SYSTEMS AND METHODS FOR THIN-FILM DEPOSITION OF METAL OXIDES USING EXCITED NITROGEN-OXYGEN SPECIES

• US 20110275166A1
• Filed: 05/06/2011
• Published: 11/10/2011
• Est. Priority Date: 05/07/2010
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Wang, Chang-Gong, Jung, Sung-Hoon, Raisanen, Petri I., Shero, Eric J.
• Granted Patent: US 8,877,655 B2
• Time in Patent Office: Days
• US Class Current: 438/5
• CPC Class Codes: C23C 16/30 Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• CPC Class Codes: C23C 16/308 Oxynitrides
• CPC Class Codes: C23C 16/40 Oxides
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02183 the material containing tantalum, e.g. Ta2O5
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/02192 the material containing at least one rare earth metal element, e.g. oxides of lanthanides, scandium or yttrium
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• 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 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence

Abstract

The present invention relates to a process and system for depositing a thin film onto a substrate. One aspect of the invention is depositing a thin film metal oxide layer using atomic layer deposition (ALD).

Claims

1. A method for depositing a film on a substrate that is within a reaction chamber, the method comprising applying an atomic layer deposition cycle to the substrate, the cycle comprising:

exposing the substrate to a precursor gas for a precursor pulse interval and then removing the precursor gas; and

exposing the substrate to an oxidizer comprising an oxidant gas and a nitrogen-containing species gas for an oxidation pulse interval and then removing the oxidizer.

2. The method of claim 1 wherein the precursor gas comprises a rare earth metal selected from the group consisting of Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu, and combinations thereof.

3. The method of claim 1 wherein the precursor gas comprises at least one of an organo-metallic and a metal halide compound.

4. The method of claim 1 wherein the precursor gas comprises at least one of:

hafnium tetrachloride (HfCl₄);

titanium tetrachloride (TiCl₄);

tantalum pentachloride (TaCl₅);

tantalum pentafluoride (TaF₅);

zirkonium tetrachloride (ZrCl₄);

rare earth betadiketonate compounds including (La(THD)₃) and (Y(THD)₃);

rare earth cyclopentadienyl (Cp) compounds including La(iPrCp)₃;

rare earth amidinate compounds including lanthanum tris-formamidinate La(FAMD)₃;

cyclooctadienyl compounds including rare earth metals;

alkylamido compounds including;

tetrakis-ethyl-methylamino hafnium (TEMAHf);

tetrakis (diethylamino) hafnium ((Et₂N)₄Hf or TDEAH); and

tetrakis (dimethylamino) hafnium ((Me₂N)₄Hf or TDMAH);

alkoxides;

halide compounds of silicon;

silicon tetrachloride;

silicon tetrafluoride; and

silicon tetraiodide.

5. The method of claim 1 wherein the oxidant gas is the nitrogen-containing species gas.

6. The method of claim 1 wherein the nitrogen-containing species gas includes activated ionic or radical species including at least one of NO*, N₂O*, NO₂*, NO₃*, and N₂O₅*.

7. The method of claim 1 wherein the oxidant gas comprises ozone and one or more gasses selected from the group consisting of O, O₂, NO, N₂O, NO₂, NO₃, N₂O₅, an NxOy radical species, an NxOy ionic species, and combinations thereof.

8. The method of claim 7 wherein the oxidant gas comprises approximately 5 atomic percent to 25 atomic percent O₃.

9. The method of claim 7 wherein O₃ is produced from O₂ and a nitrogen source gas wherein a mixture of the O₂ and nitrogen source gas is subjected to a plasma discharge.

10. The method of claim 9 wherein the nitrogen source gas is at least one of N₂, NO, N₂O, NO₂, NO₃, and N₂O₅.

11. The method of claim 1 wherein the nitrogen-containing species gas comprises one or more of the group consisting of:

an excited N_xO_y radical species, an excited N_xO_y ionic species, and combinations thereof.

12. The method of claim 1 wherein the oxidant gas comprises a mixture of two or more of O, O₂, NO, N₂O, NO₂, NO₃, N₂O₅, NO_x, N_xO_y, radicals thereof, and O₃, and wherein the mixture comprises approximately 5 atomic percent to 25 atomic percent O₃.

13. The method of claim 10 wherein a flow ratio of N₂/O₂ is >

0.001.

14. The method of claim 10 wherein the ratio of the O₂ and the nitrogen source gas determine at least one of:

an amount of a nitrogen-containing species gas comprising activated ionic or radical species including at least one of NO*, N₂O*, NO₂*, NO₃*, and N₂O₅*;

a concentration of a nitrogen-containing species gas comprising activated ionic or radical species including at least one of NO*, N₂O*, NO₂*, NO₃*, and N₂O₅*;

a growth rate of the deposited film;

a film uniformity across the substrate;

a dielectric constant of the deposited film;

an index of refraction of the deposited film; and

a molecular composition of the deposited film.

15. The method of claim 10 wherein a power input controls the plasma, and an amount of power delivered to the plasma determine at least one of:

an amount of a nitrogen-containing species gas comprising activated ionic or radical species including at least one of NO*, N2O*, NO2*, NO₃*, and N2O5*;

a concentration of a nitrogen-containing species gas comprising activated ionic or radical species including at least one of NO*, N2O*, NO2*, NO₃*, and N2O5*;

a growth rate of the deposited film;

a film uniformity across the substrate;

a dielectric constant of the deposited film;

an index of refraction of the deposited film; and

a molecular composition of the deposited film.

