Method for encapsulating a chalcogenide material
Methods of depositing silicon nitride encapsulation layers by atomic layer deposition over memory devices including chalcogenide material are provided herein. Methods include using iodine-containing silicon precursors and depositing thermally using ammonia or hydrazine as a second reactant, or iodine-containing silicon precursors and depositing using a nitrogen-based or hydrogen-based plasma.
1. A method of encapsulating chalcogenide material, the method comprising:
(a) providing a substrate to a chamber, the substrate comprising one or more exposed layers of the chalcogenide material;
(b) exposing the substrate to diiodosilane under conditions allowing the diiodosilane to adsorb onto a surface of the substrate, thereby forming an adsorbed layer of the diiodosilane; and
(c) exposing the substrate to a second reactant to form a silicon nitride film on the chalcogenide material.
2. The method of claim 1 , wherein the second reactant is selected from the group consisting of ammonia and hydrazines, and wherein the silicon nitride is deposited at a temperature less than about 300° C.
3. The method of claim 1 , further comprising igniting a plasma when exposing the substrate to the second reactant to generate a reactive species.
4. The method of claim 3 , wherein the second reactant is selected from the group consisting of nitrogen and hydrogen.
5. The method of claim 1 , wherein the second reactant forms a volatile species when reacted with a material selected from the group consisting of aluminum, iron, copper, antimony, selenium, tellurium, germanium, and arsenic.
6. The method of claim 1 , wherein the chalcogenide material is selected from the group consisting of sulfur, selenium, tellurium, and combinations thereof.
7. The method of claim 1 , wherein the silicon nitride film deposited has a step coverage of at least about 95%.
8. The method of claim 1 , wherein the silicon nitride film is deposited to a thickness greater than about 30 Å.
9. The method of claim 1 , wherein the chamber is purged during at least one of: (i) after performing (b) and prior to performing (c); and (ii) after performing (c).
10. The method of claim 1 , wherein (b) and (c) are repeated sequentially.
11. The method of claim 9 , wherein the chamber is purged by flowing a purge gas selected from the group consisting of argon, helium, nitrogen, and hydrogen.
12. The method of claim 1 , further comprising depositing a second layer over the substrate, wherein the layer is deposited with a step coverage of between about 30% and about 90%.
13. The method of claim 12 , wherein the second layer is deposited by remote plasma chemical vapor deposition.
14. The method of claim 12 , wherein the second layer is deposited by plasma enhanced chemical vapor deposition.
15. The method of claim 12 , wherein the second layer comprises silicon nitride.
16. The method of claim 12 , wherein the second layer comprises silicon carbide.
17. The method of claim 12 , wherein the substrate comprises one or more features, and wherein the second layer is deposited non-conformally such that thickness of the second layer on a sidewall of at least one of the one or more features is greater at the top of the at least one of the one or more features than thickness of the second layer on the sidewall of the at least one of the one or more features at the bottom of the at least one of the one or more features.
18. A method of encapsulating chalcogenide material, the method comprising:
(a) providing a substrate to a chamber, the substrate comprising one or more exposed layers of the chalcogenide material;
(b) exposing the substrate to a chlorine-free iodine-containing silicon precursor under conditions allowing the chlorine-free iodine-containing silicon precursor to adsorb onto a surface of the substrate, thereby forming an adsorbed layer of the chlorine-free iodine-containing silicon precursor;
(c) exposing the substrate to a second reactant to form a silicon nitride film on the chalcogenide material; and
(d) igniting a plasma when exposing the substrate to the second reactant to generate a reactive species.
19. A method of encapsulating chalcogenide material, the method comprising:
(a) providing a substrate to a chamber, the substrate comprising one or more exposed layers of the chalcogenide material;
(b) exposing the substrate to hexaiodosilane under conditions allowing the hexaiodosilane to adsorb onto a surface of the substrate, thereby forming an adsorbed layer of the hexaiodosilane; and
(c) exposing the substrate to a second reactant to form a silicon nitride film on the chalcogenide material.