| abstract |
PROBLEM TO BE SOLVED: To measure a threshold voltage of a memory cell after emitting electrons without using a negative power supply and to provide a sense amplifier circuit even when measuring a negative threshold voltage. To determine the value of data accurately. SOLUTION: A memory cell array 1 formed in a P-type well 42 and a P-type well 42 are supplied with 0 V and a positive bias potential. A P-type well bias circuit 2 for biasing any one of VNCPAD1, a source line bias circuit 6 for biasing the source region of the memory cell to 0V and a positive bias potential VNCPAD1, a sensed read data, The sense amplifier circuit 13 for amplifying the sensed data, and the P-type well 42 and the source region are each connected to a positive bias potential VNCP. In this mode, data is read by biasing AD1 and using the gate of the memory cell as the read potential. And a VSAN supply circuit 15 for setting the source potential of the VSAN from 0 V to a positive bias potential VNCPAD1. |