High stress nitride film and method for formation thereof

• US 20060199357A1
• Filed: 03/06/2006
• Published: 09/07/2006
• Est. Priority Date: 03/07/2005
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Wan, Yuet Mei, Maes, Jan Willem, de Blank, Rene
• Granted Patent: US 7,629,267 B2
• Time in Patent Office: Days
• US Class Current: 438/482
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/45523 Pulsed gas flow or change of composition over time
• CPC Class Codes: H01L 21/02115 the material being carbon, e.g. alpha-C, diamond or hydrogen doped carbon
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/02321 introduction of substances into an already existing insulating layer H01L21/02227 and subgroups take precedence
• CPC Class Codes: H01L 21/3115 Doping the insulating layers
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 21/67017 Apparatus for fluid treatment H01L21/67126, H01L21/6715 take precedence
• CPC Class Codes: H01L 21/67115 mainly by radiation
• CPC Class Codes: H01L 29/7833 with lightly doped drain or source extension, e.g. LDD MOSFET's; DDD MOSFET's for thin film transistors H01L29/78618
• CPC Class Codes: H01L 29/7843 the means being an applied insulating layer

Abstract

A silicon nitride film is formed on a substrate in a reaction chamber by introducing trisilane and a reactive nitrogen species into the chamber in separate pulses. A carbon precursor gas is also flowed into the chamber during introduction of the trisilane and/or during introduction of the reactive nitrogen species, or in pulses separate from the trisilane and reactive nitrogen species pulses. The carbon is used as a dopant in the silicon nitride film and advantageously allows a high stress silicon nitride film to be formed.

Claims

1. A method of forming a silicon-containing compound layer, comprising:

loading a substrate into a reactor;

depositing a silicon layer on the substrate by exposing the substrate to a flow of trisilane;

interrupting the flow of trisilane;

forming an insulating silicon compound layer by exposing the silicon layer to a reactive nitrogen species while interrupting the flow of trisilane; and

exposing the substrate to a flow of a dopant precursor.

2. The method of claim 1, wherein the dopant precursor comprises a carbon species.

3. The method of claim 2, wherein the carbon species is one or more reactants chosen from the group consisting of mono-methyl silane, di-methyl silane, tri-methyl silane, tetra-methyl silane, mono-methyl disilane, di-methyl disilane, tri-methyl disilane, tetra-methyl disilane, mono-methyl trisilane, di-methyl trisilane, tri-methyl trisilane, tetra-methyl trisilane, methane, ethane, propane, butane and acetylene.

4. The method of claim 3, further comprising selecting the carbon species based upon a desired silicon-containing compound layer dopant concentration, wherein relatively high carbon content species are selected for relatively high desired dopant concentrations and relatively low carbon content species are selected for relatively low desired dopant concentrations.

5. The method of claim 1, wherein the dopant precursor comprises a germanium species.

6. The method of claim 1, wherein exposing the substrate to the flow of the dopant precursor is simultaneous with exposing the substrate to the flow of trisilane.

7. The method of claim 1, wherein exposing the substrate to the flow of the dopant precursor is simultaneous with exposing the silicon layer to the reactive nitrogen species.

8. The method of claim 1, wherein exposing the substrate to the flow of the dopant precursor comprises flowing the dopant precursor into the chamber in a pulse separate from exposing the silicon layer to the reactive nitrogen species or exposing the substrate to the flow of trisilane.

9. The method of claim 8, wherein depositing the silicon layer, interrupting the flow of trisilane, forming the silicon compound layer and exposing the substrate to the flow of the dopant precursor comprises repeatedly sequentially flowing trisilane, the reactive nitrogen species, the dopant precursor and the reactive nitrogen species into the chamber.

10. The method of claim 1, wherein exposing the silicon layer to a reactive nitrogen species comprises exposing the silicon layer to nitrogen radicals.

11. The method of claim 10, wherein exposing the silicon layer to nitrogen radicals comprises remotely activating nitrogen gas, and wherein exposing the silicon layer to a reactive nitrogen species further comprises exposing the silicon layer to ammonia.

12. The method of claim 1, wherein exposing the silicon layer to a reactive nitrogen species comprises exposing the silicon layer to ammonia.

13. The method of claim 1, wherein the reactive nitrogen species is a remotely generated excited nitrogen species.

14. The method of claim 1, wherein the reactor is a furnace configured to accommodate a plurality of substrates.

15. The method of claim 14, wherein depositing a silicon layer is performed under reaction kinetics limited conditions.

16. The method of claim 14, wherein depositing a silicon layer, interrupting the flow of trisilane, forming a silicon compound layer and exposing the substrate to a flow of a dopant precursor comprises accommodating each of the plurality of substrates in the furnace vertically spaced from one another with major surfaces of the substrate extending horizontally.

17. The method of claim 1, wherein depositing the silicon layer, interrupting the flow of trisilane, forming the silicon compound layer and exposing the substrate to the flow of the dopant precursor comprises maintaining the substrate at a temperature between about 250°

C. and about 600°

C.

18. The method of claim 17, wherein the temperature is between about 300°

C. and about 500°

C.

19. The method of claim 1, wherein exposing the substrate to a flow of trisilane comprises flowing trisilane to the reactor at a rate less than about 400.1 mg/minute.

20. An integrated circuit, comprising:

a silicon nitride film comprising a dopant, wherein a tensile stress of the film is about 2 GPa or greater.

21. The integrated circuit of claim 20, wherein the film is a gate stack liner for a transistor.

22. The integrated circuit of claim 20, wherein the dopant comprises carbon.

23. The integrated circuit of claim 20, wherein the film is formed by:

separately exposing a substrate to a silicon precursor and a reactive nitrogen species; and

exposing the substrate to a dopant precursor.

24. The integrated circuit of claim 23, wherein the silicon precursor is trisilane.

25. The integrated circuit of claim 23, wherein the dopant precursor is a carbon species.

26. The integrated circuit of claim 20, wherein the film has a thickness of between about 100 Å

and about 2000 Å

.

27. A method of semiconductor processing, comprising:

repeatedly separately exposing a substrate to a silane and a first reactive species to form a silicon-containing film; and

increasing a tensile stress of the silicon-containing film by exposing the substrate to a second reactive species.

28. The method of claim 27, wherein the film has a tensile stress of greater than 1.1 GPa.

29. The method of claim 28, wherein the film has a tensile stress of about 2 GPa or greater.

30. The method of claim 27, wherein the silane is chosen from the group consisting of chemicals having the molecular formula SiH_4-nCl_n, where n=1 to 4, and Si_nH_2n+2, where n=1 to 4.

31. The method of claim 30, wherein the first reactive species is a reactive nitrogen species and the silicon-containing film is a silicon nitride film.

32. The method of claim 31, wherein the second reactive species is a carbon species.

33. The method of claim 32, wherein exposing the substrate to the second reactive species is performed concurrently with exposing the substrate to the silane or with exposing the substrate to the first reactive.

34. The method of claim 27, wherein exposing the substrate to the silane non-self-limitingly deposits a silicon layer.

35. The method of claim 27, wherein exposing the substrate to the second reactive species is separate from exposing the substrate to the silane or to the first reactive species.

36. The method of claim 27, wherein repeatedly separately exposing the substrate to the silane and the first reactive species and exposing the substrate to a second reactive species forms a liner layer over a transistor gate stack.

37. The method of claim 27, further comprising using the silicon-containing film as an etch stop barrier after exposing the substrate to the second reactive species.