Atomic layer-deposited hafnium aluminum oxide

• US 7,135,421 B2
• Filed: 06/05/2002
• Issued: 11/14/2006
• Est. Priority Date: 06/05/2002
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Ahn, Kie Y., Forbes, Leonard
• Primary Examiner(s): Ghyka, Alexander
• Application Number:
  US10/163,481
• Publication Number:
  US 20030227033A1
• Time in Patent Office: 1,623 Days
• Field of Search: 438/585, 438/758, 438/785
• US Class Current: 438/785
• CPC Class Codes: H01L 21/28176 with a treatment, e.g. annealing, after the formation of the definitive gate conductor
• 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 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• 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 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material

Abstract

A dielectric film containing HfAlO₃ and a method of fabricating such a dielectric film produce a reliable gate dielectric having an equivalent oxide thickness thinner than attainable using SiO₂. A gate dielectric is formed by atomic layer deposition employing a hafnium sequence and an aluminum sequence. The hafnium sequence uses HfCl₄ and water vapor. The aluminum sequence uses either trimethylaluminum, Al(CH₃)₃, or DMEAA, an adduct of alane (AlH₃) and dimethylethylamine [N(CH₃)₂(C₂H₅)], with distilled water vapor. These gate dielectrics containing a HfAlO₃ film are thermodynamically stable such that the HfAlO₃ film will have minimal reactions with a silicon substrate or other structures during processing.

Claims

1. A method of forming a dielectric film comprising:

forming a layer of hafnium aluminum oxide by atomic layer deposition including;

pulsing a hafnium containing precursor into a reaction chamber containing a substrate, the reaction chamber substantially without another reactant precursor during the pulsing of the hafnium containing precursor, the hafnium containing precursor having a composition without aluminum; and

pulsing an aluminum containing precursor into the reaction chamber, the reaction chamber substantially without another reactant precursor during the pulsing of the aluminum containing precursor, the aluminum containing precursor having a composition without hafnium, wherein pulsing the hafnium containing precursor and pulsing the aluminum containing precursor is performed during an atomic layer deposition cycle to form hafnium aluminum oxide and after pulsing the hafnium containing precursor and after pulsing the aluminum containing precursor the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber.

2. The method of claim 1, wherein the method includes controlling a number of cycles of pulsing the hafnium containing precursor and a number of cycles of pulsing the aluminum containing precursor to include a predetermined amount of hafnium oxide in the layer of hafnium aluminum oxide.

3. The method of claim 1, wherein pulsing a hafnium containing precursor into a reaction chamber is followed by pulsing a first oxygen containing precursor into the reaction chamber.

4. The method of claim 1, wherein pulsing an aluminum containing precursor into the reaction chamber is followed by pulsing a second oxygen containing precursor into the reaction chamber.

5. The method of claim 1, wherein pulsing each precursor into the reaction chamber is controlled for a predetermined period, the predetermined period being individually controlled for each precursor pulsed into the reaction chamber.

6. The method of claim 1, wherein the method further includes maintaining the substrate at a selected temperature for each pulsing of a precursor, the selected temperature set independently for pulsing each precursor.

7. The method of claim 1, wherein each pulsing of a precursor is followed by purging the reaction chamber with a purging gas.

8. The method of claim 1, wherein the method further includes repeating for a number of cycles the pulsing of the hafnium containing precursor, and the aluminum containing precursor.

52. The method of claim 1, wherein the method includes forming the layer of hafnium aluminum oxide as an amorphous layer.

9. A method of forming a dielectric film comprising:

forming a layer of hafnium aluminum oxide by atomic layer deposition including;

pulsing a hafnium containing source gas into a reaction chamber containing a substrate, the reaction chamber substantially without another reactant gas during the pulsing of the hafnium containing source gas, the hafnium containing source gas having a composition without aluminum;

pulsing a first oxygen containing source gas into the reaction chamber;

pulsing an aluminum containing source gas into the reaction chamber, the reaction chamber substantially without another reactant gas during the pulsing of the aluminum containing source gas, the aluminum containing source gas having a composition without hafnium; and

pulsing a second oxygen containing source gas into the reaction chamber, wherein pulsing the hafnium containing source gas and pulsing the aluminum containing source gas is performed during an atomic layer deposition cycle to form hafnium aluminum oxide and after each pulsing, the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber.

10. The method of claim 9, wherein pulsing a first oxygen containing source gas includes pulsing water vapor.

11. The method of claim 9, wherein pulsing a second oxygen containing source gas includes pulsing distilled water vapor.

12. The method of claim 9, wherein pulsing a second oxygen containing source gas includes pulsing oxygen.

13. The method of claim 9, wherein the method further includes for each source gas independently controlling a pulsing period of time, a number of times the source is pulsed into the substrate, and a substrate temperature.

