Atomic layer deposition method for depositing a layer

• US 7,579,285 B2
• Filed: 07/10/2006
• Issued: 08/25/2009
• Est. Priority Date: 07/11/2005
• Status: Active Grant

• Current Assignee: IMEC International
• Original Assignee: IMEC International
• Inventors: Zimmerman, Paul, Ragnarsson, Lars-Ake, De Gendt, Stefan, Caymax, Matty, Delabie, Annelies
• Primary Examiner(s): EVERHART, CARIDAD
• Application Number:
  US11/484,229
• Publication Number:
  US 20070049045A1
• Time in Patent Office: 1,142 Days
• Field of Search: 438/785, 438/788, 438/681, 438/799, 438/798, 427/255.31, 257/E21.478, 257/E21.487, 257/E21.471, 257/E21.475, 257/E21.576
• US Class Current: 438/785
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45536 Use of plasma, radiation or electromagnetic fields
• CPC Class Codes: C23C 16/482 using incoherent light, UV to IR, e.g. lamps
• CPC Class Codes: C23C 16/483 using coherent light, UV to IR, e.g. lasers
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/0231 treatment by exposure to electromagnetic radiation, e.g. UV light
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]

Abstract

The invention is related to an ALD method for depositing a layer including the steps of a) providing a semiconductor substrate in a reactor; b) providing a pulse of a first precursor gas into the reactor; c) providing a pulse of a second precursor gas into the reactor; d) providing an inert atmosphere in the reactor; and e) repeating step b) through step d), wherein at least once during step d) the semiconductor substrate is exposed to UV irradiation.

Claims

1. An atomic layer deposition method for depositing a layer comprising the steps of:

a) providing a semiconductor substrate in a reactor;

b) providing a pulse of a first precursor gas into the reactor;

c) providing a pulse of a second precursor gas into the reactor; and

d) providing an inert atmosphere in the reactor; and

after completion of step a), step b), step c, and step d),

e) repeating at least once steps of providing a pulse of a first precursor gas into the reactor;

providing a pulse of a second precursor gas into the reactor; and

providing an inert atmosphere in the reactor;

wherein the semiconductor substrate is exposed to UV irradiation at least once during step d), and whereby a layer is obtained by atomic layer deposition.

2. The method according to claim 1, wherein the first precursor gas is selected from the group consisting of metal halides, metal oxyhalides, and metalorganics.

3. The method according to claim 1, wherein a trace amount of at least one of water, hydrogen peroxide, hydrogen, or any other species capable of forming hydroxyls in combination with the first precursor gas and the second precursor gas is present in the inert atmosphere.

4. The method according to claim 1, wherein the exposure to UV irradiation is stopped after 10 deposition cycles.

5. The method according to claim 1, wherein the exposure to UV irradiation is stopped after 5 deposition cycles.

6. The method according to claim 1, wherein the exposure to UV irradiation is stopped after 2 deposition cycles.

7. The method according to claim 1, wherein the exposure to UV irradiation is stopped after 1 deposition cycle.

8. The method according to claim 1, wherein the semiconductor substrate is exposed 10 times to UV irradiation.

9. The method according to claim 1, wherein the semiconductor substrate is exposed 5 times to UV irradiation.

10. The method according to claim 1, wherein the semiconductor substrate is exposed 2 times to UV irradiation.

11. The method according to claim 1, wherein the semiconductor substrate is exposed once to UV irradiation.

12. The method according to claim 1, wherein the semiconductor substrate comprises a material selected from the group consisting of silicon, silicon-on-insulator, germanium, germanium-on-insulator, and any combination thereof.

13. The method according to claim 1, wherein the first precursor gas is HfC14, and wherein the second precursor gas is H2O.

14. The method according to claim 1, wherein the inert gas is nitrogen.

15. A semiconductor device produced by a method according to claim 1.

16. The method according to claim 1, wherein organic species are excluded from the reactor to avoid significant contamination to the layer.

17. The method according to claim 1, wherein a thickness of the layer formed is increased when compared to a method conducted without exposure of the semiconductor substrate to UV irradiation in an inert atmosphere in the reactor.

