ATOMIC LAYER DEPOSITION OF HAFNIUM LANTHANUM OXIDES

• US 20100270626A1
• Filed: 04/27/2009
• Published: 10/28/2010
• Est. Priority Date: 04/27/2009
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Raisanen, Petri I.
• Granted Patent: US 8,071,452 B2
• Time in Patent Office: Days
• US Class Current: 257/410
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• 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 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence
• CPC Class Codes: H01L 29/40114 the electrodes comprising a conductor-insulator-conductor-insulator-semiconductor structure
• CPC Class Codes: H01L 29/513 the variation being perpendicular to the channel plane
• 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 29/7881 Programmable transistors with only two possible levels of programmation H01L29/7888 takes precedence

Abstract

There is provided an improved method for depositing thin films using precursors to deposit binary oxides by atomic layer deposition (ALD) techniques. Also disclosed is an ALD method for depositing a high-k dielectric such as hafnium lanthanum oxide (HfLaO) on a substrate. Embodiments of the present invention utilize a combination of ALD precursor elements and cycles to deposit a film with desired physical and electrical characteristics. Electronic components and systems that integrate devices fabricated with methods consistent with the present invention are also disclosed.

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 first precursor gas pulse sequence, wherein the first precursor gas sequence includes;

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

exposing the substrate to a first oxidant gas for a first oxidation pulse interval then removing the first oxidation gas thereafter;

exposing the substrate to a second precursor gas pulse sequence, wherein the second sequence includes;

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

exposing the substrate to a second oxidant gas for a second oxidation pulse interval then removing the second oxidation gas thereafter;

wherein the first precursor gas comprises at least one of tetrakis-ethyl-methylamino hafnium (TEMAHf) and lanthanum tris-formamidinate (LaFAMD)₃.

2. The method of claim 1 wherein the second precursor gas comprises at least one of tetrakis-ethyl-methylamino hafnium (TEMAHf) and lanthanum tris-formamidinate (LaFAMD)₃.

3. The method of claim 1 wherein the first precursor gas comprises TEMAHf and the second precursor gas comprises (LaFAMD)₃.

4. The method of claim 1 wherein the first oxidant gas and the second oxidant gas comprise one or more of the group selected from O, O₂, O₃, H₂O, H₂O₂, NO, N₂O, N₂O₅ and NO₂.

5. The method of claim 2 wherein each of the first oxidant gas and the second oxidant gas comprises O₂ and O₃.

6. The method of claim 5 wherein each of the first oxidant gas and the second oxidant gas comprises approximately 10 atomic percent to 20 atomic percent O₃.

7. The method of claim 5 wherein each of the first oxidant gas and the second oxidant gas comprises approximately 12 atomic percent to 18 atomic percent O₃.

8. The method of claim 1 further comprising repeating the atomic layer deposition cycle until the deposited film has reached a predetermined thickness.

9. The method of claim 1 further comprising in any atomic layer deposition cycle:

performing the first precursor gas pulse sequence a predetermined number of n iterations; and

performing the second precursor gas pulse sequence a predetermined number of m iterations, wherein the ratio of n;

m is 1;

1.

10. The method of claim 9 wherein the ratio if n:

m is greater than 1.

11. The method of claim 9 wherein the ratio if n:

m is less than 1.

12. The method of claim 9 wherein the n iterations of the first precursor gas sequence are performed before the m iterations of the second precursor gas sequence.

13. The method of claim 9 wherein the number of n iterations and the number of m iterations are determined by at least one of:

a dielectric constant of the deposited film;

an index of refraction of the deposited film;

a molecular composition of the deposited film; and

a ratio of atomic hafnium to atomic lanthanum to be deposited in the deposited film.

14. The method of claim 1 wherein:

the first precursor pulse interval is in the range of 300 milliseconds to 5 seconds;

the first oxidation pulse interval is in the range of 50 milliseconds to 10 seconds;

the second precursor pulse interval is in the range of 500 ms to 10 seconds; and

the first oxidation pulse interval is in the range of 50 milliseconds to 10 seconds.

15. The method of claim 1 wherein:

the first precursor pulse interval is in the range of 1 second to 2 seconds;

the first oxidation pulse interval is in the range of 50 milliseconds to 2 seconds;

the second precursor pulse interval is in the range of 1 second to 4 seconds; and

the first oxidation pulse interval is in the range of 50 milliseconds to 2 seconds.

16. The method of claim 1 wherein the first precursor gas sequence deposits a first sequence film on the substrate wherein the first sequence film is deposited with a thickness between 0.8-1.1 Å

per first precursor gas sequence.

17. The method of claim 1 wherein the second precursor gas sequence deposits a second sequence film on the substrate wherein the second sequence film is deposited with a thickness between 0.6-0.8 Å

per second precursor gas sequence.

18. The method of claim 1 wherein the film deposited by the atomic layer deposition cycle deposits the film with a thickness between 1.4-2.7 Å

per deposition cycle.

19. The method of claim 1 wherein during the atomic layer deposition cycle, the substrate is maintained at a temperature in the range of 140°

C. to 300°

C.

20. The method of claim 1 wherein during the atomic layer deposition cycle, the substrate is maintained at a temperature in the range of 175°

C. to 250°

C.

21. The method of claim 1 wherein during the atomic layer deposition cycle, a vessel temperature of at least one of the first precursor gas and the second precursor gas is maintained at a temperature in the range of 135°

C. to 145°

C.

22. The method of claim 1 wherein removing the first precursor gas, removing the first oxidation gas, removing the second precursor gas and removing the second oxidation gas comprises at least one of:

evacuating gas from the reaction chamber for a predetermined evacuation period; and

introducing a purge gas into the reaction chamber for a purge period, wherein;

the purge gas comprises one or more of the group consisting of;

argon, nitrogen, helium, hydrogen, forming gas, krypton, and xenon; and

the purge period is in the range of approximately 500 milliseconds to 10 seconds.

