Atomic layer deposition with nitridation and oxidation

• US 20070059945A1
• Filed: 09/12/2005
• Published: 03/15/2007
• Est. Priority Date: 09/12/2005
• Status: Abandoned Application

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Inventors: Mohklesi, Nima
• Application Number:
  US11/224,630
• Publication Number:
  US 20070059945A1
• Time in Patent Office: Days
• US Class Current: 438/778
• CPC Class Codes: C23C 16/308 Oxynitrides
• CPC Class Codes: C23C 16/45529 specially adapted for making a layer stack of alternating different compositions or gradient compositions
• CPC Class Codes: G11C 11/5621 using charge storage in a floating gate
• CPC Class Codes: G11C 16/0483 comprising cells having several storage transistors connected in series
• CPC Class Codes: H01L 21/02148 the material containing hafnium, e.g. HfSiOx or HfSiON
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• 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 21/02222 the compound being a silazane
• 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 21/3142 of nano-laminates, e.g. alternating layers of Al203-Hf02
• CPC Class Codes: H01L 21/3143 composed of alternated layers or of mixtures of nitrides and oxides or of oxinitrides, e.g. formation of oxinitride by oxidation of nitride layers
• CPC Class Codes: H01L 21/31645 Deposition of Hafnium oxides, e.g. HfO2
• CPC Class Codes: H01L 21/318 composed of nitrides
• CPC Class Codes: H01L 29/40114 the electrodes comprising a conductor-insulator-conductor-insulator-semiconductor structure
• CPC Class Codes: H01L 29/42324 Gate electrodes for transistors with a floating gate
• 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 29/7883 charging by tunnelling of carriers, e.g. Fowler-Nordheim tunnelling
• CPC Class Codes: H10B 41/30 : characterised by the memory core region
• CPC Class Codes: H10B 41/35 : with a cell select transistor, e.g. NAND
• CPC Class Codes: H10B 41/40 : characterised by the peripheral circuit region
• CPC Class Codes: H10B 41/48 : with a tunnel dielectric layer also being used as part of the peripheral transistor
• CPC Class Codes: H10B 69/00 : Erasable-and-programmable ROM [EPROM] devices not provided for in groups H10B41/00 - H10B63/00, e.g. ultraviolet erasable-and-programmable ROM [UVEPROM] devices
• CPC Class Codes: H10K 10/82 : Electrodes

Abstract

A dielectric layer is created for use with non-volatile memory and/or other devices. The dielectric layer is created using atomic layer deposition to deposit multiple components whose mole fractions change as a function of depth in the dielectric layer in order to create a rounded bottom of a conduction band profile for the dielectric layer. In one embodiment, after deposition of the precursors and a purge step, the atomic layer deposition cycle includes a nitridation step that is followed by or overlapped by an oxidation step.

Claims

1. A method for creating a dielectric, comprising:

(a) introducing a first precursor into a chamber having said substrate in said chamber;

(b) purging said chamber;

(c) introducing a nitriding agent into said chamber after said purging;

(d) introducing an oxidizing agent into said chamber, said introducing said oxidizing agent is started after starting said introducing said nitriding agent; and

(e) purging said chamber.

2. A method according to claim 1, wherein:

said nitriding agent is introduced at a higher concentration than said oxidizing agent.

3. A method according to claim 1, wherein:

said introducing an oxidizing agent is completed prior to completing said introducing a nitriding agent.

4. A method according to claim 1, wherein:

said introducing an oxidizing agent is started subsequent to completing said introducing a nitriding agent.

5. A method according to claim 1, wherein:

step (a) includes co-injecting said first precursor and a second precursor.

6. A method according to claim 5, wherein:

a resultant substance is created as a result of said steps (a)-(e);

said resultant substance includes a first component and a second component;

said first component is based on said first precursor;

said second component is based on said second precursor; and

said steps (a)-(e) are repeated for multiple iterations, each iteration includes varying said first precursor and said second precursor so that said first component and said second component having varying mole fractions as a function of depth in said dielectric region in order to create a crested bottom of a conduction band profile for said dielectric region.

7. A method according to claim 6, wherein:

said first component includes Hf; and

said second component includes Si.

8. A method according to claim 1, wherein:

a resultant substance is created as a result of said steps (a)-(e);

said resultant substance includes an oxygen component and a nitrogen component; and

said steps (a)-(e) are repeated for multiple iterations, each iteration includes varying steps (c) and (d) so that said oxygen component and said nitrogen component having varying mole fractions as a function of depth in said dielectric region.

9. A method according to claim 1, further comprising:

providing a substrate, said steps (a)-(e) add said dielectric to said substrate;

adding a floating gate structure on said dielectric region;

adding a second dielectric adjacent said floating gate; and

adding a control gate adjacent to said second dielectric.

10. A method according to claim 1, wherein:

step (a) includes co-injecting said first precursor and a second precursor;

said first precursor includes Hf;

said second precursor includes Si; and

HfSiON is created as a result of said steps (a)-(e).

11. A method according to claim 1, wherein:

said dielectric region created by steps (a)-(e) is a high-K dielectric region.

