Phase change memory cell including multiple phase change material portions
View Patent ↗A memory cell includes a first electrode, a second electrode, and a first portion of phase-change material contacting the first electrode. The memory cell includes a second portion of phase-change material contacting the second electrode and a third portion of phase-change material between the first portion and the second portion. A phase-change material composition of the third portion and the second portion gradually transitions from the third portion to the second portion.
1. A memory cell comprising:
a first electrode;
a second electrode;
a first portion of phase-change material contacting the first electrode;
a second portion of phase-change material contacting the second electrode; and
a third portion of phase-change material between the first portion and the second portion,
wherein a phase-change material composition of the third portion and the second portion gradually transitions from the third portion to the second portion, and
wherein the first portion has a first melting temperature, the second portion has a second melting temperature, and the third portion has a third melting temperature less than the first melting temperature and the second melting temperature.
2. A memory cell comprising:
a first electrode;
a second electrode;
a first portion of phase-change material contacting the first electrode;
a second portion of phase-change material contacting the second electrode; and
a third portion of phase-change material between the first portion and the second portion,
wherein a phase-change material composition of the third portion and the second portion gradually transitions from the third portion to the second portion,
wherein the phase-change material composition of the third portion and the second portion gradually transitions from the third portion comprising a doped phase-change material to the second portion comprising a differently doped or undoped phase-change material.
3. A memory cell comprising:
a first electrode;
a second electrode;
a first portion of phase-change material contacting the first electrode, the first portion comprising a first phase-change material;
a second portion of phase-change material contacting the second electrode, the second portion comprising a second phase-change material; and
a third portion of phase-change material contacting the first portion and the second portion and laterally surrounding the second portion, the third portion comprising a third phase-change material different than the first phase-change material and the second phase-change material.
4. The memory cell of claim 3 , wherein the first portion has a first resistivity, the second portion has a second resistivity, and the third portion has a third resistivity greater than the first resistivity and the second resistivity.
5. The memory cell of claim 3 , wherein the first portion has a first melting temperature, the second portion has a second melting temperature, and the third portion has a third melting temperature less than the first melting temperature and the second melting temperature.
6. The memory cell of claim 3 , wherein the third portion comprises a doped phase-change material and the first portion and the second portion comprise a differently doped or undoped phase-change material.
7. The memory cell of claim 3 , wherein the first portion, the second portion, and the third portion each comprises at least one of Ge, Sb, Te, Ga, As, In, Se, and S.
8. A memory cell comprising:
a first electrode;
a first contact contacting the first electrode;
a second electrode;
a second contact contacting the second electrode;
a first portion of phase-change material contacting the first contact, the first portion having a first phase-change material composition; and
a second portion of phase-change material contacting the first portion and the second contact, the second portion having a second phase-change material composition different than the first phase-change material composition,
wherein the first portion has a first melting temperature and the second portion has a second melting temperature less than the first melting temperature.
9. The memory cell of claim 8 , wherein the first portion has a first resistivity and the second portion has a second resistivity greater than the first resistivity.
10. The memory cell of claim 8 , wherein the first portion and the second portion each comprises at least one of Ge, Sb, Te, Ga, As, In, Se, and S.
11. A memory cell comprising:
a first electrode;
a second electrode;
a first portion of phase-change material contacting the first electrode;
a second portion of phase-change material contacting the second electrode; and
a third portion of phase-change material between the first portion and the second portion,
wherein a phase-change material composition of the third portion and the second portion gradually transitions from the third portion comprising a doped phase-change material to the second portion comprising a differently doped or undoped phase-change material.
12. The memory cell of claim 11 , wherein a phase-change material composition of the first portion and the third portion gradually transitions from the first portion comprising a differently doped or undoped phase-change material to the third portion.
13. The memory cell of claim 11 , wherein the first portion has a first resistivity, the second portion has a second resistivity, and the third portion has a third resistivity greater than the first resistivity and the second resistivity.
14. The memory cell of claim 11 , wherein the first portion has a first melting temperature, the second portion has a second melting temperature, and the third portion has a third melting temperature less than the first melting temperature and the second melting temperature.
15. The memory cell of claim 11 , wherein the first portion, the second portion, and the third portion each comprises at least one of Ge, Sb, Te, Ga, As, In, Se, and S.
16. A memory cell comprising:
a first electrode;
a second electrode;
a first portion of phase-change material contacting the first electrode, the first portion of phase-change material comprising a first phase-change material composition;
a second portion of phase-change material contacting the second electrode, the second portion of phase-change material comprising a second phase-change material composition; and
a third portion of phase-change material contacting the first portion and the second portion and laterally surrounding the second portion, the third portion of phase-change material comprising a third phase-change material composition different from the first phase-change material composition and the second phase-change material composition.
17. The memory cell of claim 16 , wherein the first phase-change material composition has a first resistivity, the second phase-change material composition has a second resistivity, and the third phase-change material composition has a third resistivity greater than the first resistivity and the second resistivity.
18. The memory cell of claim 16 , wherein the first phase-change material composition has a first melting temperature, the second phase-change material composition has a second melting temperature, and the third phase-change material composition has a third melting temperature less than the first melting temperature and the second melting temperature.
19. The memory cell of claim 16 , wherein the third phase-change material composition comprises a doped phase-change material and the first phase-change material composition and the second phase-change material composition comprise a differently doped or undoped phase-change material.
20. The memory cell of claim 16 , wherein the first phase-change material composition, the second phase-change material composition, and the third phase-change material composition each comprises at least one of Ge, Sb, Te, Ga, As, In, Se, and S.