Formation of SiOCN thin films
Methods for depositing silicon oxycarbonitride (SiOCN) thin films on a substrate in a reaction space are provided. The methods can include at least one plasma enhanced atomic layer deposition (PEALD) cycle including alternately and sequentially contacting the substrate with a silicon precursor and a second reactant that does not include oxygen. In some embodiments the methods allow for the deposition of SiOCN films having improved acid-based wet etch resistance.
1. A method of forming a thin film comprising Si—O bonds on a substrate in a reaction space by a plasma enhanced atomic layer deposition (PEALD) process, wherein the PEALD process comprises at least one deposition cycle comprising:
contacting a surface of the substrate with a vapor phase silicon precursor to thereby adsorb a silicon species on the surface of the substrate; and
contacting the adsorbed silicon species with at least one reactive species generated by plasma formed from gas that does not comprise oxygen, wherein the adsorbed silicon species is not contacted with oxygen-containing reactive species generated from gas; and
repeating the contacting steps until the thin film has been formed,
wherein the silicon precursor comprises a silicon atom and a ligand comprising an amino or alkylamino group,
wherein the silicon atom is bonded to oxygen,
wherein at least one alkyl group is attached to the silicon atom, and
wherein the silicon precursor does not comprise a halogen.
2. The method of claim 1 , wherein the silicon precursor comprises at least one —NH 2 group attached to a carbon chain.
3. The method of claim 1 , wherein the silicon precursor comprises at least one alkylamino ligand.
4. The method of claim 1 , wherein the silicon precursor comprises an alkoxide group bonded to the silicon atom.
5. The method of claim 1 , wherein the silicon precursor comprises at least one hydrogen bonded to silicon.
6. The method of claim 1 , wherein the thin film comprises up to 10 at % nitrogen.
7. The method of claim 6 , wherein the thin comprises more than 5 at % nitrogen.
8. The method of claim 6 , wherein the thin film comprises more than 1 at % nitrogen.
9. The method of claim 1 , wherein the thin film comprises at least 20 at % oxygen.
10. The method of claim 1 , wherein the thin film comprises from about 0.5 to about 40 at % carbon.
11. The method of claim 10 , wherein the thin film comprises at least 5 at % carbon.
12. The method of claim 1 , wherein a ratio of a wet etch rate of the thin film to a wet etch rate of thermal silicon oxide is less than about 5.
13. The method of claim 1 , wherein a ratio of a wet etch rate of the thin film to a wet etch rate of thermal silicon oxide is less than about 0.3.
14. The method of claim 1 , wherein the thin film is deposited on a three-dimensional structure.
15. The method of claim 14 , wherein a wet etch rate ratio of a wet etch rate of the thin film formed on a top surface of the three-dimensional structure to a wet etch rate of the thin film formed on a sidewall surface of the three-dimensional structure is about 1:1 in dilute HF.
16. The method of claim 1 , wherein the reactive species comprises hydrogen plasma, hydrogen atoms, hydrogen radicals, or hydrogen ions.
17. The method of claim 16 , wherein the reactive species further comprises nitrogen plasma, nitrogen atoms, nitrogen radicals, or nitrogen ions.
18. The method of claim 1 , wherein the reactive species is generated from a second reactant comprising a noble gas.
19. The method of claim 1 , wherein the reactive species is generated by plasma from a second reactant comprising hydrogen.
20. The method of claim 19 , wherein the second reactant comprises H 2 .
21. The method of claim 1 , wherein the substrate comprises an organic material.