Formation of crystalline, layered transition metal dichalcogenides
Embodiments of the present disclosure relate to forming a two-dimensional crystalline dichalcogenide by positioning a substrate in an annealing apparatus. The substrate includes an amorphous film of a transition metal and a chalcogenide. The film is annealed at a temperature from 500° C. to 1200° C. In response to the annealing, a two-dimensional crystalline structure is formed from the film. The two-dimensional crystalline structure is according to a formula MX 2 , M includes one or more of molybdenum (Mo) or tungsten (W) and X includes one or more of sulfur (S), selenium (Se), or tellurium (Te).
1. A method for substrate processing, comprising:
positioning a substrate in an annealing apparatus, wherein the substrate comprises an amorphous film of a transition metal and a chalcogenide;
annealing the amorphous film at a temperature from 500° C. to 1200° C.; and
forming, in response to the annealing, a two-dimensional crystalline structure from the amorphous film, wherein the two-dimensional crystalline structure is according to a formula MX 2 , and wherein M comprises molybdenum (Mo) or tungsten (W) and X comprises sulfur (S), selenium (Se), or tellurium (Te), wherein the amorphous film comprises an impurity, wherein a ratio of the impurity to the M element of the two-dimensional crystalline structure (impurity: M) is from 0.50:1 to 2.00:1.
2. The method of claim 1 , wherein the substrate comprises a metal, a semiconductor, a polymer, an inorganic oxide, a metal oxide, a metal sulfide, a metal selenide, an inorganic sulfide, graphene, an inorganic selenide, or combinations thereof.
3. The method of claim 1 , wherein the two-dimensional crystalline structure comprises a plurality of monolayers.
4. The method of claim 1 , wherein the annealing further comprises annealing in an atmosphere comprising argon (Ar) and nitrogen (N 2 ).
5. The method of claim 1 , wherein the annealing further comprises exposing the amorphous film to hydrogen sulfide (H 2 S) and hydrogen selenide (H 2 Se).
6. The method of claim 1 , where the amorphous film comprises a thickness from 0.5 nm to 100 nm, and wherein the two-dimensional crystalline structure comprises a thickness from 50% to 80% of the thickness of the amorphous film.
7. The method of claim 1 , wherein the annealing apparatus comprises a hot pedestal, a hot furnace, a microwave annealing apparatus, a lamp-based rapid thermal processing (RTP) apparatus, or a laser annealing apparatus.
8. The method of claim 1 , wherein the substrate comprises SiO 2 , or Si 3 N 4 .
9. The method of claim 1 , wherein the impurity comprises carbon, nitrogen, or silicon.
10. A method for substrate processing, comprising:
positioning a substrate in a laser annealing apparatus, wherein the substrate comprises an amorphous film comprising a transition metal and a chalcogenide;
annealing the amorphous film in the laser annealing apparatus at a temperature from 800° C. to 1200° C.; and
forming, in response to the annealing, a two-dimensional crystalline structure from the amorphous film, wherein the two-dimensional crystalline structure is according to a formula MX 2 , and wherein M comprises molybdenum (Mo) or tungsten (W) and X comprises sulfur (S), selenium (Se), or tellurium (Te),wherein the amorphous film comprises an impurity, wherein a ratio of the
annealing the amorphous film using the RTP apparatus at a temperature from 800° C. to 1200° C.; and
forming, in response to the annealing, a two-dimensional crystalline structure from the amorphous film, wherein the two-dimensional crystalline structure is according to a formula MX 2 , wherein M comprises molybdenum (Mo) or tungsten (W) and X comprises sulfur (S), selenium (Se), or tellurium (Te), wherein the amorphous film comprises an impurity, wherein a ratio of the impurity to the M element of the two-dimensional crystalline structure (impurity: M) is from 0.50:1 to 2.00:1.
11. The method of claim 10 , wherein the substrate comprises a metal, a semiconductor, a polymer, an inorganic oxide, a metal oxide, a metal sulfide, a metal selenide, an inorganic sulfide, graphene, an inorganic selenide, or combinations thereof.
12. The method of claim 10 , wherein the annealing further comprises annealing in an atmosphere comprising argon (Ar) and nitrogen (N 2 ).
13. The method of claim 12 , wherein the annealing further comprises exposing the amorphous film to hydrogen sulfide (H 2 S) and hydrogen selenide (H 2 Se).
14. The method of claim 10 , wherein the two-dimensional crystalline structure comprises a thickness from 50% to 80% of a thickness of the amorphous film.
15. The method of claim 10 , wherein the annealing apparatus comprises a 532 nm laser apparatus and the annealing is for a period of time from about 1 ns to about 500 ns.
16. The method of claim 10 , wherein the annealing apparatus comprises a 810 nm laser apparatus the annealing is for a period of time from 1 μs to 1000 μs.
17. A method for substrate processing, comprising:
positioning a substrate in a rapid thermal processing (RTP) apparatus, wherein the substrate comprises an amorphous film formed over the substrate; according to a formula MX 2 , and wherein M comprises molybdenum (Mo) or tungsten (W) and X comprises sulfur (S), selenium (Se), or tellurium (Te), wherein the amorphous film comprises a second plurality of impurities, wherein a ratio of the second plurality of impurities to the M element of the two-dimensional crystalline structure (second plurality of impurities: M) is from 0.50:1 to 2.00:1;
exposing, during the annealing, the amorphous film to hydrogen sulfide (H 2 S) and hydrogen selenide (H 2 Se); and
removing the interface layer.
18. The method of claim 17 , wherein the substrate comprises silicon (Si) and a layer of SiO 2 is formed on the substrate, wherein the amorphous film is formed over the layer of SiO 2 .
19. The method of claim 17 , wherein the impurity comprises carbon, nitrogen, or silicon.
20. The method of claim 17 , wherein the two-dimensional crystalline structure comprises a thickness from 50% to 80% of a thickness of the amorphous film.
21. A method for substrate processing, comprising:
positioning a substrate in an annealing apparatus, wherein the substrate comprises an amorphous film of a transition metal and a chalcogenide;
annealing the amorphous film at a temperature from 500° C. to 1200° C. to form a two-dimensional crystalline structure from the amorphous film and an interface layer in contact with the two-dimensional crystalline structure, the interface layer including a first plurality of impurities released from the amorphous film during the annealing, wherein the two-dimensional crystalline structure is impurity to the M element of the two-dimensional crystalline structure (impurity: M) is from 0.50:1 to 2.00:1.