Graded dielectric layers

• US 8,110,469 B2
• Filed: 08/30/2005
• Issued: 02/07/2012
• Est. Priority Date: 08/30/2005
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Gealy, Dan, Bhat, Vishwanath, Srividya, Cancheepuram V., Rocklein, M. Noel
• Primary Examiner(s): Lindsay, Jr., Walter L
• Assistant Examiner(s): POMPEY, RON EVERETT
• Application Number:
  US11/216,542
• Publication Number:
  US 20070048953A1
• Time in Patent Office: 2,352 Days
• Field of Search: 438/287, 438/591, 438/763, 438/785, 438/786, 257/E21.29, 257/E21.625, 257/E21.639
• US Class Current: 438/287
• CPC Class Codes: C23C 16/45529 specially adapted for making a layer stack of alternating different compositions or gradient compositions
• CPC Class Codes: H01L 21/02148 the material containing hafnium, e.g. HfSiOx or HfSiON
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• 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 21/0228 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 21/31641 Deposition of Zirconium oxides, e.g. ZrO2
• CPC Class Codes: H01L 21/31645 Deposition of Hafnium oxides, e.g. HfO2
• CPC Class Codes: H01L 28/40 Capacitors
• 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 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence

Abstract

Graded dielectric layers and methods of fabricating such dielectric layers provide dielectrics in a variety of electronic structures for use in a wide range of electronic devices and systems. In an embodiment, a dielectric layer is graded with respect to a doping profile across the dielectric layer. In an embodiment, a dielectric layer is graded with respect to a crystalline structure profile across the dielectric layer. In an embodiment, a dielectric layer is formed by atomic layer deposition incorporating sequencing techniques to generate a doped dielectric material.

Claims

1. A method comprising:

controlling a doping profile of a dopant in a metal oxide across the metal oxide to form a graded metal oxide in an integrated circuit, the metal oxide having a top surface and a bottom surface, such that the graded metal oxide has varying amounts of the dopant across the graded metal oxide between the top and bottom surfaces with concentrations of the dopant at the top surface and at the bottom surface being greater than a concentration of the dopant in a center of the metal oxide between the top surface and the bottom surface, the graded metal oxide formed substantially as monolayers across the graded metal oxide having a base metal oxide composition that is doped and not altered into an undoped base composition that includes the dopant.

2. The method of claim 1, wherein forming a graded metal oxide includes forming the graded metal oxide by atomic layer deposition.

3. The method of claim 1, wherein forming a graded metal oxide includes forming a metal oxide doped with silicon such that the metal oxide doped with silicon does not form a silicate compound and the concentration of the silicon in the metal oxide has its largest value at an interface of the graded metal oxide with another material.

4. The method of claim 3, wherein the method includes forming the material as a top layer disposed on the graded dielectric layer.

5. The method of claim 1, wherein forming a graded metal oxide includes forming a metal oxide doped with a dopant metal such that concentration of the dopant metal in the metal oxide has its largest value at an interface of the graded dielectric layer with another material.

6. The method of claim 1, wherein forming a graded metal oxide in an integrated circuit includes forming the graded metal oxide as a dielectric in a capacitor.

7. The method of claim 6, wherein forming the graded metal oxide as a dielectric in a capacitor includes forming the graded metal oxide on a bottom TiN electrode.

8. The method of claim 6, wherein forming the graded metal oxide as a dielectric in a capacitor includes forming the graded metal oxide on a bottom TaN electrode.

9. The method of claim 1, wherein forming a graded metal oxide in an integrated circuit includes forming the graded metal oxide as a dielectric layer in a transistor.

10. The method of claim 1, wherein forming a graded metal oxide in an integrated circuit includes forming the graded metal oxide as a nanolaminate.

11. The method of claim 1, wherein forming a graded metal oxide in an integrated circuit includes forming the graded metal oxide as a dielectric layer in a memory device.

12. The method of claim 10, wherein the method includes forming connections to couple the integrated circuit to components of an electronic system.

13. The method of claim 1, wherein the method includes forming the graded metal oxide doped with silicon.

14. The method of claim 13, wherein forming the graded metal oxide doped with silicon includes forming a layer of hafnium oxide doped with silicon.

