Method for integrating a high-k gate dielectric in a transistor fabrication process

• US 20050101147A1
• Filed: 11/08/2003
• Published: 05/12/2005
• Est. Priority Date: 11/08/2003
• Status: Abandoned Application

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Jeon, Joong S., Ang, Boon-Yong, Xiang, Qi, Labelle, Catherine B., Zhong, Huicai, Holbrook, Allison K.
• Application Number:
  US10/705,347
• Publication Number:
  US 20050101147A1
• Time in Patent Office: Days
• US Class Current: 438/710
• CPC Class Codes: H01L 21/28176 with a treatment, e.g. annealing, after the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28202 in a nitrogen-containing ambient, e.g. nitride deposition, growth, oxynitridation, NH3 nitridation, N2O oxidation, thermal nitridation, RTN, plasma nitridation, RPN
• CPC Class Codes: H01L 21/28247 passivation or protection of the electrode, e.g. using re-oxidation
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material

Abstract

According to one exemplary embodiment, a method for forming a field-effect transistor on a substrate, where the substrate includes a high-k dielectric layer situated over the substrate and a gate electrode layer situated over the high-k dielectric layer, comprises a step of etching the gate electrode layer and the high-k dielectric layer to form a gate stack, where the gate stack comprises a high-k dielectric segment situated over the substrate and a gate electrode segment situated over the high-k dielectric segment. According to this exemplary embodiment, the method further comprises performing a nitridation process on the gate stack. The nitridation process can be performed by, for example, utilizing a plasma to nitridate sidewalls of the gate stack, where the plasma comprises nitrogen. The nitridation process can cause nitrogen to enter the high-k dielectric segment and form an oxygen diffusion barrier in the high-k dielectric segment, for example.

Claims

1. A method for forming a field-effect transistor on a substrate, said substrate including a high-k dielectric layer situated over said substrate and a gate electrode layer situated over said high-k dielectric layer, said method comprising steps of:

etching said gate electrode layer and said high-k dielectric layer to form a gate stack, said gate stack comprising a high-k dielectric segment situated over said substrate and a gate electrode segment situated over said high-k dielectric segment;

performing a nitridation process on said gate stack.

2. The method of claim 1 wherein said step of performing said nitridation process on said gate stack comprises utilizing a plasma to nitridate sidewalls of said gate stack, said plasma comprising nitrogen.

3. The method of claim 1 wherein said step of performing said nitridation process on said gate stack causes nitrogen to enter said high-k dielectric segment, said nitrogen forming an oxygen diffusion barrier in said high-k dielectric segment.

4. The method of claim 1 wherein said step of etching said gate electrode layer and said high-k dielectric layer to form said gate stack is performed in a process chamber, said process chamber being utilized to perform said step of performing said nitridation process on said gate stack.

5. The method of claim 1 wherein said step of etching said gate electrode layer and said high-k dielectric layer to form said gate stack is performed in a first process chamber and said step of performing said nitridation process on said gate stack is performed in a second process chamber.

6. The method of claim 1 wherein said high-k dielectric segment is selected from the group consisting of hafnium oxide, hafnium silicate, zirconium oxide, zirconium silicate, and aluminum oxide.

7. The method of claim 1 wherein said gate electrode segment comprises polysilicon.

8. A method for forming a field-effect transistor on a substrate, said substrate including a high-k dielectric layer situated over said substrate and a gate electrode layer situated over said high-k dielectric layer, said method comprising a step of etching said gate electrode layer and said high-k dielectric layer to form a gate stack, said gate stack comprising a high-k dielectric segment situated over said substrate and a gate electrode segment situated over said high-k dielectric segment, said method being characterized by:

performing a nitridation process on said gate stack.

9. The method of claim 8 wherein said step of performing said nitridation process on said gate stack comprises utilizing a plasma to nitridate sidewalls of said gate stack, said plasma comprising nitrogen.

10. The method of claim 8 wherein said step of performing said nitridation process on said gate stack causes nitrogen to enter said high-k dielectric segment, said nitrogen forming an oxygen diffusion barrier in said high-k dielectric segment.

11. The method of claim 8 wherein said step of etching said gate electrode layer and said high-k dielectric layer to form said gate stack is performed in a process chamber, said process chamber being utilized to perform said step of performing said nitridation process on said gate stack.

12. The method of claim 8 wherein said step of etching said gate electrode layer and said high-k dielectric layer to form said gate stack is performed in a first process chamber and said step of performing said nitridation process on said gate stack is performed in a second process chamber.

13. The method of claim 8 wherein said high-k dielectric segment is selected from the group consisting of hafnium oxide, hafnium silicate, zirconium oxide, zirconium silicate, and aluminum oxide.

14. The method of claim 8 wherein said gate electrode segment comprises polysilicon.

15. A method for forming a field-effect transistor on a substrate, said substrate including a high-k dielectric layer situated over said substrate and a gate electrode layer situated over said high-k dielectric layer, said method comprising steps of:

etching said gate electrode layer and said high-k dielectric layer to form a gate stack, said gate stack comprising a high-k dielectric segment situated over said substrate and a gate electrode segment situated over said high-k dielectric segment, said gate stack comprising sidewalls;

utilizing a nitrogen plasma to nitridate said sidewalls of said gate stack.

16. The method of claim 15 wherein said step of utilizing said nitrogen plasma to nitridate said sidewalls of said gate stack causes nitrogen to enter said high-k dielectric segment, said nitrogen forming an oxygen diffusion barrier in said high-k dielectric segment.

17. The method of claim 15 wherein said step of etching said gate electrode layer and said high-k dielectric layer to form said gate stack is performed in a process chamber, said process chamber being utilized to perform said step of utilizing a nitrogen plasma to nitridate said sidewalls of said gate stack.

18. The method of claim 15 wherein said step of etching said gate electrode layer and said high-k dielectric layer to form said gate stack is performed in a first process chamber and said step of utilizing a nitrogen plasma to nitridate said sidewalls of said gate stack is performed in a second process chamber.

19. The method of claim 15 wherein said high-k dielectric segment is selected from the group consisting of hafnium oxide, hafnium silicate, zirconium oxide, zirconium silicate, and aluminum oxide.

20. The method of claim 15 wherein said gate electrode segment comprises polysilicon.