wordline decoder for selecting any one or ones of the wordlines of the selected block to apply a select voltage to the selected one or ones of the wordlines to erase one or ones of the pages of memory cells coupled to the selected one or ones of the wordlines of the selected block and an unselect voltage to unselected one or ones of the wordlines that are other than the selected one or ones of the wordlines of the selected block, the wordline decoder being configured to respond to address instructions to apply the select voltage to the selected one or ones of the wordlines of the selected block and to apply the unselect voltage to the unselected one or ones of the wordlines of the selected block. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification