Methods of depositing electrically active doped crystalline Si-containing films
View Patent ↗Methods of making Si-containing films that contain relatively high levels of Group III or Group V dopants involve chemical vapor deposition using trisilane and a dopant precursor. Extremely high levels of substitutional incorporation may be obtained, including crystalline silicon films that contain at least about 3×10 20 atoms cm −3 of an electrically active dopant. Substitutionally doped Si-containing films may be selectively deposited onto the crystalline surfaces of mixed substrates by introducing an etchant gas during deposition.
1. A method of depositing a doped crystalline Si-containing film, comprising:
providing a substrate disposed within a chamber;
intermixing trisilane and a dopant precursor to form a feed gas, the dopant precursor comprising an electrical dopant;
contacting the substrate with the feed gas under chemical vapor deposition conditions; and
depositing a doped crystalline Si-containing film onto the substrate at a deposition rate of at least about 10 nm per minute, the doped crystalline Si-containing film having an as-deposited resistivity of about 1.0 mΩ·cm or less prior to any activation anneal, wherein the doped crystalline Si-containing film contains less than about 3×10 19 atoms cm −3 of an electrically inactive dopant.
2. The method of claim 1 , wherein the electrical dopant is an n-type dopant.
3. The method of claim 2 , wherein the electrical dopant comprises arsenic.
4. The method of claim 2 , wherein the electrical dopant comprises phosphorous.
5. The method of claim 1 , wherein the electrical dopant is a p-type dopant.
6. The method of claim 5 , wherein the electrical dopant comprises boron.
7. The method of claim 1 , further comprising intermixing a carbon source with the trisilane and the dopant precursor to form the feed gas.
8. The method of claim 7 , wherein the carbon source is selected from the group consisting of monosilylmethane, disilylmethane, trisilylmethane, tetrasilylmethane, monomethyl silane, dimethyl silane and 1,3-disilabutane.
9. The method of claim 7 , wherein the carbon source comprises monomethylsilane and the dopant precursor comprises arsenic.
10. The method of claims 7 , wherein the carbon source comprises monomethylsilane and the dopant precursor comprises phosphorous.
11. The method of claim 1 , further comprising intermixing a germanium source with the trisilane and the dopant precursor to form the feed gas.
12. The method of claim 11 , wherein the germanium source comprises germane.
13. The method of claim 1 , wherein the deposition rate is at least about 20 nm per minute.
14. The method of claim 1 , further comprising introducing the feed gas to the chamber.
15. The method of claim 1 , wherein the doped crystalline Si-containing film comprises at least about 3×10 20 atoms cm −3 of the electrical dopant.
16. The method of claim 1 , wherein the doped crystalline Si-containing film comprises at least about 4×10 20 atoms cm −3 of the electrical dopant.
17. The method of claim 1 , wherein the doped crystalline Si-containing film contains less than about 5×10 20 atoms cm −3 of an electrical dopant.
18. The method of claim 1 , wherein the doped crystalline Si-containing film contains less than about 2×10 19 atoms cm −3 of an electrical inactive dopant.
19. The method of claim 1 , wherein the doped crystalline Si-containing film contains less than about 1×10 19 atoms cm −3 of an electrically inactive dopant.
20. The method of claim 1 , wherein the doped crystalline Si-containing film has a resistivity of about 0.7 mΩ·cm or less.
21. The method of claim 1 , wherein the doped crystalline Si-containing film has a resistivity of about 0.5 mΩ·cm or less.
22. The method of claim 1 , wherein the doped crystalline Si-containing film has a resistivity of about 0.4 mΩ·cm or less.
23. The method of claim 1 , wherein the dopant precursor comprises a dopant hydride.
24. The method of claim 23 , wherein the dopant hydride is a p-type dopant hydride selected from diborane or deuterated diborane.
25. The method of claim 23 , wherein the dopant hydride is a n-type dopant hydride selected from phosphine, arsenic vapor or arsine.