| 摘要 |
A nonvolatile semiconductor memory device. The nonvolatile semiconductor memory device includes a memory cell formed in a first well outputs a first voltage in response to a reference voltage necessary for program and erase verify operations. A reference cell formed in a second well generates a second voltage in response to the reference voltage in the program and erase verify operations. A comparator circuit compares the first voltage to the second voltage to detect whether the verify operation for the memory cell has passed, in the verify operation. A bias applying unit applies the same bias voltage to the first and second wells in the verify operation: Although there is an over-erased cell, an erase verify, operation can be correctly performed.
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