Programming memory cells using asymmetric current pulses
The present disclosure includes apparatuses and methods for programming memory cells using asymmetric current pulses. An embodiment includes a memory having a plurality of self-selecting memory cells, and circuitry configured to program a self-selecting memory cell of the memory by applying a first current pulse or a second current pulse to the self-selecting memory cell, wherein the first current pulse is applied for a longer amount of time than the second current pulse and the first current pulse has a lower amplitude than the second current pulse.
1. An apparatus, comprising:
a memory having a plurality of self-selecting memory cells; and
circuitry configured to program a self-selecting memory cell of the memory by:
applying a first current pulse or a second current pulse to the self-selecting memory cell, wherein:
the first current pulse is applied for a longer amount of time than the second current pulse; and
the first current pulse has a lower amplitude than the second current pulse; and
applying a third current pulse and a fourth current pulse to the self-selecting memory cell.
2. The apparatus of claim 1 , wherein the self-selecting memory cells include a chalcogenide material.
3. The apparatus of claim 1 , wherein the first current pulse is a set pulse.
4. The apparatus of claim 1 , wherein the second current pulse is a reset pulse.
5. The apparatus of claim 1 , wherein the first current pulse has a negative polarity.
6. The apparatus of claim 5 , wherein applying the first current pulse decreases a magnitude of a threshold voltage (Vt) of the self-selecting memory cell.
7. The apparatus of claim 1 , wherein the second current pulse has a positive polarity.
8. The apparatus of claim 7 , wherein applying the second current pulse increases a magnitude of a threshold voltage (Vt) of the self-selecting memory cell.
9. An apparatus, comprising:
a memory having a plurality of self-selecting memory cells; and
circuitry configured to program a self-selecting memory cell of the memory by:
applying a first current pulse, or a second current pulse to the self-selecting memory cell, wherein:
the second current pulse is applied for a shorter amount of time than the first current pulse;
the second current pulse has a greater amplitude than the first current pulse; and
the second current pulse has an opposite polarity than the first current pulse; and
applying a third current pulse and a fourth current pulse to the self-selecting memory cell, wherein the third current pulse has an opposite polarity of whichever one of the first current pulse or the second pulse that is applied to the self-selecting memory cell and the fourth current pulse has an opposite polarity of the third current pulse.
10. The apparatus of claim 9 , wherein applying the first current pulse and the second current pulse to the self-selecting memory cell increases a difference between a magnitude of a first threshold voltage (Vt) of the self-selecting memory cell and a magnitude of a second Vt of the self-selecting memory cell by a range of approximately 20-30%.
11. The apparatus of claim 9 , wherein the first current pulse has an amplitude of 30 microAmps (μA) or less.
12. The apparatus of claim 9 , wherein the first current pulse is applied to the self-selecting memory cell for 60 nanoseconds (ns) or more.
13. The apparatus of claim 9 , wherein the second current pulse is applied to the self-selecting memory cell for 20 nanoseconds (ns) or less.
14. The apparatus of claim 9 , wherein the second current pulse is applied to the self-selecting memory cell for approximately 40 nanoseconds (ns).
15. The apparatus of claim 9 , wherein the second current pulse has an amplitude of approximately 60 microAmps (μA).
16. A method, comprising:
programming a self-selecting memory cell by:
applying a first current pulse to the self-selecting memory cell or applying a second current pulse to the self-selecting memory cell, wherein:
an amplitude of the second pulse is higher than an amplitude of the first pulse;
the second pulse is applied for a shorter amount of time than the first pulse; and
the second pulse has an opposite polarity than the first pulse; and
applying a third current pulse and a fourth current pulse to the self-selecting memory cell.
17. The method of claim 16 , wherein:
applying the first current pulse to the self-selecting memory cell programs the self-selecting memory cell to a first data state; and
applying the second current pulse to the self-selecting memory cell programs the self-selecting memory cell to a second data state.
18. The method of claim 17 , wherein applying the third current pulse to the self-selecting memory cell programs the self-selecting memory cell to an opposite data state of whichever of the first data state or the second data state in which the self-selecting memory cell is programmed.
19. A method, comprising:
applying a first current pulse to a self-selecting memory cell; or
applying a second current pulse to the self-selecting memory cell, wherein:
the second current pulse is applied for a shorter amount of time than the first current pulse;
the second current pulse has a higher amplitude than the first current pulse; and
the second current pulse has an opposite polarity than the first current pulse; and
applying a third current pulse and a fourth current pulse to the self-selecting memory cell.
20. The apparatus of claim 19 , wherein the first current pulse and the second current pulse are applied for a same amount of time and have different amplitudes.
21. The apparatus of claim 19 , wherein the first current pulse and the second current pulse are applied for different amounts of time and have a same amplitude.
22. The apparatus of claim 19 , wherein the first pulse and the third pulse are applied for a same amount of time and have a same amplitude.
23. The apparatus of claim 19 , wherein the second current pulse and the third current pulse are applied for a same amount of time and have different amplitudes.
24. The apparatus of claim 19 , wherein the third current pulse and the fourth current pulse are applied for a same amount of time and have different amplitudes.
25. The apparatus of claim 19 , wherein the third current pulse and the fourth current pulse are applied for different amounts of time and have a same amplitude.