Methods and apparatus for three-dimensional non-volatile memory
An apparatus is provided that includes a bit line above a substrate, a word line above the substrate, and a non-volatile memory cell between the bit line and the word line. The non-volatile memory cell includes a reversible resistance-switching memory element coupled in series with an isolation element. The isolation element includes a first selector element coupled in series with a second selector element. The first selector element includes a first snapback current, and the second selector element includes a second snapback current lower than the first snapback current.
1. Apparatus comprising:
a bit line above a substrate;
a word line above the substrate; and
a non-volatile memory cell between the bit line and the word line, the non-volatile memory cell comprising a reversible resistance-switching memory element coupled in series with an isolation element,
wherein:
the isolation element comprises a first selector element coupled in series with a second selector element; and
the first selector element comprises a first snapback current, the second selector element comprises a second snapback current lower than the first snapback current.
2. The apparatus of claim 1 , wherein the first selector element comprises a first selector leakage current, the second selector element comprises a second selector leakage current, and the first selector leakage current is less than second selector leakage current.
3. The apparatus of claim 1 , wherein the first selector element comprises a first selector leakage current, the second selector element comprises a second selector leakage current, the reversible resistance-switching memory element comprises a memory element leakage current, and one of the first selector leakage current and the second selector leakage current substantially equals the memory element leakage current.
4. The apparatus of claim 1 , wherein the first selector element comprises a first threshold voltage, the second selector element comprises a second threshold voltage, and the first threshold voltage is lower than the second threshold voltage.
5. The apparatus of claim 4 , wherein the second selector element comprises a voltage drop in a low resistance state, wherein the voltage drop substantially equals the second threshold voltage.
6. The apparatus of claim 1 , wherein the first selector element and the second selector element each comprise a volatile conductive bridge.
7. The apparatus of claim 1 , wherein the first selector element and the second selector element each comprise a correlated electronic switch.
8. The apparatus of claim 1 , wherein the reversible resistance-switching memory element comprises a phase change memory element.
9. The apparatus of claim 1 , wherein the reversible resistance-switching memory element comprises a non-volatile memory material.
10. The apparatus of claim 9 , wherein the non-volatile memory material comprises one or more of a phase change material, a ferroelectric material, a metal oxide, and a barrier modulated switching structure.
11. The apparatus of claim 1 , wherein the reversible resistance-switching memory element comprises a magnetic tunnel junction-based memory device.
12. Apparatus comprising:
a non-volatile memory cell disposed between a bit line and a word line, the non-volatile memory cell comprising:
a reversible resistance-switching memory element coupled in series with an isolation element; and
a capacitor coupled between the isolation element and the reversible resistance-switching memory element.
13. The apparatus of claim 12 , wherein the isolation element comprises a first selector element, and the capacitor is coupled between the first selector element and the reversible resistance-switching memory element.
14. The apparatus of claim 12 , wherein the isolation element comprises a first selector element and a second selector element, and the capacitor is coupled between the first selector element and the second selector element.
15. The apparatus of claim 12 , wherein the isolation element comprises a first selector element coupled in series with a second selector element, the first selector element comprises a first selector switching time, and the second selector element comprises a second selector switching time greater than the first selector switching time.
16. The apparatus of claim 12 , wherein the isolation element comprises a first selector element coupled in series with a second selector element, wherein the first selector element comprises a first selector leakage current, and the second selector element comprises a second selector leakage current greater than the first selector leakage current.
17. The apparatus of claim 12 , wherein the non-volatile memory cell further comprises a resistor coupled between the reversible resistance-switching memory element coupled and the isolation element.
18. The apparatus of claim 12 , wherein the isolation element comprises a correlated electronic switch.
19. The apparatus of claim 12 , wherein the reversible resistance-switching memory element comprises a phase change memory element.
20. The apparatus of claim 12 , wherein the reversible resistance-switching memory element comprises one or more of a phase change material, a ferroelectric material, a metal oxide, and a barrier modulated switching structure.
21. A method comprising:
forming a non-volatile memory cell between a bit line and a word line, the non-volatile memory cell comprising a selector element coupled in series with a reversible resistance-switching memory element; and
forming a capacitor between the selector element and the reversible resistance-switching memory element,
wherein the capacitor has a value that substantially matches a parasitic capacitance of the bit line and the word line.