15. The method of claim 14, wherein forming the layer of hafnium oxide doped with silicon includes forming the layer of hafnium oxide doped with silicon by atomic layer deposition.

16. The method of claim 14, wherein forming a layer of hafnium oxide doped with silicon includes forming the layer of hafnium oxide doped with silicon by atomic layer deposition including forming quantized levels in the layer using hafnium oxide and silicon oxide depositions.

17. The method of claim 14, wherein forming the layer of hafnium oxide doped with silicon includes forming a nanolaminate having hafnium oxide layers with varying silicon content.

18. The method of claim 14, wherein forming the layer of hafnium oxide doped with silicon includes forming the layer of hafnium oxide doped with silicon having a silicon to hafnium ratio ranging from about 1:

1 at the interface of the layer with another material to about 1;

15 at the interface of the layer with the other material.

19. The method of claim 14, wherein forming the layer of hafnium oxide doped with silicon includes forming the layer of hafnium oxide having a silicon to hafnium ratio less than 1:

21 at a region interior to the layer of hafnium oxide.

20. The method of claim 14, wherein forming the layer of hafnium oxide doped with silicon includes forming the layer as a dielectric between two electrodes of a capacitor such that, at each interface of the layer with the two electrodes, the layer of hafnium oxide doped with silicon has a silicon to hafnium ratio ranging from about 1:

1 to about 1;

15.

21. The method of claim 14, wherein forming the layer of hafnium oxide doped with silicon includes forming the layer as a dielectric between a top electrode and a bottom electrode of a capacitor such that, at an interface of the layer with the top electrode, the layer of hafnium oxide doped with silicon has a silicon to hafnium ratio ranging from about 1:

1 to about 1;

15.

22. The method of claim 13, wherein forming the metal oxide layer doped with silicon includes forming a layer of zirconium oxide doped with silicon.

23. The method of claim 22, wherein forming the layer of zirconium oxide doped with silicon includes forming the layer of zirconium oxide doped with silicon by atomic layer deposition.

24. The method of claim 22, wherein forming a layer of zirconium oxide doped with silicon includes forming the layer of zirconium oxide doped with silicon by atomic layer deposition including forming quantized levels in the layer using zirconium oxide and silicon oxide depositions.

25. The method of claim 22, wherein forming the layer of zirconium oxide doped with silicon includes forming a nanolaminate having zirconium oxide layers with varying silicon content.

26. The method of claim 22, wherein forming the layer of zirconium oxide doped with silicon includes forming the layer of zirconium oxide doped with silicon having a silicon to zirconium ratio ranging from about 1:

1 at the interface of the layer with another material to about 1;

15 at the interface of the layer with the other material.

27. The method of claim 22, wherein forming the layer of zirconium oxide doped with silicon includes forming the layer of zirconium oxide having a silicon to zirconium ratio less than 1:

21 at a region interior to the layer of zirconium oxide.

28. The method of claim 22, wherein forming the layer of zirconium oxide doped with silicon includes forming the layer as a dielectric between two electrodes of a capacitor such that, at each interface of the layer with the two electrodes, the layer of zirconium oxide doped with silicon has a silicon to zirconium ratio ranging from about 1:

1 to about 1;

15.

29. The method of claim 22, wherein forming the layer of zirconium oxide doped with silicon includes forming the layer as a dielectric between a top electrode and a bottom electrode of a capacitor such that, at an interface of the layer with the top electrode, the layer of zirconium oxide doped with silicon has a silicon to zirconium ratio ranging from about 1:

1 to about 1;

15.

30. The method of claim 1, wherein controlling a doping profile of the dopant in the metal oxide between the top and bottom surfaces includes forming the graded metal oxide such that the doping profile approximates a parabolic shape with a minimum of the dopant being in a center region of the graded dielectric layer between the top surface and the bottom surface.

31. The method of claim 14, wherein the method includes forming the hafnium oxide doped with silicon with an effective permittivity increased by about one-third relative to a silicon hafnium oxide having a uniform silicon content.