23. The method of claim 22 wherein the purge period is in the range of approximately 500 milliseconds to 4 seconds.

24. The method of claim 22 wherein the purge period is in the range of approximately 3 seconds to 10 seconds.

32. An electronic device comprising a HfLaO dielectric layer and a conductive layer in communication with the dielectric layer, the dielectric layer deposited in a film by

applying an atomic layer deposition cycle according to claim 1 to the substrate.

33. The electronic device of claim 32 wherein the first oxidant gas and the second oxidant gas comprise a mixture of O₂ and O₃, and wherein the mixture comprises approximately 12 atomic percent to 18 atomic percent O₃.

34. The electronic device of claim 32 further comprising repeating the atomic layer deposition cycle until the dielectric layer has reached a predetermined thickness.

35. The electronic device of claim 32 further comprising repeating the first precursor gas pulse sequence a plurality of times before exposing the substrate to the second precursor gas sequence.

36. The electronic device of claim 32 wherein:

the first precursor pulse interval is in the range of 1 second to 2 seconds;

the first oxidation pulse interval is in the range of 50 milliseconds to 2 seconds;

the second precursor pulse interval is in the range of 1 second to 4 seconds; and

the first oxidation pulse interval is in the range of 50 milliseconds to 2 seconds.

37. The electronic device of claim 32 wherein during the atomic layer deposition cycle, the substrate is maintained at a temperature in the range of 175°

C. to 250°

C.

38. The electronic device of claim 32 a vessel temperature of a vessel holding at least one of the first precursor gas and the second precursor gas is maintained at a temperature in the range of 135°

C. to 145°

C.

39. The electronic device of claim 32 wherein the electronic device comprises at least one of a capacitor, a transistor, a FLASH memory cell, and a DRAM memory cell.

40. An electronic system comprising:

a processor;

a memory device coupled to the processor, wherein the memory device includes a plurality of transistors, wherein the transistors include an HfLaO dielectric layer and a conductive layer in communication with the dielectric layer, the dielectric layer deposited in a film by applying an atomic layer deposition cycle according to claim 1 to the substrate.

41. The electronic device of claim 40 wherein the first oxidant gas and the second oxidant gas comprise a mixture of O₂ and O₃, and wherein the mixture comprises approximately 12 atomic percent to 18 atomic percent O₃.

42. The electronic device of claim 40 further comprising repeating the atomic layer deposition cycle until the dielectric layer has reached a predetermined thickness.

43. The electronic device of claim 40 further comprising repeating the first precursor gas pulse sequence a predetermined plurality of times before exposing the substrate to the second precursor gas sequence.

44. The electronic device of claim 40 wherein:

the first precursor pulse interval is in the range of 1 second to 2 seconds;

the first oxidation pulse interval is in the range of 50 milliseconds to 2 seconds;

the second precursor pulse interval is in the range of 1 second to 4 seconds; and

the first oxidation pulse interval is in the range of 50 milliseconds to 2 seconds.

45. The electronic device of claim 40 wherein during the atomic layer deposition cycle, the substrate is maintained at a temperature in the range of 175°

C. to 250°

C.

46. The electronic device of claim 40 a vessel temperature of a vessel holding at least one of the first precursor gas and the second precursor gas is maintained at a temperature in the range of 135°

C. to 145°

C.

47. The electronic device of claim 40 wherein the electronic system comprises at least one of a computer, a mobile subscriber unit such as a cellular telephone or smart phone, and a PDA.

25. 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 first precursor gas pulse sequence, wherein the first sequence includes;

exposing the substrate to a first precursor gas comprising tetrakis-ethyl-methylamino hafnium (TEMAHf) for a first precursor pulse interval;

removing the first precursor gas by introducing a purge gas into the reaction chamber for a first precursor purge period;

exposing the substrate to a first oxidant gas for a first oxidation pulse interval; and

removing the first oxidant gas by introducing the purge gas into the reaction chamber for a first oxidant purge period;

exposing the substrate to a second precursor gas pulse sequence, wherein the first sequence includes;

exposing the substrate to a second precursor gas comprising Lanthanum tris-formamidinate (LaFAMD)₃ for a second precursor pulse interval;

removing the first precursor gas by introducing the purge gas into the reaction chamber for a second precursor purge period;

exposing the substrate to a second oxidant gas for a second oxidation pulse interval; and

removing the second oxidant gas by introducing the purge gas into the reaction chamber for a second oxidant purge period.

26. The method of claim 25 wherein each of the first oxidant gas and the second oxidant gas comprises a mixture of O₂ and O₃, and wherein the mixture comprises approximately 10 atomic percent to 18 atomic percent O₃.

27. The method of claim 25 further comprising repeating the atomic layer deposition cycle until the deposited film has reached a predetermined thickness.

28. The method of claim 25 further comprising repeating the first precursor gas pulse sequence a plurality of times before exposing the substrate to the second precursor gas sequence.

29. The method of claim 25 wherein:

the first precursor pulse interval is in the range of about 1 second to 2 seconds;

the first oxidation pulse interval is in the range of 50 milliseconds to 2 seconds;

the second precursor pulse interval is in the range of 1 second to 4 seconds; and

the first oxidation pulse interval is in the range of 50 milliseconds to 2 seconds.

30. The method of claim 25 wherein during the atomic layer deposition cycle, the substrate is maintained at a temperature in the range of 175°

C. to 250°

C.

31. The method of claim 25 wherein during the atomic layer deposition cycle, a vessel temperature of a vessel holding at least one of the first precursor gas and the second precursor gas is maintained at a temperature in the range of 135°

C. to 145°

C.