Methods for deposition of silicon carbide and silicon carbonitride films
Methods for deposition of silicon carbide films on a substrate surface are provided. The methods include the use of vapor phase carbosilane precursors and may employ plasma enhanced atomic layer deposition processes. The methods may be carried out at temperatures less than 600° C., for example between about 23° C. and about 200° C. or at about 100° C. This silicon carbide layer may then be densified to remove hydrogen content. Additionally, the silicon carbide layer may be exposed to a nitrogen source to provide reactive N—H groups, which can then be used to continue film deposition using other methods. Plasma processing conditions can be used to adjust the carbon, hydrogen and/or nitrogen content of the films.
1. A method for forming a silicon carbide film on a substrate surface comprising exposing a substrate having a reactive surface to a vapor phase carbosilane precursor to form a silicon carbide layer on the substrate surface, wherein the carbosilane precursor contains at least one carbon atom bridging at least two silicon atoms; and treating the silicon carbide layer with a plasma effective to remove hydrogen.
2. The method of claim 1 wherein the carbosilane precursor is 1,3-disilapropane, 1,3-disilabutane, 1,3-disilacyclobutane, 1,3,5-trisilacyclohexane, 1,3,5-tisilahexane, 1,3,5-trisilapentane, 1,3,5,7-tetrasilaheptane, and 2,4,6-trisilaheptane.
3. The method of claim 1 , wherein the reactive surface is produced by plasma treatment of the substrate.
4. The method of claim 1 , wherein the substrate is exposed to the vapor phase carbosilane precursor at a temperature of less than 600° C.
5. The method of claim 4 , wherein the substrate is exposed to the vapor phase carbosilane precursor at a temperature between about 23° C. and about 200° C.
6. The method of claim 1 , further comprising treating the silicon carbide layer on the substrate surface with a plasma to activate the silicon carbide layer and exposing the activated silicon carbide layer to a second vapor phase carbosilane precursor to form an additional silicon carbide layer on the substrate surface.
7. The method of claim 6 , wherein the second vapor phase silicon carbide is different from the silicon carbide in the activated silicon carbide layer.
8. A method of forming a layer on a substrate surface, the method comprising:
exposing the substrate surface to a carbosilane precursor containing at least one carbon atom bridging at least two silicon atoms;
exposing the carbosilane precursor to a low-power energy source to provide a carbosilane at the substrate surface, wherein the carbosilane precursor is exposed to the low-power plasma for about 0.10 seconds to about 5.0 seconds;
densifying the carbosilane; and
exposing the carbosilane surface to a nitrogen source.
9. The method of claim 8 , wherein densifying the carbosilane comprises exposing the substrate surface to a plasma containing one or more of He, Ar and H 2 .
10. The method of claim 8 , wherein the carbosilane precursor contains a methylene group bridging at least two silicon atoms.
11. The method of claim 10 , wherein the carbosilane precursor is one or more of 1,3-disilapropane, 1,3-disilabutane, 1,3-disilacyclobutane, 1,3,5-trisilacyclohexane, 1,3,5-tisilahexane, 1,3,5-trisilapentane, 1,3,5,7-tetrasilaheptane, and 2,4,6-trisilaheptane.
12. The method of claim 8 , wherein exposing the carbosilane to a nitrogen source comprises flowing ammonia or exposing the carbosilane to a plasma containing nitrogen.
13. The method of 12 , wherein exposing the carbosilane to a plasma containing nitrogen results in the formation of N—H bonds that promote irreversible attachment of a monolayer of the carbosilane to the substrate surface.
14. The method of claim 8 , wherein exposing the carbosilane precursor to a low-power energy source comprises exposing the carbosilane precursor to a low-power plasma, ultraviolet radiation, electron beam or ion beam.
15. The method of claim 8 wherein the low-power plasma has a value of about 10 W to about 200 W.