16. The method of claim 10 further comprising:

generating the oxidizer by exposing O₂ and a nitrogen source gas to a plasma discharge;

monitoring a ratio of O₃ and excited N_xO_y species generated by the plasma discharge; and

adjusting at least one of a power input to the plasma discharge, a temperature of a housing;

a flow rate of the O₂, and a flow rate of the nitrogen source gas to achieve a predetermined criterion.

17. The method of claim 16 wherein the predetermined criterion includes at least one of:

an oxidizer flow rate;

an oxidant/N_xO_y concentration ratio;

an active N_xO_y species concentration;

a ratio of active N_xO_y species, wherein the excited N_xO_y species gas contains a plurality of excited nitrogen-oxygen compounds; and

a concentration of a particular active nitrogen-oxygen compound.

18. The method of claim 1 further comprising:

exposing the substrate to a second precursor gas for a second precursor pulse interval then removing the second precursor gas thereafter; and

after removing the second precursor gas, exposing the substrate to an oxidizer comprising an oxidant gas and a nitrogen-containing species gas for a oxidation pulse interval then removing the oxidizer thereafter.

22. The method of claim 1 wherein the substrate comprises one or more of the group consisting of:

silicon oxide, SOI, carbon doped silicon dioxides, silicon oxides, silicon nitride, doped silicon, germanium arsenide, glass, sapphire, metal, metal nitride, or a metal alloy.

23. The method of claim 22 that further includes a barrier layer on a surface of the substrate.

24. The method of claim 23 wherein the barrier layer is comprised of one or more of the groups consisting of titanium, titanium nitride, tungsten nitride, tantalum, and tantalum nitride.

25. The method of claim 1 wherein the substrate is a circular wafer having a diameter of between 200 nm and 300 nm.

26. The method of claim 1 that is performed at a pressure of 1 m Torr to 200 Torr.

27. The method of claim 1 that is performed at a pressure of 2 Torr to 6 Torr.

28. The method of claim 1 that is performed at 3 Torr to 4 Torr.

29. The method of claim 1 that is performed at 3.5 Torr.

30. The method of claim 1 that is performed at 130°

C. to 300°

C.

31. The method of claim 1 wherein the precursor gas is included in a carrier gas.

32. The method of claim 1 wherein the oxidizer is included in a carrier gas.

33. The method of claim 1 wherein the substrate is exposed to the precursor gas for a period of 300 milliseconds to 5 seconds.

34. The method of claim 1 wherein the substrate is exposed to the precursor gas for a period of 1 second to 3 seconds.

35. The method of claim 1 that further includes the step of purging the precursor gas from the reaction chamber prior to exposing the substrate to the oxidizer.

36. The method of claim 35 wherein the purging takes 3 seconds to 10 seconds.

37. The method of claim 35 wherein the purging takes 500 milliseconds to 5 seconds.

38. The method of claim 1 wherein the nitrogen-containing species gas comprises an NxOy species created by plasma discharge.

39. The method of claim 1 wherein the oxidizing gas comprised an O₃/O₂ mixture, wherein the O₃ is in the range of 5 atomic percent to 25 atomic percent of the mixture.

40. The method of claim 1 wherein the nitrogen-containing species is an NxOy species that represents greater than 1% by volume of the oxidizer.

41. The method of claim 1 wherein the substrate is exposed to the oxidizer for 50 milliseconds to 10 seconds.

42. The method of claim 1 wherein the substrate is exposed to the oxidizer for 50 milliseconds to 2 seconds.

43. The method of claim 1 wherein, after the precursor gas has been removed, the substrate is exposed to another, or the same, precursor gas, and the substrate is exposed to the oxidizer each time the precursor gas has been removed.

44. The method of claim 43 wherein a different oxidizer is used after the removal of each precursor gas.

19. A method comprising depositing a metal oxide at least one of in any film stack using a metal halide precursor and an oxidant comprising ozone and excited nitrogen-oxygen species.

20. The method of claim 19 wherein the metal oxide comprises at least one of Al₂O₃, HfO₂, ZrO₂, La₂O₃ and Ta₂O₅.

21. The method of claim 19 wherein the metal halide comprises any metal in compound combination with any halide element.

45. A system comprising:

a reaction chamber;

a precursor reactant source coupled to the reactor chamber;

a purge gas source coupled to the reactor chamber;

an oxidizer gas source coupled to the reactor chamber;

a nitrogen-containing species source coupled to the reactor chamber; and

a system operation and control mechanism configured to cause the system to apply an atomic layer deposition cycle to a substrate, the cycle comprising;

exposing the substrate to a precursor gas for a precursor pulse interval then removing the precursor gas thereafter; and

exposing the substrate to an oxidizer comprising an oxidant gas and a nitrogen-containing species gas for an oxidation pulse interval then removing the oxidizer thereafter.

46. The system of claim 45 that further includes either a plasma discharge or an ozone generator.

47. The system of claim 45 that further includes a generator being supplied (a) O₂ from an oxidizer source, and (b) a nitrogen-bearing molecule from a nitrogen source.

48. The system of claim 45 that further includes a coronal discharge to create the nitrogen-containing species.

49. The system of claim 45 that further includes a sensor to monitor the amount of nitrogen-containing species.

50. The system of claim 49 wherein the sensor communicates with a control system to control the amount of nitrogen-containing species.

51. The system of claim 45 that further includes a mechanism for loading a substrate into the reaction chamber.

52. The system of claim 45 wherein the oxidizer gas source is coupled to the reactor chamber separate from where the nitrogen-containing source is coupled to the reaction chamber.