Micromechanical piezoelectric device
View Patent ↗A micromechanical device includes a single crystal micromachined micromechanical structure. At least a portion of the micromechanical structure is capable of performing a mechanical motion. A piezoelectric epitaxial layer covers at least a part of said portion of the micromechanical structure that is capable of performing a mechanical motion. The micromechanical structure and piezoelectric epitaxial layer are composed of different materials. At least one electrically conducting layer is formed to cover at least part of the piezoelectric epitaxial layer.
1. A micromechanical device comprising:
a single crystal micromachined micromechanical structure, at least a portion of the micromechanical structure capable of performing a mechanical motion; and
a piezoelectric epitaxial layer covering at least a part of said portion of the micromechanical structure that is capable of performing a mechanical motion, the micromechanical structure and piezoelectric epitaxial layer being composed of different materials; and
at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer.
2. The device of claim 1 in which the micromechanical structure is formed from an electrically conductive semiconductor substrate.
3. The device of claim 2 further comprising at least one electrical contact formed to the micromechanical structure, said electrical contact being electrically connected to the portion of the micromechanical structure capable of performing a mechanical motion.
4. The device of claim 3 further comprising an electrical source connected between at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer and at least one electrical contact formed to the micromechanical structure.
5. The device of claim 3 further comprising a measuring device connected between at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer and at least one electrical contact formed to the micromechanical structure.
6. The device of claim 10 further comprising a substance sensitive layer over at least a portion of the micromechanical structure that is capable of performing a mechanical motion.
7. The device of claim 1 in which the at least one electrically conductive layer is an interdigital electrode.
8. The device of claim 1 in which the portion of the micromechanical structure capable of performing a mechanical motion is one of a microcantilever, microbridge, membrane, perforated membrane, tethered proof mass and tethered plate.
9. A micromechanical device comprising:
a single crystal micromachined micromechanical structure formed from a material selected from the group consisting of SiC and Si, at least a portion of the micromechanical structure capable of performing a mechanical motion; and
a piezoelectric epitaxial layer covering at least a part of said portion of the micromechanical structure that is capable of performing a mechanical motion, the piezoelectric epitaxial layer being formed of AlGaInN solid solution; and
at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer.
10. The device of claim 9 in which the piezoelectric epitaxial layer is formed of AlN.
11. The device of claim 9 in which the micromechanical structure is formed from one of 6H—SiC and 4H—SiC.
12. The device of claim 9 in which the micromechanical structure is formed of (111) Si.
13. The device of claim 9 in which the micromechanical structure is electrically conductive.
14. The device of claim 13 further comprising at least one electrical contact formed to the micromechanical structure, said electrical contact being electrically connected to the portion of the micromechanical structure capable of performing a mechanical motion.
15. The device of claim 14 further comprising an electrical source connected between at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer and at least one electrical contact formed to the micromechanical structure.
16. The device of claim 14 further comprising a measuring device connected between at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer and at least one electrical contact formed to the micromechanical structure.
17. The device of claim 9 further comprising a substance sensitive layer over at least a portion of the micromechanical structure that is capable of performing a mechanical motion.
18. The device of claim 9 in which the at least one electrically conductive layer is an interdigital electrode.
19. The device of claim 9 in which the portion of the micromechanical structure capable of performing a mechanical motion is one of a microcantilever, microbridge, membrane, perforated membrane, tethered proof mass and tethered plate.
20. A micromechanical device comprising:
a single crystal micromachined micromechanical structure formed from a material selected from the group consisting of 6H—SiC, 4H—SiC and (111) Si, at least a portion of the micromechanical structure capable of performing a mechanical motion; and
a piezoelectric epitaxial layer covering at least a part of said portion of the micromechanical structure that is capable of performing a mechanical motion, the piezoelectric epitaxial layer being formed of AlGaInN solid solution; and
at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer.
21. The device of claim 20 in which the piezoelectric epitaxial layer is formed of AlN.
22. The device of claim 20 in which the micromechanical structure is formed from a substrate having a p-type region over a first n-type region, the portion of the micromechanical structure capable of performing a mechanical motion being composed of a portion of the p-type region suspended over a cavity in the n-type region.
23. The device of claim 22 further comprising at least one electrical contact formed to the p-type region of the micromechanical structure, said electrical contact electrically connected via the p-type region to the portion of the micromechanical structure capable of performing a mechanical motion.
24. The device of claim 23 further comprising an electrical source connected between at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer and at least one electrical contact formed to the micromechanical structure.
25. The device of claim 23 further comprising a measuring device connected between at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer and at least one electrical contact formed to the micromechanical structure.
26. The device of claim 20 further comprising a substance sensitive layer over at least a portion of the micromechanical structure that is capable of performing a mechanical motion.
27. The method of claim 22 further comprising forming the micromechanical structure from a substrate further including a second n-type region over at least a portion of the p-type region, such that at least a portion of the micromechanical structure capable of performing a mechanical motion being composed of said second n-type region covering a p-type region.
28. The device of claim 27 further at least one electrical contact formed to the second n-type region of the micromechanical structure, said electrical contact electrically connected via the second n-type region to the portion of the micromechanical structure capable of performing a mechanical motion.
29. The device of claim 28 further comprising an electrical source connected between at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer and at least one electrical contact formed to the micromechanical structure.
30. The device of claim 28 further comprising a measuring device connected between at least one electrically conductive layer covering at least part of the piezoelectric epitaxial layer and at least one electrical contact formed to the micromechanical structure.
31. The device of claim 27 further comprising a substance sensitive layer over at least a portion of the micromechanical structure that is capable of performing a mechanical motion.
32. The device of claim 20 in which the at least one electrically conductive layer is an interdigital electrode.
33. The device of claim 20 in which the portion of the micromechanical structure capable of performing a mechanical motion is one of a microcantilever, microbridge, membrane, perforated membrane, tethered proof mass and tethered plate.