Low temperature growth of transition metal chalcogenides
Transition metal dichalcogenide films and methods for depositing transition metal dichalcogenide films on a substrate are described. Methods for converting transition metal oxide films to transition metal dichalcogenide films are also described. The substrate is exposed to a precursor and a chalcogenide reactant to form the transition metal dichalcogenide film. The exposures can be sequential or simultaneous.
1. A method of depositing a film, the method comprising:
forming a transition metal oxide film on a substrate surface, forming the transition metal oxide film comprises forming a transition metal film followed by oxidizing the transition metal film by exposing the transition metal film to a plasma treatment of one or more of O 2 or O 3 to form the transition metal oxide film; and
converting the transition metal oxide film to a transition metal dichalcogenide film.
2. The method of claim 1 , wherein the transition metal oxide film is converted to the transition metal dichalcogenide film after forming the transition metal oxide film having a thickness in a range of from 15 Å to 25 Å.
3. The method of claim 2 , further comprising repeating forming the transition metal oxide film and converting the transition metal oxide film to form a transition metal dichalcogenide film with a final thickness up to 200 Å.
4. The method of claim 1 , wherein the substrate surface comprises a dielectric material and a conductive material.
5. The method of claim 4 , wherein the transition metal oxide film forms selectively on the dielectric material.
6. The method of claim 1 , wherein converting the transition metal oxide film to the transition metal dichalcogenide film is conducted at a temperature in a range of from 350° C. to 500° C. and at a pressure in a range of from 1 Torr to 10 Torr.
7. The method of claim 1 , wherein converting the transition metal oxide film to the transition metal dichalcogenide film is conducted for a time period in a range of from 30 minutes to 60 minutes.
8. The method of claim 1 , wherein converting the transition metal oxide film to the transition metal dichalcogenide film comprises pulsing the transition metal oxide film with one or more of sulfur (S), selenium (Se) and tellurium (Te).
9. A method of depositing a film, the method comprising:
forming a transition metal dichalcogenide film in a process cycle consisting essentially of sequential exposure of a substrate to a transition metal oxide precursor, a purge gas, a chalcogenide reactant, and purge gas.
10. The method of claim 9 , wherein the transition metal dichalcogenide film has a transition metal comprising one or more of tungsten (W), molybdenum (Mo), tantalum (Ta), titanium (Ti), or ruthenium (Ru).
11. The method of claim 9 , wherein the transition metal oxide precursor comprises one or more of WOF 4 , WO 2 F 2 , WOCl 4 , WO 2 Cl 2 , WOBr 4 , WO 2 Br 2 , WOI 4 , WO 2 I 2 , MoOF 4 , MoO 2 F 2 , MoOCl 4 , MoO 2 Cl 2 , MoOBr 4 , MoO 2 Br 2 , MoOI 4 , MoO 2 I 2 , TaOF 4 , TaO 2 F 2 , TaOCl 4 , TaO 2 Cl 2 , TaOBr 4 , TaO 2 Br 2 , TaOI 4 , TaO 2 I 2 , TiOF 4 , TiO 2 F 2 , TiOCl 4 , TiO 2 Cl 2 , TiOBr 4 , TiO 2 Br 2 , TiOI 4 , TiO 2 I 2 , RuOF 4 , RuO 2 F 2 , RuOCl 4 , RuO 2 Cl 2 , RuOBr 4 , RuO 2 Br 2 , RuOI 4 , and RuO 2 I 2 .
12. The method of claim 9 , wherein the transition metal dichalcogenide film is substantially free of oxygen.
13. The method of claim 9 , further comprising purging the substrate of the transition metal oxide precursor prior to exposing the substrate to the chalcogenide reactant.
14. The method of claim 13 , wherein purging comprises one or more of applying a vacuum or flowing a purge gas over the substrate, the purge gas comprising one or more of nitrogen (N 2 ), helium (He), and argon (Ar).
15. The method of claim 9 , wherein the chalcogenide reactant is selected from the group consisting of sulfur (S), selenium (Se), and tellurium (Te).
16. A method of depositing a film, the method comprising:
forming a transition metal oxide film in a transition metal oxide process cycle comprising sequential exposure of a substrate to a transition metal precursor, a purge gas, an oxide reactant comprising a plasma of one or more of O 2 or O 3 , and a purge gas; and
converting the transition metal oxide film to a transition metal dichalcogenide film in a chalcogen process cycle comprising sequential exposure of the transition metal oxide film to a chalcogenide reactant and a purge gas.
17. The method of claim 16 , wherein the chalcogen process cycle is performed after each metal oxide process cycle.
18. The method of claim 16 , wherein the transition metal oxide process cycle is repeated a number of times to form a transition metal oxide film of a predetermined thickness prior to performing the chalcogen process cycle.