Method of fabricating piezoelectric material with selected c-axis orientation

Patent metadata

Field	Value
Publication number	US-9243316-B2
Application number	US-69210810-A
Country	US
Kind code	B2
Filing date	Jan 22, 2010
Priority date	Jan 22, 2010
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

In accordance with a representative embodiment, a method of fabricating a piezoelectric material comprising a first component and a second component comprises: providing a substrate; flowing hydrogen over the substrate; flowing the first component to form the piezoelectric material over a target; and sputtering the piezoelectric material from the target on the substrate. In accordance with another representative embodiment, a method of fabricating a bulk acoustic wave (BAW) resonator comprises: forming a first electrode over a substrate; forming a seed layer over the substrate; and depositing a piezoelectric material having a compression-negative (C N ) polarity. The depositing of the piezoelectric material comprises: flowing a first component of the piezoelectric material to form the piezoelectric material over a target comprising a second component of the piezoelectric material; and sputtering the piezoelectric material from the target to the substrate.

First claim

The invention claimed is:

1. A method of fabricating a piezoelectric material comprising a first component and a second component, the method comprising:
providing a substrate;
initially flowing hydrogen over the substrate;
after the initially flowing of the hydrogen over the substrate,
flowing the first component to form the piezoelectric material over a surface of a target comprising the second component;
sputtering the piezoelectric material from the target onto the substrate; and
flowing the hydrogen over the substrate during the sputtering at a rate sufficient to cause a piezoelectric film having a defined polarity to be formed over the substrate, wherein
a seed layer is not formed over the substrate prior to the sputtering.

2. A method of fabricating a piezoelectric material as claimed in claim 1 , wherein the piezoelectric film comprises a compression-negative (C N ) polarity.

3. A method of fabricating a piezoelectric material as claimed in claim 1 , wherein the flowing of hydrogen is continuous during the fabricating of the piezoelectric film.

4. A method of fabricating a piezoelectric material as claimed in claim 1 , further comprising, after the depositing:
ceasing flow of the hydrogen;
forming a second substrate over the piezoelectric film; and
sputtering the piezoelectric material from the target over the second substrate.

5. A method of fabricating a piezoelectric material as claimed in claim 4 , further comprising, before forming the second substrate flowing hydrogen over the second substrate, wherein the piezoelectric material comprises a compression-negative (C N ) material.

6. A method of fabricating a piezoelectric material as claimed in claim 3 , wherein the substrates comprise a metal.

7. A method of fabricating a piezoelectric material as claimed in claim 6 , wherein the metal comprises one of: molybdenum (Mo), aluminum (Al), tungsten (W), platinum (Pt), and ruthenium (Ru).

8. A method of fabricating a piezoelectric material as claimed in claim 1 , wherein the first component comprises nitrogen and the second component comprises aluminum.

9. A method of fabricating a piezoelectric material as claimed in claim 4 , wherein the piezoelectric material sputtered on the first substrate comprises a compression-negative (C N ) material, and the piezoelectric material sputtered over the second substrate comprises a compression-positive (C P ) material.

10. A method of fabricating a piezoelectric material as claimed in claim 1 , wherein the flowing of hydrogen during the depositing forms NH x .

11. A method of fabricating a bulk acoustic wave (BAW) resonator having a piezoelectric material consisting essentially of first and second components, the method comprising:
forming a first electrode over a substrate;
forming a seed layer consisting essentially of the second component over the substrate;
flowing the first component of the piezoelectric material to form the piezoelectric material over a surface of a target consisting essentially of the second component of the piezoelectric material; and
sputtering the piezoelectric material from the target onto the seed layer to deposit a piezoelectric layer having a compression-negative (C N ) polarity.

12. A method as of fabricating a BAW resonator as claimed in claim 11 , further comprising forming a second electrode over the piezoelectric material.

13. A method as of fabricating a BAW resonator as claimed in claim 11 , wherein the seed layer comprises aluminum.

14. A method of fabricating a BAW resonator as claimed in claim 13 , wherein the first electrode and the second electrode comprise one of molybdenum (Mo), aluminum (Al), tungsten (W), platinum (Pt), and ruthenium (Ru).

15. A method of fabricating a BAW resonator as claimed in claim 11 , further comprising, after the forming of the first electrode and before the forming of the seed layer, forming a plasma and removing a contaminant from a surface of the first electrode.

16. A method of fabricating a BAW resonator as claimed in claim 11 , further comprising, after the forming of the seed layer, maintaining a flow of an inert gas over the surface of the seed layer during the depositing of the first component and the piezoelectric material.

17. A method of fabricating a BAW resonator as claimed in claim 12 , further comprising, after the depositing of the piezoelectric material: sputtering a second piezoelectric material over the second electrode, wherein the second piezoelectric material comprises a compression-positive (C P ) polarity.

18. A method of fabricating a BAW resonator as claimed in claim 12 , wherein the first electrode and the second electrode comprise a metal.

19. A method of fabricating a BAW resonator as claimed in claim 18 , wherein the metal comprises one of: molybdenum (Mo), aluminum (Al), tungsten (W), platinum (Pt), and ruthenium (Ru).

20. A method of fabricating a BAW resonator as claimed in claim 11 , wherein the first component comprises nitrogen and the second component comprises aluminum.

21. A method of fabricating a BAW resonator as claimed in claim 11 , wherein the seed layer is selected to foster growth of the piezoelectric material comprising the compression-negative (C N ) polarity.

22. A method of fabricating a BAW resonator as claimed in claim 11 , wherein vacuum is maintained during the method.

23. The method of claim 11 , wherein the first component is nitrogen (N) and the second component is aluminum (Al).

Assignees

• Larson Iii John
• Mishin Sergey
• Avago Technologies General Ip

Inventors

• Larson Iii John
• Mishin Sergey

Classifications

• C23C14/0617 Primary

  AIII BV compounds, where A is Al, Ga, In or Tl and B is N, P, As, Sb or Bi · CPC title

• C23C14/345

  using substrate bias · CPC title

• C23C14/022

  by means of bombardment with energetic particles or radiation · CPC title

• C23C14/228

  Gas flow assisted PVD deposition · CPC title

• C23C14/0641

  Nitrides (C23C14/0617 takes precedence) · CPC title