Programming a memory device
View Patent ↗A method of programming a memory cell in a non-volatile memory device includes applying a first voltage to a control gate associated with the memory cell and applying a second voltage to a drain region associated with the memory cell. The method also includes applying a positive bias to a source region associated with the memory cell and/or applying a negative bias to a substrate region associated with the memory cell.
1. In a non-volatile memory device comprising a plurality of memory cells, each of the plurality of memory cells comprising a source, a drain, a dielectric layer formed on a substrate, a charge storage element comprising silicon nitride formed on the dielectric layer, an inter-gate dielectric formed on the charge storage element, and a control gate formed on the inter-gate dielectric, a method of programming at least one of the memory cells, comprising:
applying a first voltage to the control gate;
applying a second voltage to the drain the second voltage ranging from about 3 volts to about 5 volts; and
applying at least one of a positive bias to the source or a negative bias to the substrate,
wherein the charge storage element in each of the plurality of memory cells is configured to store charges representing two bits of information and applying the first and second voltages and at least one of the positive bias or the negative bias comprises:
applying the first and second voltages and at least one of the positive bias or the negative bias for a duration ranging from about 0.1 microseconds (μs) to about 5 μs.
2. The method of claim 1 , wherein the first voltage ranges from about 9 volts to about 10 volts, and applying at least one of a positive bias to the source or a negative bias to the substrate comprises:
applying a positive bias to the source ranging from about 0.2 volts to about 1.5 volts.
3. The method of claim 2 , wherein the positive bias is about 0.8 volts.
4. The method of claim 3 , further comprising:
grounding the substrate.
5. The method of claim 1 , wherein the applying at least one of a positive bias to the source or a negative bias to the substrate comprises:
applying a negative bias to the substrate ranging from about −0.2 volts to about −1.5 volts.
6. The method of claim 5 , wherein the negative bias is about −0.8 volts.
7. The method of claim 1 , wherein the applying at least one of a positive bias to the source or a negative bias to the substrate comprises:
applying a positive bias to the source and a negative bias to the substrate.
8. The method of claim 1 , wherein the applying at least one of a positive bias to the source or a negative bias to the substrate reduces programming current associated with programming the at least one memory cell relative to programming the at least one memory cell without applying at least one of the positive bias or negative bias.
9. A method for programming memory cells in a non-volatile memory device, each of the memory cells including a dielectric charge storage element, the method comprising:
selecting a first group of memory cells to be programmed;
applying a first voltage to a word line associated with the first group of memory cells for a duration ranging from about 0.1 microseconds (μs) to about 5 μs;
applying a second voltage to a drain line associated with the first group of memory cells for a duration ranging from about 0.1 μs to about 5 μs; and
applying at least one of a positive voltage to a source line associated with the first group of memory cells or a negative voltage to a substrate region associated with the first group of memory cells for a duration ranging from about 0.1 μs to about 5 μs.
10. The method of claim 9 , wherein the applying at least one of a positive voltage to a source line or a negative voltage to a substrate region comprises:
applying a positive voltage to the source line ranging from about 0.2 volts to about 1.5 volts.
11. The method of claim 9 , wherein the applying at least one of a positive voltage to a source line or a negative voltage to a substrate region comprises:
applying a negative voltage to the substrate region ranging from about −0.2 volts to about −1.5 volts.
12. The method of claim 9 , wherein the applying at least one of a positive voltage to a source line or a negative voltage to a substrate region comprises:
applying a positive voltage to the source line and a negative voltage to the substrate region.
13. The method of claim 12 , wherein the positive voltage ranges from about 0.2 volts to about 1.5 volts and the negative voltage ranges from about −0.2 volts to about −1.5 volts.
14. The method of claim 9 , wherein the dielectric charge store element in each of the memory cells in the non-volatile memory device comprises silicon nitride configured to store charges representing two or more bits of information.
15. An integrated circuit, comprising:
a plurality of memory cells, each of the plurality of memory cells comprising a dielectric charge storage element; and
a controller configured to program a first one of the plurality of memory cells, wherein when programming the first memory cell, the controller is configured to:
apply a first voltage to a control gate associated with the first memory cell for a duration ranging from about 0.1 microseconds (μs) to about 5 μs,
apply a second voltage to a drain region associated with the first memory cell for a duration ranging from about 0.1 μs to about 5 μs,
apply a third voltage to a source region associated with the first memory cell for a duration ranging from about 0.1 μs to about 5 μs, and
apply a fourth voltage to a substrate region associated with the first memory cell for a duration ranging from about 0.1 μs to about 5 μs.
16. The integrated circuit of claim 15 , wherein the third voltage ranges from about 0.2 volts to about 1.5 volts.
17. The integrated circuit of claim 16 , wherein the fourth voltage ranges from about −0.2 volts to about −1.5 volts.
18. The integrated circuit of claim 16 , wherein the first voltage ranges from about 9 volts to about 10 volts and the second voltage ranges from about 3 volts to about 5 volts.
19. The integrated circuit of claim 15 , wherein the charge storage element in each of the plurality of memory cells comprises silicon nitride configured to store charges representing at least two bits of information.