Lanthanide oxide / hafnium oxide dielectric layers

• US 7,192,824 B2
• Filed: 06/24/2003
• Issued: 03/20/2007
• Est. Priority Date: 06/24/2003
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Ahn, Kie Y., Forbes, Leonard
• Primary Examiner(s): Estrada; Michelle
• Assistant Examiner(s): Toledo; Fernando L.
• Application Number:
  US10/602,323
• Publication Number:
  US 20050020017A1
• Time in Patent Office: 1,365 Days
• Field of Search: 438/216, 438/761, 438/763, 438/778, 438/785
• US Class Current: 438/216
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• 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 21/022 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 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/02269 deposition by thermal evaporation H01L21/02293 takes precedence
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• 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 21/28211 in a gaseous ambient using an oxygen or a water vapour, e.g. RTO, possibly through a layer H01L21/28194 and H01L21/28202 take 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 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence
• CPC Class Codes: H01L 21/31645 Deposition of Hafnium oxides, e.g. HfO2
• CPC Class Codes: H01L 28/56 the dielectric comprising two or more layers, e.g. comprising buffer layers, seed layers, gradient layers
• CPC Class Codes: H01L 29/40114 the electrodes comprising a conductor-insulator-conductor-insulator-semiconductor structure
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• 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
• CPC Class Codes: H01L 29/78 : with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence
• CPC Class Codes: H01L 29/78657 : SOS transistors
• CPC Class Codes: H10B 12/03 : Making the capacitor or connections thereto
• CPC Class Codes: H10B 12/05 : Making the transistor

Abstract

Dielectric layers containing an atomic layer deposited hafnium oxide and an electron beam evaporated lanthanide oxide and a method of fabricating such a dielectric layer produce a reliable dielectric layer having an equivalent oxide thickness thinner than attainable using SiO₂. Forming a layer of hafnium oxide by atomic layer deposition and forming a layer of a lanthanide oxide by electron beam evaporation, where the layer of hafnium oxide is adjacent and in contact with the layer of lanthanide, provides a dielectric layer with a relatively high dielectric constant as compared with silicon oxide. The dielectric can be formed as a nanolaminate of hafnium oxide and a lanthanide oxide.

Claims

1. A method comprising:

forming a dielectric layer, the dielectric layer having a layer of hafnium oxide and a layer of a lanthanide oxide, including;

forming the layer of hafnium oxide by atomic layer deposition; and

forming the layer of a lanthanide oxide by electron beam evaporation,

wherein the layer of hafnium oxide is in contact with the layer of lanthanide oxide.

2. The method of claim 1, wherein the method further includes forming the layer of hafnium oxide on a substrate and forming the layer of lanthanide oxide on the layer of hafnium oxide.

3. The method of claim 1, wherein the method further includes forming the layer of lanthanide oxide on a substrate and forming the layer of hafnium oxide on the layer of lanthanide oxide.

4. The method of claim 1, wherein the method further includes controlling the forming of the layer of hafnium oxide and the forming of the layer of the lanthanide oxide to form a lanthanide oxide/hafnium oxide nanolaminate.

5. The method of claim 1, wherein the method further includes limiting a combined thickness of lanthanide oxide layers to between about 2 nanometers and about 10 nanometers.

6. The method of claim 1, wherein the method further includes limiting a combined thickness of hafnium oxide layers to a thickness between about 2 nanometers and about 10 nanometers.

7. The method of claim 1, wherein the method further includes forming multiple layers of lanthanide oxide, each layer of lanthanide oxide limited to a thickness between about 2 nanometers and about 10 nanometers.

8. The method of claim 1, wherein forming a layer of a lanthanide oxide includes forming an oxide selected from Pr₂O₃, Nd₂O₃, Sm₂O₃, Gd₂O₃, and Dy₂O₃.

9. The method of claim 1, wherein the method further includes maintaining the substrate at a temperature ranging from about 100°

C. to about 150°

C.

