NON-VOLATILE SEMICONDUCTOR MEMORY AND SEMICONDUCTOR INTEGRATED CIRCUIT HAVING BUILT-IN NON-VOLATILE SEMICONDUCTOR MEMORY

摘要

PROBLEM TO BE SOLVED: To shorten a write time required by decreasing the total number of write by deciding the completion of write by read at voltage, where the conditions of verification are relaxed in response to the number of the application of write voltage to the same storage element. ;SOLUTION: A circuit capable of generating verify voltage set at a slightly high level while imparting an allowance value to verify voltage at a preset specified level besides the verify voltage at the preset specified level as write verify voltage applied to a word line and a circuit capable of changing over these voltage are mounted on a flash memory. A counter counting the number of the application of write pulses is prepared in a memory for operation. A maximally small value within a range that a malfunction by the noises of a sense amplifier can be avoided is used as the allowance value of verify voltage. Verify voltage after the application of the odd number of write pulses is made higher than that after the application of the even number of write pulses.;COPYRIGHT: (C)2000,JPO