14. The method of claim 13, wherein the method further includes for each source gas independently controlling a pulsing period of time, a number of times the source is pulsed into the substrate, and a substrate temperature to form a dielectric film containing HfAlO_3, the dielectric film having a dielectric constant in the range from about 9 to about 25.

15. The method of claim 9, wherein the method further includes repeating for a number of cycles the pulsing of the hafnium containing source gas, the first oxygen containing source gas, the aluminum containing source gas, and the second oxygen containing source gas.

16. The method of claim 15, wherein repeating for a number of cycles the pulsing of the hafnium containing source gas, the first oxygen containing source gas, the aluminum containing source gas, and the second oxygen containing source gas is followed by annealing at a temperature ranging from about 300°

C. to about 800°

C.

17. The method of claim 14, wherein the forming the dielectric film containing HfAlO₃ includes forming an essentially HfAlO₃ film.

53. The method of claim 9, wherein the method includes forming the layer of hafnium aluminum oxide as an amorphous layer.

18. A method of forming a dielectric film comprising:

forming a layer of hafnium aluminum oxide by atomic layer deposition including;

pulsing a HfCl₄ source gas into a reaction chamber containing a substrate, the reaction chamber substantially without another reactant gas during the pulsing of the HfCl₄ source gas, the HfCl₄ source gas having a composition without aluminum;

pulsing a first oxygen containing source gas into the reaction chamber;

pulsing an aluminum containing source gas into the reaction chamber, the reaction chamber substantially without another reactant gas during the pulsing of the aluminum containing source gas, the aluminum containing source gas having a composition without hafnium; and

pulsing a second oxygen containing source gas into the reaction chamber, wherein pulsing the HfCl₄ source gas and pulsing the aluminum containing source gas is performed during an atomic layer deposition cycle to form hafnium aluminum oxide and after each pulsing, the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber.

19. The method of claim 18, wherein pulsing a HfCl₄ source gas into a reaction chamber is performed with the substrate maintained at a temperature ranging from about 350°

C. to about 550°

C.

20. The method of claim 18, wherein pulsing a HfCl₄ source gas into a reaction chamber is performed with the HfCl₄ source gas temperature ranging from about 130°

C. to about 154°

C.

21. The method of claim 18, wherein pulsing a first oxygen containing source gas into the reaction chamber is performed at a flow rate ranging from about 0.5 mPa m³/sec to about 1.0 mPa m³/sec.

22. The method of claim 18, wherein the method further includes for each source gas independently controlling a pulsing period of time, a number of times the source is pulsed into the substrate, and a substrate temperature.

23. The method of claim 22, wherein the method further includes for each source gas independently controlling a pulsing period of time, a number of times the source is pulsed into the substrate, and a substrate temperature to form a dielectric film containing HfAlO_3, the dielectric film having a dielectric constant in the range from about 9 to about 25.

54. The method of claim 18, wherein the method includes annealing the layer of hafnium aluminum oxide at a temperature ranging from about 300°

C. to about 800°

C.

24. A method of forming a dielectric film comprising:

forming a layer of hafnium aluminum oxide by atomic layer deposition including;

pulsing a hafnium containing source gas into a reaction chamber containing a substrate, the reaction chamber substantially without another reactant gas during the pulsing of the hafnium containing source gas, the hafnium containing source gas having a composition without aluminum;

pulsing a first oxygen containing source gas into the reaction chamber;

pulsing a trimethylaluminum source gas into the reaction chamber, the reaction chamber substantially without another reactant gas during the pulsing of the trimethylaluminum source gas, the trimethylaluminum source gas having a composition without hafnium; and

pulsing a second oxygen containing source gas into the reaction chamber, wherein pulsing the hafnium containing source gas and pulsing the trimethylaluminum source gas is performed during an atomic layer deposition cycle to form hafnium aluminum oxide and after each pulsing, the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber.

25. The method of claim 24, wherein pulsing the trimethylaluminum source gas into the reaction chamber is performed with the substrate maintained at a temperature ranging from about 350°

C. to about 370°

C.

26. The method of claim 25, wherein pulsing a trimethylaluminum source gas into the reaction chamber is performed at a pressure of about 230 mTorr.

27. The method of claim 24, wherein the method further includes for each source gas independently controlling a pulsing period of time, a number of times the source is pulsed into the substrate, and a substrate temperature.

28. The method of claim 27, wherein the method further includes for each source gas independently controlling a pulsing period of time, a number of times the source is pulsed into the substrate, and a substrate temperature to form a dielectric film containing HfAlO_3, the dielectric film having a dielectric constant in the range from about 9 to about 25.

55. The method of claim 24, wherein the method includes annealing the layer of hafnium aluminum oxide in an inert atmosphere.

