Electronic device including langasite structure compound and method for making such devices

• US 20020015452A1
• Filed: 05/03/2001
• Published: 02/07/2002
• Est. Priority Date: 05/03/2000
• Status: Active Grant

• Current Assignee: Crystal Photonics Incorporated
• Original Assignee: Crystal Photonics Incorporated
• Inventors: Jen, Shen, Chai, Bruce H.T., Chou, Mitch M.C., Qiu, Haihong
• Granted Patent: US 6,455,986 B2
• Time in Patent Office: Days
• US Class Current: 375/316
• CPC Class Codes: H03H 9/02039 consisting of a material from the crystal group 32, e.g. langasite, langatate, langanite
• CPC Class Codes: H03H 9/0259 of langasite substrates
• CPC Class Codes: H03H 9/56 Monolithic crystal filters
• CPC Class Codes: H03H 9/64 using surface acoustic waves

Abstract

An electronic device includes a piezoelectric layer formed of an ordered Langasite structure compound having the formula A₃BC₃D₂E₁₄ wherein A is strontium, B is niobium, C is gallium, D is silicon, and E is oxygen. At least one electrode is connected to the piezoelectric layer and may be configured to define a device, such as a SAW resonator or filter, or a BAW resonator or filter. The ordered Langasite structure compound may have a substantially perfectly ordered structure.

Claims

1. An electronic device comprising:

a piezoelectric layer comprising an ordered Langasite structure compound having the formula A₃BC₃D₂E₁₄, wherein A is strontium, B is niobium, C is gallium, D is silicon, and E is oxygen; and

at least one electrode connected to said piezoelectric layer.

2. An electronic device according to claim 1 wherein said ordered Langasite structure compound has a substantially perfectly ordered structure.

3. An electronic device according to claim 1 wherein said at least one electrode comprises a plurality of electrodes configured so that the electronic device is a resonator.

4. An electronic device according to claim 3 wherein said plurality of electrodes are connected to a same face of said piezoelectric layer so that the electronic device is a surface acoustic wave (SAW) resonator.

5. An electronic device according to claim 4 wherein said plurality of electrodes comprises first and second interdigitated electrodes.

6. An electronic device according to claim 3 wherein said plurality of electrodes comprises first and second electrodes connected to respective opposing first and second faces of said piezoelectric layer so that the electronic device is a bulk acoustic wave (BAW) resonator.

7. An electronic device according to claim 1 wherein said at least one electrode comprises a plurality of pairs of electrodes configured so that the electronic device is a filter.

8. An electronic device according to claim 7 wherein each of said plurality of pairs of electrodes comprises first and second interdigitated electrodes.

9. An electronic device according to claim 7 wherein said plurality of pairs of electrodes are connected to a same face of said piezoelectric layer so that the electronic device is a surface acoustic wave (SAW) filter.

10. An electronic device according to claim 7 wherein said plurality of pairs of electrodes comprises first and second pairs of electrodes connected to respective opposing first and second faces of said piezoelectric layer so that the electronic device is a bulk acoustic wave (BAW) filter.

11. An electronic device according to claim 1 wherein said ordered Langasite structure compound is producible using a melt pulling crystal growth technique.

12. An electronic device according to claim 1 wherein said ordered Langasite structure compound has a relatively high thermally stability.

13. An electronic device according to claim 1 wherein components of said ordered Langasite structure compound have congruent melting properties.

15. An electronic device according to claim 14 wherein said ordered Langasite structure compound has a substantially perfectly ordered structure.

16. An electronic device according to claim 14 wherein said plurality of electrodes are connected to a same face of said piezoelectric layer so that the electronic device is a surface acoustic wave (SAW) resonator.

17. An electronic device according to claim 16 wherein said plurality of electrodes comprises first and second interdigitated electrodes.

18. An electronic device according to claim 14 wherein said plurality of electrodes comprises first and second electrodes connected to respective opposing first and second faces of said piezoelectric layer so that the electronic device is a bulk acoustic wave (BAW) resonator.

20. An electronic device according to claim 19 wherein said ordered Langasite structure compound has a substantially perfectly ordered structure.

21. An electronic device according to claim 19 wherein each of said plurality of pairs of electrodes comprises first and second interdigitated electrodes.

22. An electronic device according to claim 19 wherein said plurality of pairs of electrodes are connected to a same face of said piezoelectric layer so that the electronic device is a surface acoustic wave (SAW) filter.

23. An electronic device according to claim 19 wherein said plurality of pairs of electrodes comprises first and second pairs of electrodes connected to respective opposing first and second faces of said piezoelectric layer so that the electronic device is a bulk acoustic wave (BAW) filter.

25. A method according to claim 24 wherein the ordered Langasite structure compound has a substantially perfectly ordered structure.

26. A method according to claim 24 wherein connecting at least one electrode comprises connecting a plurality of electrodes configured so that the electronic device is a resonator.

27. A method according to claim 26 wherein connecting the plurality of electrodes comprises connecting the electrodes to a same face of the piezoelectric layer so that the electronic device is a surface acoustic wave (SAW) resonator.

28. A method according to claim 26 wherein connecting the plurality of electrodes comprises connecting first and second electrodes to respective opposing first and second faces of the piezoelectric layer so that the electronic device is a bulk acoustic wave (BAW) resonator.

29. A method according to claim 24 wherein connecting the at least one electrode comprises connecting a plurality of pairs of electrodes configured so that the electronic device is a filter.

30. A method according to claim 29 wherein connecting the plurality of pairs of electrodes comprises connecting the pairs of electrodes to a same face of the piezoelectric layer so that the electronic device is a surface acoustic wave (SAW) filter.

31. A method according to claim 29 wherein connecting the plurality of pairs of electrodes comprises connecting first and second pairs of electrodes to respective opposing first and second faces of the piezoelectric layer so that the electronic device is a bulk acoustic wave (BAW) filter.

32. A method according to claim 24 wherein providing the ordered Langasite structure compound comprises producing the ordered Langasite structure compound using a melt pulling crystal growth technique.

14. An electronic device comprising:

a piezoelectric layer comprising an ordered Langasite structure compound having the formula Sr₃NbGa₃Si₂O₁₄; and

a plurality of electrodes connected to said piezoelectric layer and configured so that the electronic device is a resonator.

19. An electronic device comprising:

a piezoelectric layer comprising an ordered Langasite structure compound having the formula Sr₃NbGa₃Si₂O₁₄; and

a plurality of pairs of electrodes connected to said piezoelectric layer and configured so that the electronic device is a filter.

24. A method for making an electronic device comprising:

providing a piezoelectric layer comprising an ordered Langasite structure compound having the formula A₃BC₃D₂E₁₄, wherein A is strontium, B is niobium, C is gallium, D is silicon, and E is oxygen; and

connecting at least one electrode to the piezoelectric layer.