Method of producing transition metal dichalcogenide layer
Method of producing one or more transition metal dichalcogenide (MX 2 ) layers on a substrate, comprising the steps of: obtaining a substrate having a surface and depositing MX 2 on the surface using ALD deposition, starting from a metal halide precursor and a chalcogen source (H 2 X), at a deposition temperature of about 300° C. Suitable metals are Mo and W, suitable chalcogenides are S, Se and Te. The substrate may be (111) oriented. Also mixtures of two or more MX 2 layers of different compositions can be deposited on the substrate, by repeating at least some of the steps of the method.
1. A method of producing at least one transition metal dichalcogenide layer (MX 2 ) on a substrate, the method comprising:
obtaining a substrate having a surface;
functionalizing the surface before depositing a transition metal dichalcogenide layer (MX 2 ); and
depositing the transition metal dichalcogenide layer (MX 2 ) on the surface using ALD deposition, starting from a metal halide precursor and a chalcogen source (H 2 X).
2. The method according to claim 1 , wherein the surface comprises at least one layer of dielectric.
3. The method according to claim 2 , wherein the at least one layer of dielectric comprises at least one of: Si 3 N 4 , SiO 2 , Al 2 O 3 , HfO 2 , or ZrO 2 .
4. The method according to claim 2 , wherein the at least one layer of dielectric is formed via epitaxial growth.
5. The method according to claim 1 , wherein the surface comprises a sacrificial layer.
6. The method according to claim 1 , wherein functionalizing the surface comprises functionalizing the surface with at least one of: SiH 4 , Si 2 H 2 , Si 2 H 6 , Si 3 H 8 , B 2 H 6 , or a combination thereof.
7. The method according to claim 1 , wherein functionalizing the surface comprises an O 3 oxidation at 40° C. to 80° C. for 200 to 1000 msec.
8. The method according to claim 1 , wherein functionalizing the surface comprises annealing the substrate with H 2 S at a temperature in the range of 300° C. to 550° C. during a period ranging from 1 to 40 minutes.
9. The method according to claim 1 , wherein depositing the transition metal dichalcogenide layer (MX 2 ) on the surface using ALD deposition comprises depositing the transition metal dichalcogenide layer (MX 2 ) on the surface using Plasma Enhanced ALD deposition.
10. The method according to claim 1 , wherein depositing the transition metal dichalcogenide layer (MX 2 ) is performed at a deposition temperature in the range of 250° C. to 450° C.
11. The method according to claim 1 , further comprising removing a native oxide from the surface.
12. The method according to claim 11 , wherein removing the native oxide comprises HF/H 2 O dipping the substrate.
13. The method according to claim 12 , wherein removing the native oxide further comprises H 2 baking of the substrate during at least 5 minutes at a temperature in the range of 700° C. to 800° C.
14. The method according to claim 1 , wherein a metal of the metal halide precursor is selected from the group consisting of Mo and W, and wherein a chalcogen of the chalcogen source (H 2 X) is selected from the group consisting of S, Se, and Te.
15. The method according to claim 1 , wherein the substrate comprises a (111) oriented semiconductor substrate or a substrate having a surface which is suitable for epitaxial seeding of a transition metal dichalcogenide layer.
16. A method of producing at least two transition metal dichalcogenide materials on a substrate, the method comprising:
providing a first metal dichalcogenide material on the substrate using the method of claim 1 , thereby using a first metal halide precursor and a first chalcogen source; and
providing a second metal dichalcogenide material on the substrate by using ALD deposition, starting from a second metal halide precursor and a second chalcogen source, wherein the first metal halide precursor is different from the second metal halide precursor and/or the first chalcogen source is different from the second chalcogen source.
17. The method according to claim 1 , further comprising providing a sulphur layer on the surface.
18. The method according to claim 17 , further comprising exposing the substrate to a plurality of gas pulses, wherein the gas pulses comprise at least one of: WF 6 , Si 2 H 6 , H 2 S, or an inert gas.
19. The method according to claim 17 , wherein providing the sulphur layer comprises exposing the substrate to H 2 S.