12. A method for creating a dielectric on a substrate, comprising:

(a) introducing a first precursor into a chamber having said substrate in said chamber, said first precursor includes a first component;

(b) introducing one or more nitriding agents into said chamber after said introducing said first precursor, said introducing said one or more nitriding agents is performed for a first time period; and

(c) introducing one or more oxidizing agents into said chamber, said introducing said one or more oxidizing agents is performed for a second time period, said second time period is shorter than said first time period.

13. A method according to claim 12, wherein:

step (a) includes co-injecting said first precursor and a second precursor into said chamber.

14. A method according to claim 12, wherein:

said nitriding agents are introduced at a higher concentration than said oxidizing agents.

15. A method according to claim 12, wherein:

said second time period at least partially overlaps with said first time period.

16. A method according to claim 15, wherein:

said second time period starts after said first time period starts; and

said second time period ends before said first time period ends.

17. A method according to claim 12, wherein:

said second time period starts after said first time period ends.

18. A method according to claim 17, further comprising:

introducing one or more nitriding agents into said chamber during a third time period after said second time period.

19. A method according to claim 12, wherein:

a resultant substance is created as a result of said steps (a)-(c);

said step (a) includes introducing a second precursor into said chamber, said second precursor includes a second component;

said resultant substance includes said first component and said second component; and

said steps (a)-(c) are repeated for multiple iterations, each iteration includes varying said first precursor and said second precursor so that said first component and said second component having varying mole fractions as a function of depth in said dielectric in order to create a crested bottom of a conduction band profile for said dielectric.

20. A method according to claim 19, wherein:

said first component includes Hf; and

said second component includes Si.

21. A method according to claim 12, wherein:

a resultant substance is created as a result of said steps (a)-(c);

said resultant substance includes an oxygen component and a nitrogen component; and

said steps (a)-(c) are repeated for multiple iterations, each iteration includes varying steps (b) and (c) so that said oxygen component and said nitrogen component having varying mole fractions as a function of depth in said dielectric region.

22. A method according to claim 12, further comprising:

purging said chamber after step (a).

23. A method according to claim 12, further comprising:

purging said chamber after step (c).

24. A method according to claim 23, further comprising:

purging said chamber after step (a).

25. A method for creating a dielectric, comprising:

co-injecting two materials into a chamber having a substrate in said chamber;

purging said chamber;

co-injecting one or more nitriding agents and an oxidizing agent into said chamber after said purging, said co-injecting includes injecting said one or more nitriding agents longer than injecting said oxidizing agent.

26. A method according to claim 25, further comprising:

purging said chamber after said co-injecting two materials.

27. A method according to claim 25, further comprising:

purging said chamber after said co-injecting one or more nitriding agents and an oxidizing agent.

28. A method according to claim 27, further comprising:

purging said chamber after said co-injecting two materials.

29. A method according to claim 25, wherein:

said nitriding agents are introduced at a higher concentration than said oxidizing agents.

30. A method according to claim 25, wherein:

said co-injecting two materials is repeated with iterations that vary mole fractions of said two materials as a function of depth in said dielectric region in order to create a crested bottom of a conduction band profile for said dielectric region.

31. A method according to claim 25, wherein:

said co-injecting one or more nitriding agents and an oxidizing agent is repeated with iterations that vary mole fractions of said one or more nitriding agents and said oxidizing agent as a function of depth in said dielectric region.

32. A method according to claim 25, wherein said co-injecting one or more nitriding agents and an oxidizing agent comprises:

injecting said one or more nitriding agents; and

injecting said oxidizing agent subsequent to completing said injecting said one or more nitriding agents.

33. A method according to claim 25, wherein said co-injecting one or more nitriding agents and an oxidizing agent comprises:

injecting said one or more nitriding agents; and

injecting said oxidizing agent while injecting said one or more nitriding agents.

34. A method according to claim 25, wherein said co-injecting one or more nitriding agents and an oxidizing agent comprises:

performing a first injection of said one or more nitriding agents;

injecting said oxidizing agent subsequent completing said first injection of said one or more nitriding agents; and

performing a second injection of said one or more nitriding agents after injecting said oxidizing agent.

35. A method for creating a dielectric, comprising:

(a) introducing a first precursor into a chamber having said substrate in said chamber, said first precursor includes at least a first material;

(b) purging said chamber after introducing said first precursor;

(c) performing a nitridation process in said chamber after said purging said chamber after introducing said first precursor;

(d) performing an oxidation process in said chamber, said oxidation process is performed at a lower concentration than said nitridation process; and

(e) purging said chamber.

36. A method according to claim 35, wherein:

step (a) includes co-injecting a first precursor and a second precursor;

37. A method according to claim 36, wherein:

a resultant substance is created as a result of said steps (a)-(e);

said resultant substance includes a first component based on said first precursor and a second component based on said second precursor; and

said steps (a)-(e) are repeated for multiple iterations, each iteration includes varying said first precursor and said second precursor so that said first component and said second component having varying mole fractions as a function of depth in said dielectric region in order to create a crested bottom of a conduction band profile for said dielectric region.

38. A method according to claim 35, wherein:

a resultant substance is created as a result of said steps (a)-(e);

said resultant substance includes an oxygen component and a nitrogen component; and

said steps (a)-(e) are repeated for multiple iterations, each iteration includes varying steps (c) and (d) so that said oxygen component and said nitrogen component having varying mole fractions as a function of depth in said dielectric region.