METHOD TO FORM ULTRA HIGH QUALITY SILICON-CONTAINING COMPOUND LAYERS

• US 20090311857A1
• Filed: 08/24/2009
• Published: 12/17/2009
• Est. Priority Date: 07/19/2002
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Weeks, Keith D., Pomarede, Christophe F., Werkhoven, Christiaan J., Todd, Michael A.
• Granted Patent: US 7,964,513 B2
• Time in Patent Office: Days
• US Class Current: 438/591
• CPC Class Codes: C23C 16/24 Deposition of silicon only
• 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: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• 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 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02247 formation by nitridation, e.g. nitridation of the substrate
• CPC Class Codes: H01L 21/02252 formation by plasma treatment, e.g. plasma oxidation of the substrate after treatment of an insulating film by plasma H01L21/3105 and subgroups
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/3144 on silicon
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/31662 of silicon in uncombined form
• CPC Class Codes: H01L 21/3185 of siliconnitrides

Abstract

Multiple sequential processes are conducted in a reaction chamber to form ultra high quality silicon-containing compound layers, including silicon nitride layers. In a preferred embodiment, a silicon layer is deposited on a substrate using trisilane as the silicon precursor. A silicon nitride layer is then formed by nitriding the silicon layer. By repeating these steps, a silicon nitride layer of a desired thickness is formed.

Claims

1. A method for semiconductor processing, comprising:

providing a substrate in a deposition chamber;

depositing a film of an insulating silicon compound on the substrate by performing a plurality of chemical vapor deposition cycles, each cycle comprising;

pyrollizing a silicon source with a substrate to form a silicon film, wherein the silicon source pyrollizes upon contact with the substrate, and wherein the silicon source for forming a first silicon film on the substrate, in a first performance of a cycle of the plurality of cycles, is trisilane; and

subsequently reacting the silicon film to form the insulating silicon compound,

wherein the film of the insulating silicon compound formed by performing the plurality of deposition cycles has a thickness non-uniformity of about 5% or less and a step coverage of about 80% or greater.

2. The method of claim 1, wherein reacting the silicon film comprises nitriding the silicon film.

3. The method of claim 2, wherein nitriding the silicon film comprises exposing the silicon film to atomic nitrogen.

4. The method of claim 2, wherein the first silicon film has a thickness of at least about a nitridation saturation depth.

5. The method of claim 1, further comprising increasing a deposition temperature after depositing the first silicon film.

6. The method of claim 1, further comprising replacing trisilane with a halosilane after the first silicon film is formed.

7. The method of claim 1, further comprising replacing trisilane with a compound having a chemical formula Si_nH_2n+2, wherein n is equal to a number from 1 to 4, after the first silicon film is formed.

8. The method of claim 1, further comprising increasing a thickness of the film of the insulating silicon compound by depositing an additional silicon compound film on the film of the insulating silicon compound, the additional silicon compound film formed by simultaneously introducing mutually reactive precursors into the reaction chamber.

9. The method of claim 8, wherein the film of the insulating silicon compound and the additional silicon compound film comprise silicon nitride.

10. The method of claim 9, further comprising forming a silicon compound sealing layer directly over the additional silicon compound film, wherein forming the silicon compound sealing layer comprises:

forming a silicon layer over the additional silicon compound layer by exposing the substrate to a silicon source comprising trisilane; and

reacting the silicon layer.

11. The method of claim 10, wherein the silicon compound sealing layer comprises silicon nitride.

12. The method of claim 1, wherein depositing the film of the insulating silicon compound is performed in a single substrate reaction chamber.

13. The method of claim 1, wherein the reaction chamber is a laminar flow reaction chamber.

14. A process for semiconductor processing, comprising:

decomposing trisilane to form a silicon layer on a crystalline surface of a semiconductor substrate under mass transport limited conditions; and

subsequently nitriding the silicon layer to form a silicon nitride layer,

wherein the silicon nitride layer has a thickness non-uniformity of about 5% or less and a step coverage of about 80% or greater.

15. The process of claim 14, wherein a hydrogen concentration of the silicon nitride layer is less than about 0.2 atomic percent.

16. The process of claim 14, further comprising repeating decomposing trisilane and nitriding the silicon layer until a silicon nitride layer of between about 3 Å

and 1000 Å

thick results.

17. The process of claim 14, further comprising forming a gate electrode over the silicon nitride layer.

18. A method of thermal chemical vapor deposition, comprising:

thermally decomposing a silicon precursor on a substrate under mass transport limited conditions to form a silicon layer, the silicon layer having a thickness non-uniformity of about 5% or less and a step coverage of about 80% or greater, wherein a height of a top surface of the silicon layer over the substrate is greater than about a nitridation saturation depth;

nitriding the silicon layer; and

sequentially repeating thermally decomposing the silicon precursor and nitriding the silicon layer to form a silicon nitride layer of a desired thickness.

19. The method of claim 18, wherein thermally decomposing the silicon precursor and nitriding the silicon layer are performed at a deposition pressure of less than about 100 Torr.

20. The method of claim 18, wherein thermally decomposing the silicon precursor and nitriding the silicon layer forms a gate dielectric.