Nonvolatile semiconductor memory device
A nonvolatile semiconductor memory device includes a selection transistor and a memory transistor that are formed on a well for each of a plurality of memory cells. At a time of a data read from the memory transistor, a first voltage is applied to the well and a source of the memory transistor, and a second voltage is applied to a gate of the selection transistor included in a non-selected memory cell among the plurality of memory cells. The first voltage is smaller than an absolute value of the second voltage.
1. A nonvolatile semiconductor memory device comprising:
a selection transistor and a memory transistor, that are p-channel field effect transistors, formed on a well for each of a plurality of memory cells,
wherein the nonvolatile semiconductor memory device performs a data read from the memory transistor in a state where
a first voltage is applied to the well and a source of the memory transistor,
a second voltage is applied to a gate of the selection transistor included in a non-selected memory cell among the plurality of memory cells, and
a third voltage is applied to a drain of the selection transistor,
wherein the second voltage is a positive voltage higher than the first voltage, and the first voltage is a positive voltage higher than the third voltage.
2. The nonvolatile semiconductor memory device as claimed in claim 1 , wherein the nonvolatile semiconductor memory device performs the data read from the memory transistor in the state where the first voltage is further applied to a control gate of the memory transistor.
3. The nonvolatile semiconductor memory device as claimed in claim 1 , further comprising:
a first control circuit configured to control a gate voltage of the selection transistor; and
a first input part configured to input a first power source voltage to the first control circuit,
wherein the first control circuit outputs the first power source voltage as the second voltage.
4. The nonvolatile semiconductor memory device as claimed in claim 3 , further comprising:
a second control circuit configured to control a voltage of the well and the source of the memory transistor; and
a second input part configured to input a second power source voltage lower than the first power source voltage to the second control circuit,
wherein the second control circuit outputs the second power source voltage as the first voltage.
5. The nonvolatile semiconductor memory device as claimed in claim 4 , further comprising:
a logic circuit configured to operate at the second power source voltage.
6. The nonvolatile semiconductor memory device as claimed in claim 3 , further comprising:
a step-down circuit configured to step down and lower the first power source voltage and generate the first voltage; and
a second control circuit configured to control a voltage of the well and the source of the memory transistor,
wherein the second control circuit outputs the first voltage generated by the step-down circuit.
7. The nonvolatile semiconductor memory device as claimed in claim 1 , wherein the nonvolatile semiconductor memory device performs the data read from the memory transistor in the state where the third voltage is applied to the gate of the selection transistor included in a selected memory cell among the plurality of memory cells.
8. The nonvolatile semiconductor memory device as claimed in claim 7 , wherein the third voltage is zero.
9. The nonvolatile semiconductor memory device as claimed in claim 1 , wherein a threshold voltage of the selection transistor is higher than or equal to a gate-source voltage of the selection transistor included in a selected memory cell among the plurality of memory cells, and lower than or equal to a gate-source voltage of the selection transistor included in the non-selected memory cell among the plurality of memory cells.
10. A nonvolatile semiconductor memory device comprising:
a selection transistor and a memory transistor, that are n-channel field effect transistors, formed on a well for each of a plurality of memory cells,
wherein the nonvolatile semiconductor memory device performs a data read from the memory transistor in a state where
a first voltage is applied to the well and a source of the memory transistor,
a second voltage is applied to a gate of the selection transistor included in a non-selected memory cell among the plurality of memory cells, and
a third voltage is applied to a drain of the selection transistor,
wherein the second voltage is lower than the first voltage, and the third voltage is a positive voltage higher than the first voltage.
11. The nonvolatile semiconductor memory device as claimed in claim 10 , wherein the nonvolatile semiconductor memory device performs the data read from the memory transistor in the state where the first voltage is further applied to a control gate of the memory transistor.
12. The nonvolatile semiconductor memory device as claimed in claim 10 , wherein the nonvolatile semiconductor memory device performs the data read from the memory transistor in the state where a fourth voltage is applied to the gate of the selection transistor included in a selected memory cell among the plurality of memory cells, and the fourth voltage is a positive voltage higher than the third voltage.
13. The nonvolatile semiconductor memory device as claimed in claim 12 , wherein the first voltage is zero, and the second voltage is a negative voltage.
14. The nonvolatile semiconductor memory device as claimed in claim 12 , wherein the first voltage is a positive voltage, and the second voltage is zero.
15. The nonvolatile semiconductor memory device as claimed in claim 10 , wherein a threshold voltage of the selection transistor is higher than or equal to a gate-source voltage of the selection transistor included in the non-selected memory cell among the plurality of memory cells, and lower than or equal to a gate-source voltage of the selection transistor included in a selected memory cell among the plurality of memory cells.