Molecular layer deposition of silicon carbide
Molecular layer deposition of silicon carbide is described. A deposition precursor includes a precursor molecule which contains silicon, carbon and hydrogen. Exposure of a surface to the precursor molecule results in self-limited growth of a single layer. Though the growth is self-limited, the thickness deposited during each cycle of molecular layer deposition involves multiple “atomic” layers and so each cycle may deposit thicknesses greater than typically found during atomic layer depositions. Precursor effluents are removed from the substrate processing region and then the surface is irradiated before exposing the layer to the deposition precursor again.
1. A method of forming a silicon carbide layer on a surface of a substrate positioned in a substrate processing region, the method comprising:
at least three sequential steps comprising:
(i) irradiating the surface of the substrate,
(ii) exposing the surface to a silicon-carbon-and-hydrogen-containing precursor comprising a silicon-carbon-and-hydrogen-containing molecule, wherein the silicon-carbon-and-hydrogen-containing molecule has at least two Si—C single-bonds, wherein exposing the surface to a silicon-carbon-and-hydrogen-containing precursor results in growth of a single molecular layer of silicon carbide, and
(iii) removing process effluents including unreacted silicon-carbon-and-hydrogen-containing precursor from the substrate processing region.
2. The method of claim 1 , further comprising repeating the at least three sequential steps again until the silicon carbide layer reaches a target thickness.
3. The method of claim 1 , wherein irradiating the surface comprises shining UV light at the surface of the substrate.
4. The method of claim 1 , wherein irradiating the surface comprises flowing gas into and striking a plasma within the substrate processing region.
5. The method of claim 1 , wherein exposing the surface to a silicon-carbon-and-hydrogen-containing precursor results in self-limiting growth of the single-molecular layer of silicon carbide.
6. The method of claim 1 , wherein an iteration of steps (i)-(iii) deposits between 0.5 nm and 6 nm of silicon carbide on the substrate.
7. The method of claim 1 , wherein the silicon-carbon-and-hydrogen-containing molecule comprises a carbon-carbon double-bond.
8. The method of claim 1 , wherein the silicon-carbon-and-hydrogen-containing molecule comprises a protective group which makes the growth of the single molecular layer of silicon carbide self-limiting yet allows removal of the protective group through irradiation of the surface.
9. The method of claim 8 , wherein the protective group comprises a silicon atom bonded to another silicon atom within the silicon-carbon-and-hydrogen-containing molecule.
10. The method of claim 8 , wherein the protective group comprises Si(CH 3 ) 3 .
11. The method of claim 1 , wherein the silicon-carbon-and-hydrogen-containing molecule comprises one of the following molecules with one or more protective groups bonded to a silicon atom in place of a terminal H or Me group
12. The method of claim 1 , wherein the silicon carbide layer is essentially devoid of oxygen.
13. The method of claim 1 , wherein the silicon-carbon-and-hydrogen-containing molecule is essentially devoid of oxygen.
14. The method of claim 1 , wherein the silicon-carbon-and-hydrogen-containing molecule comprises oxygen but the silicon carbide layer is essentially devoid of oxygen.
15. The method of claim 1 , wherein the step of irradiating the surface comprises cleaving an Si—Si bond.
16. The method of claim 1 , wherein the step of irradiating the surface comprises removing a protective chemical group from the surface.
17. The method of claim 16 , wherein the step of irradiating the surface comprises removing more than one protective chemical group from the surface.
18. The method of claim 1 , further comprising treating the surface to reduce the hydrogen content in the silicon carbide layer after the silicon carbide is deposited.