Formation of SiOC thin films
Methods for depositing silicon oxycarbide (SiOC) 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 that does not comprise nitrogen and a second reactant that does not include oxygen. In some embodiments the methods allow for the deposition of SiOC films having improved acid-based wet etch resistance.
1. A method of forming a silicon oxycarbide (SiOC) thin film 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 that does not comprise nitrogen, wherein the vapor phase silicon precursor comprises bis(triethoxysilyl)ethane (BTESE) or 3-methoxypropyltrimethoxysilane (MPTMS);
contacting the surface of the substrate with at least one reactive species generated by plasma formed from a second reactant comprising hydrogen, wherein the second reactant does not comprise oxygen; and
optionally repeating the contacting steps until a SiOC film of a desired thickness has been formed.
2. The method of claim 1 , wherein a ratio of a wet etch rate of the SiOC thin film to a wet etch rate of thermal silicon oxide is less than about 5.
3. The method of claim 1 , wherein the SiOC thin film is deposited on a three-dimensional structure on the substrate.
4. The method of claim 3 , wherein a wet etch rate ratio of a wet etch rate of SiOC formed on a vertical surface of the three-dimensional structure to a wet etch rate of the SiOC formed on a horizontal surface of the three-dimensional structure is about 1:20 to about 20:1 in 0.5 wt % dilute HF.
5. The method of claim 1 , wherein the vapor phase silicon precursor does not comprise a halogen.
6. The method of claim 1 , wherein the reactive species comprises hydrogen plasma, hydrogen atoms, hydrogen radicals, or hydrogen ions.
7. The method of claim 6 , wherein the second reactant comprises H 2 .
8. The method of claim 1 , wherein the reactive species is generated from a second reactant comprising a noble gas.
9. The method of claim 1 , wherein the reactive species is generated from a second reactant comprising less than about 20 atomic % nitrogen.
10. The method of claim 1 , wherein the SiOC thin film comprises at least 20 at % oxygen.
11. The method of claim 1 , wherein the SiOC thin film comprises at least 0.1 at % carbon.
12. The method of claim 1 , wherein the SiOC thin film comprises less than about 10 at % nitrogen.
13. A method of forming a silicon oxycarbide (SiOC) thin film on a substrate in a reaction space comprising a plurality of deposition cycles, wherein at least one deposition cycle comprises:
alternately and sequentially contacting a surface of the substrate with a silicon precursor that does not comprise nitrogen and a second reactant comprising at least one reactive species comprising hydrogen, wherein the at least one reactive species is generated by plasma from a gas that does not comprise oxygen;
wherein the deposition cycle is repeated two or more times to form the SiOC thin film, and wherein the silicon precursor comprises bis(triethoxysilyl)ethane (BTESE) or 3-methoxypropyltrimethoxysilane (MPTMS).
14. The method of claim 13 , wherein the at least one reactive species is generated by plasma formed from a gas that does not comprise nitrogen.
15. The method of claim 13 , wherein a reactive species is generated by applying RF power of 5 Watts (W) to about 5000 W to the second reactant.
16. The method of claim 13 , wherein the deposition cycle is carried out at a process temperature of about 100° C. to about 300° C.
17. The method of claim 13 , wherein the deposition cycle is carried out at a process temperature of less than about 100° C.
18. The method of claim 13 , wherein the substrate comprises an organic material.
19. A method for depositing a silicon oxycarbide (SiOC) thin film on a substrate in a reaction space comprising:
contacting a surface of the substrate with a silicon precursor that does not comprise nitrogen, wherein the silicon precursor comprises bis(triethoxysilyl)ethane (BTESE) or 3-methoxypropyltrimethoxysilane (MPTMS);
exposing the substrate to a purge gas and/or vacuum to remove excess silicon precursor and reaction byproducts, if any;
contacting a surface of the substrate with a second reactant comprising hydrogen, wherein the second reactant comprises at least one reactive species generated by plasma from a gas that does not comprise oxygen;
exposing the substrate to a purge gas and/or vacuum to remove excess second reactant and reaction byproducts, if any;
repeating the contacting steps until a SiOC thin film of desired thickness has been formed.