Ozone-enhanced oxidation for high-k dielectric semiconductor devices

• US 20030032303A1
• Filed: 08/13/2001
• Published: 02/13/2003
• Est. Priority Date: 08/13/2001
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Lin, Yeou-Ming, Yu, Mo-Chiun
• Granted Patent: US 6,573,193 B2
• Time in Patent Office: Days
• US Class Current: 438/770
• CPC Class Codes: H01L 21/02323 introduction of oxygen
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/02356 treatment to change the morphology of the insulating layer, e.g. transformation of an amorphous layer into a crystalline layer
• CPC Class Codes: H01L 21/28185 with a treatment, e.g. annealing, after the formation of the gate insulator and before the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28211 in a gaseous ambient using an oxygen or a water vapour, e.g. RTO, possibly through a layer H01L21/28194 and H01L21/28202 take precedence
• CPC Class Codes: H01L 21/28247 passivation or protection of the electrode, e.g. using re-oxidation
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/31691 with perovskite structure

Abstract

A low temperature ozone-enhanced oxidation process is presented whereby amorphous high dielectric constant film devices are subject to oxidation processes at temperatures whereby crystallization of the amorphous high dielectric constant film is avoided, thereby lowering leakage currents and reducing the required thickness to achieve an equivalent SiO₂ thickness (EOT).

Claims

1. A method for carrying out a low temperature oxidation process on a high dielectric constant film comprising the steps of:

providing a semiconductor device comprising an amorphous film having a dielectric constant of at least about 20 deposited on a substrate;

heating the amorphous film in the presence of an ozone containing ambient to a temperature below a crystallization temperature of the amorphous film; and

forming an oxide film over the semiconductor device.

2. The method of claim 1, wherein the step of heating the amorphous film is carried out within a range of temperature from about 450 degrees Centigrade to about 550 degrees Centigrade.

3. The method of claim 1, wherein the dielectric constant of the amorphous film has a value from about 20 to about 40.

4. The method of claim 1, wherein the ozone containing ambient comprises a mixture of at least ozone and oxygen.

5. The method of claim 1, wherein a concentration of ozone in the ozone containing ambient is varied whereby a growth rate of the oxide film over the semiconductor device varies in direct proportion thereto.

6. The method of claim 4, wherein a concentration of ozone in the ozone containing ambient is varied whereby a growth rate of the oxide film over the semiconductor device varies in direct proportion thereto.

7. The method of claim 1, wherein the temperature of the ambient is varied whereby a growth rate of the oxide film over the semiconductor device varies in direct proportion thereto.

8. The method of claim 4, wherein the temperature of the amorphous film is varied whereby a growth rate of the oxide film over the semiconductor device varies in direct proportion thereto.

9. The method of claim 1, wherein at least one of the temperature of the amorphous film and a concentration of the ozone containing ambient is varied whereby a growth rate of the oxide film over the semiconductor device varies in response thereto.

10. The method of claim 9, wherein a thickness of the oxide film varies over a range of about 15 Angstroms to about 50 Angstroms.

11. The method of claim 1, wherein the steps of said process are carried out at a temperature for a period of time such that crystallization of the amorphous film is avoided.

12. The method of claim 1, wherein the semiconductor device comprises a front-end gate oxide.

13. The method of claim 1, wherein said steps follow a wet chemical etching process.

14. The method of claim 13, wherein the wet chemical etching process comprises the use of HF and H₃PO₄.

15. The method of claim 1, wherein said steps replace a process comprising a rapid thermal oxidation step.

16. The method of claim 15, wherein said steps are carried out at a temperature for a period of time such that crystallization of the amorphous film is avoided.

17. The method of claim 16, wherein said steps are carried out at a temperature for a period of time such that formation of an interfacial oxide layer is avoided.

18. The method of claim 13, wherein said steps are carried out at a temperature and a period of time such that an etching damage is removed and crystallization of the amorphous film is avoided.

19. The method of claim 1, wherein said steps replace a process comprising a poly-gate oxidation carried out within a temperature range of about 800 to about 1100 degrees Centigrade.

20. A method for carrying out a low temperature enhanced ozone oxidation process on a front-end gate dielectric device comprising the steps of:

providing a front end gate dielectric device comprising an amorphous film; and

heating the amorphous film in the presence of an ozone containing ambient to a temperature for a period of time such that crystallization of the amorphous film is avoided.