18. The method according to claim 1, comprising at least one additional step of providing an inert atmosphere in the reactor, wherein the at least one additional step is conducted between step (a) and step (b);

between step (b) and step (c);

or between each of step (a), step (b), and step (c).

19. The method according to claim 18, wherein the UV irradiation exposure is performed during any one of the steps of providing an inert atmosphere in the reactor.

20. The method according to claim 18, wherein the UV irradiation exposure is performed during each step of providing an inert atmosphere in the reactor.

21. The method according to claim 1, wherein the second precursor gas comprises a gas capable of forming at least one oxide or oxynitride in combination with the first precursor gas.

22. The method according to claim 21, wherein the gas capable of forming at least one oxide or oxynitride is selected from the group consisting of H₂O, H₂O₂, O₂, and O₃.

23. The method according to claim 1, wherein a wavelength of the UV irradiation is selected to provide sufficient energy to increase dissociation of the first precursor and increase formation of hydroxyls, when compared to a method conducted without exposure of the semiconductor substrate to UV irradiation.

24. The method according to claim 23, wherein the wavelength of the UV irradiation is lower than 205 nm.

25. The method according to claim 23, wherein the wavelength of the UV irradiation is lower than 195 nm.

26. The method according to claim 23, wherein the wavelength of the UV irradiation is lower than 185 nm.

27. The method according to claim 23, wherein the wavelength of the UV irradiation is lower than 175 nm.

28. The method according to claim 1, wherein the inert atmosphere is provided by purging an inert gas such as a noble gas or nitrogen.

29. The method according to claim 28, wherein the inert gas is a noble gas or nitrogen.

30. The method according to claim 1, wherein said semiconductor substrate is exposed to heat during exposure to UV irradiation.

31. The method according to claim 30, wherein the semiconductor substrate is exposed to a temperature of from about room temperature to about 350°

C.

32. The method according to claim 30, wherein step b) through d) are performed at a temperature of from about 100°

C. to about 250°

C.

33. The method according to claim 30, wherein step b) through d) are performed at a temperature of from about 150°

C. to about 220°

C.

34. The method according to claim 1, further comprising repeating at least once steps of providing a pulse of a first precursor gas into the reactor;

providing a pulse of a second precursor gas into the reactor; and

providing an inert atmosphere in the reactor, wherein the steps are conducted before step b).

35. The method according to claim 34, wherein the UV irradiation exposure is performed during at least one of the steps of providing an inert atmosphere in the reactor conducted before step b).

36. An atomic layer deposition method for depositing a layer comprising the steps of:

a) providing a semiconductor substrate in a reactor;

b) providing a pulse of a first precursor gas into the reactor;

c) providing a pulse of a second precursor gas into the reactor; and

d) providing an inert atmosphere in the reactor after step (c) and providing an inert atmosphere in the reactor between step (a) and step (b);

between step (b) and step (c);

or between each of step (a), step (b), and step (c); and

after completion of step a), step b), step c, and step d),

e) repeating at least once steps of providing a pulse of a first precursor gas into the reactor;

providing a pulse of a second precursor gas into the reactor; and

providing an inert atmosphere in the reactor;

wherein the semiconductor substrate is exposed to UV irradiation at least once during step d), and whereby a layer is obtained by atomic layer deposition, and wherein the UV irradiation exposure is performed during two or more of the steps of providing an inert atmosphere in the reactor.

37. An atomic layer deposition method for depositing a layer comprising the steps of:

a) providing a semiconductor substrate in a reactor;

b) providing a pulse of a first precursor gas into the reactor;

c) providing a pulse of a second precursor gas into the reactor; and

d) providing an inert atmosphere in the reactor; and

after completion of step a), step b), step c, and step d),

e) repeating at least once steps of providing a pulse of a first precursor gas into the reactor;

providing a pulse of a second precursor gas into the reactor; and

providing an inert atmosphere in the reactor;

wherein the semiconductor substrate is exposed to UV irradiation at least once during step d), and whereby a layer is obtained by atomic layer deposition, and wherein the layer has an increased density at an interface between the layer and the semiconductor substrate, such that defects at the interface are reduced, thereby improving an electrical characteristic of the layer.