Methods for making silicon and nitrogen containing films

1. A method for forming a silicon and nitrogen containing film having a dielectric constant (k) of about 7 or less, an oxygen content of about 5 at. % or less and a carbon content less than 5 at. % via a plasma enhanced ALD process, the method comprising:

a) providing a substrate comprising a surface feature in a reactor;

b) heating the reactor to one or more temperatures ranging up to about 600° C. and optionally, maintaining the reactor at a pressure of 100 torr or less;

c) introducing into the reactor at least one silicon precursor having two Si—C—Si linkages and selected from a group consisting of 1-chloro-1,3-disilacyclobutane, 1-bromo-1,3-disilacyclobutane, 1,3-dichloro-1,3-1,3-disilacyclobutane, 1,3-dibromo-1,3-disilacyclobutane, 1,1,3-trichloro-1,3-disilacyclobutane, 1,1,3-tribromo-1,3-disilacyclobutane, 1,1,3,3-tetrachloro-1,3-disilacyclobutane, 1,1,3,3-tetrabromo-1,3-disilacyclobutane, 1,3-dichloro-1,3-dimethyl-1,3-disilacyclobutane, 1,3-bromo-1,3-dimethyl-1,3-disilacyclobutane, 1,1,1,3,3,5,5,5-octachloro-1,3,5-trisilapentane, 1,1,3,3,5,5-hexachloro-1,5-dimethyl-1,3,5-trisilapentane, 1,1,1,5,5,5-hexachloro-3,3-dimethyl-1,3,5-trisilapentane, 1,1,3,5,5-pentachloro-1,3,5-trimethyl-1,3,5-trisilapentane, 1,1,1,5,5,5-hexachloro-1,3,5-trisilapentane, 1,1,5,5-tetrachloro-1,3,5-trisilapentane, 1-iodo-1,3-disilacyclobutane, 1,1-diiodo-1,3-disilacyclobutane, 1,3-diiodo-1,3-disilacyclobutane, 1,1,3-triiodo-1,3-disilacyclobutane, 1,1,3,3-tetraiodo-1,3-disilacyclobutane, and 1,3-diiodo-1,3-dimethyl-1,3-disilacyclobutane to form a silicon-containing species on the substrate;

d) purging the reactor of any unreacted silicon precursors and/or any reaction by-products from step c, using a first inert gas;

e) providing a plasma comprising an ammonia source into the reactor to react with the silicon-containing species to form a silicon nitride film;

f) purging the reactor of any further reaction by-products from step e with a second inert gas; and

g) repeating steps c to f as necessary to bring the silicon nitride film to a predetermined thickness.

2. The method according to claim 1 , further comprising:

treating the silicon nitride film with a spike anneal at a temperature ranging between 400 and 1000° C.

3. The method according to claim 1 , further comprising:

exposing the silicon nitride film to a UV light source either during or after deposition of the silicon nitride film.

4. The method according to claim 1 , further comprising:

exposing the silicon nitride film to a plasma comprising hydrogen or inert gas or nitrogen.

5. The method of claim 1 further comprising performing a thermal anneal on the silicon nitride film at temperatures from 300° C. to 1000° C.

6. The method of claim 1 further comprising performing a plasma treatment on the silicon nitride film with an inert gas plasma or hydrogen/inert plasma or nitrogen plasma at a temperature ranging between 25° C. and 600° C.

7. The method of claim 1 further comprising:

h) providing a plasma comprising a nitrogen source into the reactor to react with the silicon-containing species and further form the silicon nitride film; and

i) purging the reactor of any further reaction by-products with a second inert gas, wherein the step g) of repeating steps c to f also includes repeating steps h and i such that steps c to i repeated as necessary to bring the silicon nitride film to a predetermined thickness.

8. A film formed according to the method of claim 7 , the film having a density of about 2.7 g/cm 3 or higher.

9. The method according to claim 1 , wherein the silicon nitride film is a carbon-doped silicon nitride film.

10. The method of claim 9 further comprising performing a thermal anneal on the carbon doped silicon nitride film at temperatures from 300° C. to 1000° C.

11. The method of claim 9 further comprising performing a plasma treatment on the carbon-doped silicon nitride film with an inert gas plasma or hydrogen/inert plasma or nitrogen plasma at a temperature ranging between 25° C. and 600° C.

12. The film according to claim 1 having a carbon content of about 3 atomic weight percent or less as measured by X-ray photoelectron spectroscopy.

13. The film according to claim 12 having a carbon content of about 2 atomic weight percent or less as measured by X-ray photoelectron spectroscopy.

14. The film according to claim 13 having a carbon content of about 1 atomic weight percent or less as measured by X-ray photoelectron spectroscopy.

15. The method according to claim 1 , further comprising:

treating the silicon nitride film with an oxygen source at one or more temperatures ranging from ambient temperature to 1000° C. to convert the silicon nitride into a silicon oxynitride film, either in situ or in a separate chamber from the reactor.

16. The method of claim 15 further comprising performing a plasma treatment on the silicon oxynitride film with an inert gas plasma or hydrogen/inert plasma or nitrogen plasma at a temperature ranging between 25° C. and 600° C.

17. The method according to claim 15 , wherein the silicon nitride film is a carbon-doped silicon nitride film, and wherein the step of treating with an oxygen source converts the carbon-doped silicon nitride into a carbon-doped silicon oxynitride film.

18. The method of claim 17 further comprising performing a plasma treatment on the carbon-doped silicon oxynitride film with an inert gas plasma or hydrogen/inert plasma or nitrogen plasma at a temperature ranging between 25° C. and 600° C.