16. The method of claim 1, wherein forming the dielectric layer includes forming the dielectric layer in a capacitor.

17. The method of claim 1, wherein forming the dielectric layer includes forming the dielectric layer on a body region between a source and a drain in a transistor.

18. The method of claim 1, wherein forming the dielectric layer includes forming the dielectric layer on a body region between a source and a drain in a transistor in a memory.

19. The method of claim 1, wherein forming the dielectric layer includes forming the dielectric layer at least one of a controller and a device coupled to the controller in an electronic system.

10. A method of forming a dielectric layer comprising:

forming a layer of hafnium oxide by atomic layer deposition; and

forming a layer of a lanthanide oxide by electron beam evaporation, wherein the layer of hafnium oxide is in contact with the layer of lanthanide oxide, wherein the method further includes adding oxygen during the electron beam evaporation of the layer of lanthanide oxide.

11. A method comprising:

forming a dielectric layer, the dielectric layer having a layer of hafnium oxide and a layer of a lanthanide oxide, including;

forming the layer of hafnium oxide on a substrate by atomic layer deposition using a HfI₄ precursor; and

forming the layer of a lanthanide oxide on the layer of hafnium oxide by electron beam evaporation.

12. The method of claim 11, wherein the method further includes controlling the forming of the layer of hafnium oxide and the forming of the layer of the lanthanide oxide to form a lanthanide oxide/hafnium oxide nanolaminate.

13. The method of claim 11, wherein the method further includes limiting a combined thickness of lanthanide oxide layers to a thickness between about 2 nanometers and about 10 nanometers.

14. The method of claim 11, wherein forming a layer of a lanthanide oxide includes forming an oxide selected from Pr₂O₃, Nd₂O₃, Sm₂O₃, Gd₂O₃, and Dy₂O₃.

15. The method of claim 11, wherein the method further includes maintaining the substrate at a temperature ranging from about 100°

C. to about 150°

C.

20. A method of forming a capacitor, comprising:

forming a first conductive layer on a substrate;

forming a dielectric layer on the first conductive layer, the dielectric layer having a layer of hafnium oxide and a layer of a lanthanide oxide; and

forming a second conductive layer on the dielectric layer, wherein forming the dielectric layer includes;

forming the layer of hafnium oxide on the first conductive layer by atomic layer deposition using a HfI₄ precursor; and

forming the layer of a lanthanide oxide on the layer of hafnium oxide by electron beam evaporation, wherein the layer of lanthanide oxide is limited to between about 2 nanometers and about 10 nanometers.

21. The method of claim 20, wherein the method further includes controlling the forming of the layer of hafnium oxide and the forming of the layer of the lanthanide oxide on the layer of hafnium to form a lanthanide oxide/hafnium oxide nanolaminate.

22. The method of claim 20, wherein forming a layer of a lanthanide oxide includes forming an oxide selected from Pr₂O₃, Nd₂O₃, Sm₂O₃, Gd₂O₃, and Dy₂O₃.

23. The method of claim 20, wherein the method further includes maintaining the substrate at a temperature ranging from about 100°

C. to about 150°

C.

24. A method of forming a transistor comprising:

forming a source region and a drain region in a substrate, the source region and the drain region separated by a body region;

forming a dielectric layer on the body region between the source and drain regions, the dielectric layer containing a nanolaminate of hafnium oxide and a lanthanide oxide; and

coupling a gate to the dielectric layer, wherein forming the nanolaminate includes;

forming the layer of hafnium oxide by atomic layer deposition; and

forming the layer of a lanthanide oxide by electron beam evaporation, wherein the layer of hafnium oxide is in contact with the layer of lanthanide oxide.

25. The method of claim 24, wherein the method further includes limiting a combined thickness of lanthanide oxide layers to a thickness between about 2 nanometers and about 10 nanometers.

