Pinched center resistive change memory cell
View Patent ↗A vertically oriented memory element having a narrower area near its center away from its ends is formed. Current density and heating are higher away from the ends of the memory element, thus increasing its lifetime.
1. A memory cell comprising:
a substrate comprising one or more dielectric materials;
disposed within the substrate, a current-steering element; and
disposed within the substrate and above and in contact with the current steering-element, an information storage element, the information storage element comprising a programmable data-storage material shaped to define (i) a first end region, (ii) a center region disposed over the first end region, and (iii) a second end region disposed over the center region,
wherein (i) a cross-sectional area of the center region is smaller than a cross-sectional area of the first end region, (ii) the cross-sectional area of the center region is smaller than a cross-sectional area of the second end region, (iii) the data-storage material comprises a phase-change material or a resistive-change material, and (iv) the data-storage material is configured for programmability via the current-steering element such that (a) a current density within the center region is larger than a current density within the first end region and (b) the current density within the center region is larger than a current density within the second end region.
2. The memory cell of claim 1 , wherein the substrate comprises (i) a first material surrounding the center region of the information storage element and (ii) a second material surrounding the first and second end regions of the information storage element, the second material being different from the first material.
3. The memory cell of claim 2 , wherein the first material comprises a first dielectric material.
4. The memory cell of claim 3 , wherein the second material comprises a second dielectric material different from the first dielectric material.
5. The memory cell of claim 2 , wherein the first material comprises a nitride material.
6. The memory cell of claim 2 , wherein the first material comprises silicon.
7. The memory cell of claim 2 , wherein the first material comprises silicon nitride.
8. The memory cell of claim 2 , wherein the second material comprises silicon dioxide.
9. The memory cell of claim 1 , further comprising a liner material (i) surrounding at least a portion of the second end region of the information storage element and (ii) disposed between the second end region of the information storage element and the substrate.
10. The memory cell of claim 9 , wherein the liner material comprises a metal.
11. The memory cell of claim 9 , wherein the liner material comprises titanium.
12. The memory cell of claim 1 , wherein the surrounding substrate is in conformal contact with the center region and first and second end regions of the information storage element.
13. The memory cell of claim 1 , wherein a top surface of the second end region is substantially coplanar with a top surface of the substrate.
14. The memory cell of claim 1 , wherein the data-storage material comprises a phase-change material.
15. The memory cell of claim 14 , wherein the phase-change material comprises a chalcogenide material.
16. The memory cell of claim 1 , wherein the data-storage material comprises a resistive-change material.