Nonvolatile semiconductor storage device
View Patent ↗A nonvolatile memory device of the present invention performs a programming operation by accumulating a charge in certain capacitance which is provided for each programming memory cell and injecting hot electrons generated when the charge is discharged via the memory cell into a floating gate. Thus, a variation in a programming characteristic of the nonvolatile semiconductor memory device is reduced, thereby realizing high-speed programming operation.
1. A nonvolatile semiconductor memory device wherein programming or erase is performed by discharging a charge accumulated in capacitance via a memory cell and injecting hot electrons generated by the discharge into a charge-injected portion of the memory cell, wherein the capacitance is stray capacitance of a bit line.
2. The nonvolatile semiconductor memory device according to claim 1 , wherein the charge-injected portion is a floating gate.
3. The nonvolatile semiconductor memory device according to claim 1 , wherein the charge-injected portion is a silicon nitride film.
4. The nonvolatile semiconductor memory device according to claim 1 , wherein a portion of the stray capacitance is formed of pn junction capacitance of a diffusion layer of the memory cell.
5. The nonvolatile semiconductor memory device according to claim 1 , wherein an internal power source circuit for generating a voltage to be applied to a bit line is brought to an inactive state when a charge is injected to the charge-injected portion.
6. The nonvolatile semiconductor memory device according to claim 1 , wherein, after the programming or the erase is performed a plurality of times, an operation of verifying a threshold voltage of the memory cell is performed.
7. The nonvolatile semiconductor memory device according to claim 6 , wherein the number of repeating the programming or the erase is incremented every time the threshold voltage verification operation is performed.
8. A nonvolatile semiconductor memory device wherein capacitance is charged via a memory cell and hot electrons generated by the charging are injected into a charge-injected portion of the memory cell so as to perform programming or erase, wherein the capacitance is stray capacitance of a bit line.
9. The nonvolatile semiconductor memory device according to claim 8 , wherein the charge-injected portion is a floating gate.
10. The nonvolatile semiconductor memory device according to claim 8 , wherein the charge-injected portion is a silicon nitride film.
11. The nonvolatile semiconductor memory device according to claim 8 , wherein a portion of the stray capacitance is formed of pn junction capacitance of a diffusion layer of the memory cell.
12. The nonvolatile semiconductor memory device according to claim 8 , wherein, after the programming or the erase is performed a plurality of times, an operation of verifying a threshold voltage of the memory cell is performed.
13. The nonvolatile semiconductor memory device according to claim 12 , wherein the number of repeating the programming or the erase is incremented every time the threshold voltage verification operation is performed.