26. The method of claim 24, wherein the method further includes forming multiple layers of lanthanide oxide, each layer limited to a thickness of lanthanide oxide layers to between about 2 nanometers and about 10 nanometers.

27. The method of claim 24, wherein forming a layer of a lanthanide oxide includes forming an oxide selected from Pr₂O₃, Nd₂O₃, Sm₂O₃, Gd₂O₃, and Dy₂O₃.

28. The method of claim 24, wherein forming a layer of a hafnium oxide by atomic layer deposition includes using a hafnium halide as a precursor.

29. The method of claim 24, wherein the method further includes maintaining the substrate at a temperature ranging from about 100°

C. to about 150°

C.

30. The method of claim 24, wherein the method further includes adding oxygen during the electron beam evaporation of the layer of lanthanide oxide.

31. A method of forming a memory comprising:

forming a number of access transistors including forming a dielectric layer on a body region in a substrate between a source region and a drain region, the dielectric layer having a layer of hafnium oxide and a layer of a lanthanide oxide; and

forming a number of word lines, each word line coupled to one of the number of access transistors, wherein forming the dielectric layer includes;

forming the layer of hafnium oxide on the body region by atomic layer deposition; and

forming the layer of a lanthanide oxide on the layer of hafnium oxide by electron beam evaporation, wherein the layer of hafnium oxide is in contact with the layer of lanthanide oxide.

32. The method of claim 31, wherein the method further includes limiting a combined thickness of lanthanide oxide layers to between about 2 nanometers and about 10 nanometers and limiting a combined thickness of hafnium oxide layers to between about 2 nanometers and about 10 nanometers.

33. The method of claim 31, wherein the method further includes forming multiple layers of lanthanide oxide, each layer limited to a thickness of lanthanide oxide layers to between about 2 nanometers and about 10 nanometers.

34. The method of claim 31, wherein forming a layer of a lanthanide oxide includes forming an oxide selected from Pr₂O₃, Nd₂O₃, Sm₂O₃, Gd₂O₃, and Dy₂O₃.

35. The method of claim 31, wherein forming a layer of a hafnium oxide by atomic layer deposition includes using a hafnium halide as a precursor.

36. The method of claim 31, wherein the method further includes maintaining the substrate at a temperature ranging from about 100°

C. to about 150°

C.

37. The method of claim 31, wherein the method further includes adding oxygen during the electron beam evaporation of the layer of lanthanide oxide.

38. A method of forming an electronic system comprising:

providing a controller; and

coupling a device to the controller, wherein at least one of the controller and the device includes a dielectric layer having a nanolaminate of hafnium oxide and a lanthanide oxide, wherein forming the nanolaminate includes;

forming the layer of hafnium oxide by atomic layer deposition; and

forming the layer of a lanthanide oxide by electron beam evaporation, wherein the

layer of hafnium oxide is in contact with the layer of lanthanide oxide.

39. The method of claim 38, wherein the method further includes limiting a combined thickness of lanthanide oxide layers to between about 2 nanometers and about 10 nanometers.

40. The method of claim 38, wherein the method further includes limiting a combined thickness of hafnium oxide layers to between about 2 nanometers and about 10 nanometers.

41. The method of claim 38, wherein the method further includes forming multiple layers of lanthanide oxide, each layer limited to a thickness of lanthanide oxide layers to between about 2 nanometers and about 10 nanometers.

42. The method of claim 38, wherein forming a layer of a lanthanide oxide includes forming an oxide selected from Pr₂O₃, Nd₂O₃, Sm₂O₃, Gd₂O₃, and Dy₂O₃.

43. The method of claim 38, wherein forming a layer of a hafnium oxide by atomic layer deposition includes using a hafnium halide as a precursor.

44. The method of claim 38, wherein the method further includes maintaining the substrate at a temperature ranging from about 100°

C. to about 150°

C.

45. The method of claim 38, wherein the method further includes adding oxygen during the electron beam evaporation of the layer of lanthanide oxide.