Method for producing gate stack sidewall spacers

• US 7,253,123 B2
• Filed: 01/10/2005
• Issued: 08/07/2007
• Est. Priority Date: 01/10/2005
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Xia, Li-Qun, Arghavani, Reza, Yim, Kang Sub, Kwan, Michael Chiu
• Primary Examiner(s): Everhart; Caridad
• Application Number:
  US11/032,859
• Publication Number:
  US 20060154493A1
• Time in Patent Office: 939 Days
• Field of Search: 257/E21.17, 257/E21.478, 427/255.27, 427/255.28, 438/786, 438/788
• US Class Current: 438/786
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02167 the material being a silicon carbide not containing oxygen, e.g. SiC, SiC:H or silicon carbonitrides H01L21/02126 and H01L21/0214 take precedence
• 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 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02329 introduction of nitrogen
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/3148 Silicon Carbide layers
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 29/4983 with a lateral structure, e.g. a Polysilicon gate with a lateral doping variation or with a lateral composition variation or characterised by the sidewalls being composed of conductive, resistive or dielectric material
• CPC Class Codes: H01L 29/6659 with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET

Abstract

A method for forming sidewall spacers on a gate stack by depositing one or more layers of silicon containing materials using PECVD process(es) on a gate structure to produce a spacer having an overall k value of about 3.0 to about 5.0. The silicon containing materials may be silicon carbide, oxygen doped silicon carbide, nitrogen doped silicon carbide, carbon doped silicon nitride, nitrogen doped silicon oxycarbide, or combinations thereof. The deposition is performed in a plasma enhanced chemical vapor deposition chamber and the deposition temperature is less than 450° C. The sidewall spacers so produced provide good capacity resistance, as well as excellent structural stability and hermeticity.

Claims

1. A method for forming a sidewall spacer for a gate electrode, comprising:

placing a substrate having a gate structure in a plasma process chamber;

flowing process gas(es) into the plasma process chamber;

creating a plasma in the plasma process chamber; and

depositing one or more layers of silicon containing materials on the gate structure at a temperature equal to or less than 450°

C. in the presence of the plasma, wherein the one or more layers of silicon containing materials have an overall dielectric constant value of about 3.0 to about 5.0 and comprise materials selected from the group consisting of silicon carbide, oxygen doped silicon carbide, nitrogen doped silicon carbide, carbon doped silicon nitride, nitrogen doped silicon oxycarbide, and combinations thereof.

2. The method of claim 1, wherein the sidewall spacer is formed as a single layer.

3. The method of claim 1 wherein the sidewall spacer comprises silicon carbide.

4. The method of claim 3, wherein the dielectric constant of the silicon carbide is varied by changing a ratio of mixed frequency power of the plasma process chamber during deposition.

5. The method of claim 3, wherein the dielectric constant of the silicon carbide is varied by changing a gas mixture used to deposit the silicon carbide.

6. The method of claim 1, wherein the silicon containing materials comprise oxygen doped silicon carbide.

7. The method of claim 6, wherein the dielectric constant of the oxygen doped silicon carbide is varied by changing a ratio of mixed frequency power to the plasma process chamber.

8. The method of claim 6, wherein the dielectric constant of the oxygen doped silicon carbide is varied by changing the process gases or process gas flow rates.

9. The method of claim 6, wherein the dielectric constant of the oxygen doped silicon carbide is varied by changing the deposition temperature.

10. The method of claim 1, wherein the silicon containing materials comprise nitrogen doped silicon carbide.

11. The method of claim 10, wherein the nitrogen doped silicon carbide has a nitrogen content of less than about 30 atomic percent.

12. The method of claim 10, wherein the dielectric constant of the nitrogen doped silicon carbide is increased by increasing RF power.

13. The method of claim 12, wherein the dielectric constant of the nitrogen doped silicon carbide is varied by adjusting a nitrogen source used during deposition and/or a concentration of the nitrogen source in a deposition gas mixture.

14. The method of claim 1, wherein the silicon containing materials comprise nitrogen doped silicon carbide and the nitrogen doped silicon carbide is formed by plasma nitridation of silicon carbide.

15. The method of claim 14, wherein the nitrogen doped silicon carbide has a nitrogen content of less than about 30 atomic percent.

16. The method of claim 14, wherein the plasma nitridation is performed at a temperature between about 100°

C. to about 450°

C.

17. The method of claim 1, wherein the silicon containing materials comprise carbon doped silicon nitride.

18. The method of claim 17, wherein the carbon doped silicon nitride has a carbon content of less than about 30 atomic percent.

19. The method of claim 17, wherein the dielectric constant of the carbon doped silicon nitride is varied by adjusting a reaction pressure, a nitrogen source used during deposition and a concentration of gases in a deposition gas mixture.

20. The method of claim 1, wherein the silicon containing materials comprise carbon doped silicon oxynitride.

21. The method of claim 20, wherein the dielectric constant of the carbon doped silicon oxynitride is varied by adjusting a deposition temperature.

22. The method of claim 20, wherein the dielectric constant of the carbon doped silicon oxynitride is varied by adjusting reactants used to form the carbon doped silicon oxynitride.

23. A method for forming a sidewall spacer for a gate electrode, comprising:

placing a substrate having a gate structure in a plasma process chamber;

flowing process gas(es) into the plasma process chamber;

creating a plasma in the plasma process chamber; and

depositing one or more layers of silicon containing materials on the gate structure in the presence of the plasma, wherein the one or more layers of silicon containing materials have an overall dielectric constant value of about 3.0 to about 5.0, and the one or more layers of silicon containing materials are selected from the group consisting of silicon carbide, oxygen doped silicon carbide, nitrogen doped silicon carbide, carbon doped silicon nitride, nitrogen doped silicon oxycarbide, and combinations thereof.

24. A method for forming a sidewall spacer for a gate electrode, comprising:

placing a substrate having a gate structure in a plasma process chamber;

flowing process gas(es) into the plasma process chamber;

creating a plasma in the plasma process chamber; and

depositing one or more layers of silicon containing materials on the gate structure at a temperature equaling to or below 450°

C. in the presence of the plasma, wherein the one or more layers of silicon containing materials have an overall dielectric constant value of about 3.0 to about 5.0, and the one or more layers of silicon containing materials are selected from the group consisting of silicon carbide, oxygen doped silicon carbide, nitrogen doped silicon carbide, carbon doped silicon nitride, nitrogen doped silicon oxycarbide, and combinations thereof.