29. A method of forming a dielectric film comprising:

forming a layer of hafnium aluminum oxide by atomic layer deposition including;

pulsing a hafnium containing source gas into a reaction chamber containing a substrate, the reaction chamber substantially without another reactant gas during the pulsing of the hafnium containing source gas, the hafnium containing source gas having a composition without aluminum;

pulsing a first oxygen containing source gas into the reaction chamber;

pulsing a DMEAA source gas into the reaction chamber, the reaction chamber substantially without another reactant gas during the pulsing of the DMEAA source gas, the DMEAA source gas having a composition without hafnium; and

pulsing a second oxygen containing source gas into the reaction chamber, wherein pulsing the hafnium containing source gas and pulsing the DMEAA source gas is performed during an atomic layer deposition cycle to form hafnium aluminum oxide and after each pulsing, the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber.

30. The method of claim 29, wherein pulsing a DMEAA source gas into the reaction chamber is performed with the substrate maintained at a temperature ranging from about 350°

C. to about 550°

C.

31. The method of claim 30, wherein pulsing a DMEAA source gas into the reaction chamber is performed at a pressure of about 30 mTorr.

32. The method of claim 29, wherein the method further includes for each source gas independently controlling a pulsing period of time, a number of times the source is pulsed into the substrate, and a substrate temperature.

33. The method of claim 32, wherein the method further includes for each source gas independently controlling a pulsing period of time, a number of times the source is pulsed into the substrate, and a substrate temperature to form a dielectric film containing HfAlO_3, the dielectric film having a dielectric constant in the range from about 9 to about 25.

56. The method of claim 29, wherein the method includes forming the layer of hafnium aluminum oxide as an amorphous layer.

34. A method of forming a dielectric film comprising:

forming a layer of hafnium aluminum oxide by atomic layer deposition including;

pulsing a HfCl₄ source gas into a reaction chamber containing a substrate, the reaction chamber substantially without another reactant gas during the pulsing of the HfCl₄ source gas, the HfCl₄ source gas having a composition without aluminum;

pulsing a first oxygen containing source gas into the reaction chamber;

pulsing a trimethylaluminum source gas into the reaction chamber, the reaction chamber substantially without another reactant gas during the pulsing of the trimethylaluminum source gas, the trimethylaluminum source gas having a composition without hafnium; and

pulsing a second oxygen containing source gas into the reaction chamber, wherein pulsing the HfCl₄ source gas and pulsing the trimethylaluminum source gas is performed during an atomic layer deposition cycle to form hafnium aluminum oxide and after each pulsing, the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber.

35. The method of claim 34, wherein pulsing a HfCl₄ source gas into a reaction chamber is followed by purging the reaction chamber with pure nitrogen.

36. The method of claim 34, wherein pulsing a trimethylaluminum source gas into the reaction chamber is followed by purging the reaction chamber with argon.

57. The method of claim 34, wherein the method includes annealing the layer of hafnium aluminum oxide in an inert atmosphere.

37. A method of forming a dielectric film comprising:

forming a layer of hafnium aluminum oxide by atomic layer deposition including;

pulsing a HfCl₄ source gas into a reaction chamber containing a substrate, the reaction chamber substantially without another reactant gas during the pulsing of the HfCl₄ source gas, the HfCl₄ source gas having a composition without aluminum;

pulsing a first oxygen containing source gas into the reaction chamber;

pulsing a DMEAA source gas into the reaction chamber, the reaction chamber substantially without another reactant gas during the pulsing of the DMEAA source gas, the DMEAA source gas having a composition without hafnium; and

pulsing a second oxygen containing source gas into the reaction chamber, wherein pulsing the HfCl₄ source gas and pulsing the DMEAA source gas is performed during an atomic layer deposition cycle to form hafnium aluminum oxide and after each pulsing, the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber.

38. The method of claim 37, wherein pulsing a HfCl₄ source gas into a reaction chamber is followed by purging the reaction chamber with pure nitrogen.

39. The method of claim 37, wherein pulsing a DMEAA source gas into the reaction chamber is followed by purging the reaction chamber with hydrogen.

58. The method of claim 37, wherein the method includes annealing the layer of hafnium aluminum oxide in a nitrogen atmosphere.

