Process for reducing hydrogen contamination in dielectric materials in memory devices

• US 6,740,605 B1
• Filed: 05/05/2003
• Issued: 05/25/2004
• Est. Priority Date: 05/05/2003
• Status: Expired due to Fees

• Current Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Original Assignee: Advanced Micro Devices, Inc., Fujitsu Limited
• Inventors: Shiraiwa, Hidehiko, Park, Jaeyong, Cheung, Fred T K, Halliyal, Arvind
• Primary Examiner(s): GUERRERO, MARIA F
• Application Number:
  US10/429,447
• Time in Patent Office: 386 Days
• Field of Search: 438/778, 438/780, 438/781, 438/795, 438/798, 438/787, 438/791, 438/769, 438/770, 438/775, 438/799, 438/471, 438/473, 438/474
• US Class Current: 438/795
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/3144 on silicon
• CPC Class Codes: H01L 29/40117 the electrodes comprising a charge-trapping insulator
• CPC Class Codes: H01L 29/66833 with a charge trapping gate insulator, e.g. MNOS transistors

Abstract

The present invention, in one embodiment, relates to a process for fabricating a semiconductor device that is less susceptible to performance degradation caused by hydrogen contamination. The method includes the steps for removing unwanted hydrogen bonds by exposing the hydrogen bonds to ultraviolet radiation sufficient to break the bond and annealing in an atmosphere comprising at least one gas having at least one atom capable of forming bonds that replace the hydrogen bonds.

Claims

1. A process for removing hydrogen contamination from a semiconductor device comprising:

forming at least one dielectric layer, wherein the dielectric layer comprises dielectric-hydrogen bonds;

irradiating the dielectric layer with ultraviolet radiation sufficient to break at least a portion of the dielectric-hydrogen bonds; and

annealing the dielectric layer in an atmosphere comprising at least one gas having at least one atom capable of forming dielectric-atom bonds, whereby at least a portion of dielectric-hydrogen bonds are replaced with dielectric-atom bonds,

wherein the dielectric layer is one or more of a nitride layer, a high-K dielectric material layer and a composite dielectric material layer.

2. The process of claim 1, wherein the dielectric-hydrogen bonds comprise one or more of silicon-hydrogen bonds, nitrogen-hydrogen bonds, oxygen-hydrogen bonds, and metal-hydrogen bonds.

3. The process of claim 1, wherein the at least one atom is one or more of deuterium, fluorine, oxygen, silicon, and nitrogen.

4. The process of claim 1, wherein the dielectric layer is one or more of a charge storage layer, a spacer, and an etch stop layer.

5. The process of claim 1, wherein the dielectric layer is a nitride layer.

6. The process of claim 1, wherein the atmosphere comprises from about 5% by volume to about 95% by volume of the at least one gas having at least one atom capable of forming dielectric-atom bonds and from about 95% by weight to about 5% by weight of the at least one inert gas.

7. The process of claim 1, wherein the ultraviolet radiation is applied at an energy of from about 3 eV to about 8 eV.

8. The process of claim 1, wherein the ultraviolet radiation is applied at wavelengths from about 160 nm to about 400 nm.

9. The process of claim 1, wherein the steps of irradiating and annealing are repeated at least once.

10. The process of claim 1, wherein the steps of irradiating and annealing are performed substantially simultaneously.

11. The process of claim 1, wherein the dielectric layer is a charge storage layer of an ONO comprising a bottom dielectric layer, a charge storage layer, and a top dielectric layer.

12. The process of claim 11, wherein the charge storage layer is formed over the bottom dielectric layer, the bottom dielectric layer and the charge storage layer, forming an interface comprising dielectric-hydrogen bonds.

13. The process of claim 12, further comprising the steps of:

forming a top dielectric layer over the charge storage layer, the top dielectric layer and the charge storage layer forming a top interface comprising dielectric-hydrogen bonds;

irradiating the top interface with ultraviolet radiation sufficient to break at least a portion of the dielectric-hydrogen bonds; and

annealing the top interface in an atmosphere comprising at least one gas having at least one atom capable of forming dielectric-atom bonds, whereby at least a portion of dielectric-hydrogen bonds are replaced with dielectric-atom bonds.

14. The process of claim 13, wherein the interface and the top interface are irradiated in the same step, and wherein the interface and the top interface are annealed in the same step.

15. A process for fabricating a semiconductor device comprising:

providing a semiconductor substrate;

forming an ONO material over the semiconductor substrate;

forming a gate electrode layer over the ONO material;

forming a dielectric spacer adjacent to the ONO and a dielectric etch stop layer over the gate electrode layer and protective spacer such that at least one of the dielectric spacer and dielectric etch stop layer comprises dielectric-hydrogen bonds;

irradiating at least one of the dielectric spacer and the dielectric etch stop layer with ultraviolet radiation sufficient to break at least a portion of the dielectric-hydrogen bonds; and

annealing at least one of the spacer and the etch stop layer in an atmosphere comprising at least one gas having at least one atom capable of forming dielectric-atom bonds, whereby at least a portion of dielectric-hydrogen bonds are replaced with dielectric-atom bonds,

wherein at least one of the dielectric spacer and the dielectric etch stop layer is one or more of a nitride layer, a high-K dielectric material layer and a composite dielectric material layer.

16. The process of claim 15 wherein the step of annealing is carried out at a temperature ranging from about 600°

C. to about 900°

C.

17. A process for fabricating a semiconductor device comprising:

providing a semiconductor substrate;

forming an oxide layer over the semiconductor substrate;

forming a nitride layer over the oxide layer, the oxide layer and the nitride layer forming an interface comprising silicon-hydrogen and nitrogen-hydrogen bonds;

irradiating the interface with ultraviolet radiation sufficient to break at least a portion of at least one of the silicon-hydrogen and nitrogen-hydrogen bonds; and

annealing the interface in an atmosphere comprising at least one gas having at least one atom capable of forming at least one of silicon-atom bonds and nitrogen-atom bonds, whereby at least a portion of at least one of the silicon-hydrogen bonds and nitrogen-hydrogen bonds are replaced with at least one of the silicon-atom bonds and nitrogen-atom bonds.

18. The process of claim 17, wherein the ultraviolet radiation is applied at an energy of from about 3.9 eV to about 8.1 eV.

19. The process of claim 18, wherein the atmosphere comprises from about 5% by volume to about 95% by volume of the at least one gas having at least one atom capable of forming dielectric-atom bonds and from about 95% by weight to about 5% by weight of the at least one inert gas, wherein the anneal conditions comprise a temperature in the range from about 300°

C. to about 1200°

C.

20. The process of claim 19, wherein the steps of irradiating and annealing are performed substantially simultaneously.