40. A method of forming a transistor comprising:

forming first and second source/drain regions in a substrate;

forming a body region between the first and second source/drain regions;

forming a film on the body region between the first and second source/drain regions, the film having a layer of hafnium aluminum oxide, the layer of hafnium aluminum oxide formed by atomic layer deposition; and

coupling a gate to the film, wherein forming the layer of hafnium aluminum oxide includes

pulsing a hafnium containing precursor into a reaction chamber containing the substrate, the reaction chamber substantially without another reactant precursor during the pulsing of the hafnium containing precursor, the hafnium containing precursor having a composition without aluminum;

pulsing a first oxygen containing precursor into the reaction chamber;

pulsing an aluminum containing precursor into the reaction chamber, the reaction chamber substantially without another reactant precursor during the pulsing of the aluminum containing precursor, the aluminum containing precursor having a composition without hafnium; and

pulsing a second oxygen containing precursor into the reaction chamber, wherein pulsing the hafnium containing precursor and pulsing the aluminum containing precursor is performed during an atomic layer deposition cycle to form hafnium aluminum oxide and after each pulsing, the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber.

41. The method of claim 40, wherein pulsing a hafnium containing precursor into a reaction chamber includes pulsing a HfCl₄ source gas into the reaction chamber.

42. The method of claim 40, wherein pulsing an aluminum containing precursor into the reaction chamber includes pulsing a DMEAA source gas into the reaction chamber.

43. The method of claim 40, wherein pulsing an aluminum containing precursor into the reaction chamber includes pulsing a trimethylaluminum source gas into the reaction chamber.

59. The method of claim 40, wherein the method includes forming the film substantially without a silicon oxide layer annealing the layer of hafnium aluminum oxide at a temperature ranging from about 300°

C. to about 800°

C.

44. A method of forming a memory array comprising:

forming a number of access transistors, at least one of the access transistors including a film containing HfAlO₃ on a body region between a first and second source/drain regions, the HfAlO₃ formed by atomic layer deposition including;

pulsing a hafnium containing source gas into a reaction chamber containing a substrate, the reaction chamber substantially without another reactant gas during the pulsing of the hafnium containing source gas, the hafnium containing source gas having a composition without aluminum;

pulsing a first oxygen containing source gas into the reaction chamber;

pulsing an aluminum containing source gas into a reaction chamber, the reaction chamber substantially without another reactant gas during the pulsing of the aluminum containing source gas, the aluminum containing source gas having a composition without hafnium; and

pulsing a second oxygen containing source gas into the reaction chamber, wherein pulsing the hafnium containing source gas and pulsing the aluminum containing source gas is performed during an atomic layer deposition cycle to form hafnium aluminum oxide and after each pulsing, the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber;

forming a number of word lines coupled to a number of the gates of the number of access transistors;

forming a number of source lines coupled to a number of the first source/drain regions of the number of access transistors; and

forming a number of bit lines coupled to a number of the second source/drain regions of the number of access transistors.

45. The method of claim 44, wherein pulsing a hafnium containing precursor into a reaction chamber includes pulsing a HfCl₄ source gas into the reaction chamber.

46. The method of claim 44, wherein pulsing an aluminum containing precursor into the reaction chamber includes pulsing a DMEAA source gas into the reaction chamber.

47. The method of claim 44, wherein pulsing an aluminum containing precursor into the reaction chamber includes pulsing a trimethylaluminum source gas into the reaction chamber.

60. The method of claim 44, wherein the method includes forming the layer of hafnium aluminum oxide as an amorphous layer.

48. A method of forming an electronic system comprising:

providing a processor;

coupling a memory array to the processor, wherein the memory array includes at least one access transistor having a film containing HfAlO₃ on a body region between a first and second source/drain regions, the HfAlO₃ formed by atomic layer deposition including;

pulsing a hafnium containing source gas into a reaction chamber containing a substrate, the reaction chamber substantially without another reactant gas during the pulsing of the hafnium containing source gas, the hafnium containing source gas having a composition without aluminum; and

pulsing an aluminum containing source gas into a reaction chamber, the reaction chamber substantially without another reactant gas during the pulsing of the aluminum containing source gas, the aluminum containing source gas having a composition without hafnium, wherein pulsing the hafnium containing source gas and pulsing the aluminum containing source gas is performed during an atomic layer deposition cycle to form hafnium aluminum oxide, and after pulsing the hafnium containing precursor and after pulsing the aluminum containing precursors, the reaction chamber is subjected to a process selected from a group consisting of evacuating the reaction chamber, purging the reaction chamber with a purging gas, and a combination of evacuating and purging the reaction chamber; and

forming a system bus that couples the processor to the memory array.

49. The method of claim 48, wherein pulsing a hafnium containing precursor into a reaction chamber includes pulsing a HfCl₄ source gas into the reaction chamber.

50. The method of claim 48, wherein pulsing an aluminum containing precursor into the reaction chamber includes pulsing a DMEAA source gas into the reaction chamber.

51. The method of claim 48, wherein pulsing an aluminum containing precursor into the reaction chamber includes pulsing a trimethylaluminum source gas into the reaction chamber.

61. The method of claim 48, wherein the method includes forming the layer of hafnium aluminum oxide as an amorphous layer.