Acoustic transducer with gap-controlling geometry and method of manufacturing an acoustic transducer
A transducer of the preferred embodiment including a transducer and a plurality of adjacent, tapered cantilevered beams. Each of the beams define a beam base, a beam tip, and a beam body disposed between the beam base and the beam tip. The beams are arranged such that each of the beam tips extends toward a common area. Each beam is joined to the substrate along the beam base and is free from the substrate along the beam body. A preferred method of manufacturing a transducer can include: depositing alternating layers of piezoelectric and electrode onto the substrate in block, processing the deposited layers to define cantilever geometry in block, depositing metal traces in block, and releasing the cantilevered beams from the substrate in block.
1. A transducer, comprising:
a substrate having a region; and
a plurality of cantilevered beams, each cantilevered beam of the plurality of cantilevered beams comprising:
at least one piezoelectric layer interspersed between electrode layers, wherein the electrode layers cover two-thirds or less of each cantilevered beam of the plurality of cantilevered beams; and
a tapered beam body that extends from a beam base portion to a beam tip portion over the region, with beam base portions supported over portions of the substrate, and with beam tip portions extending towards a common area.
2. The transducer of claim 1 , wherein the region comprises a void region in the substrate.
3. The transducer of claim 1 , wherein the at least one piezoelectric layer comprises one or more of aluminum nitride (AlN), lead zirconate titanate (PZT), zinc oxide (ZnO), polyvinylidene fluoride (PVDF), or lead magnesium magnesium niobate-lead titanate (PMN-PT).
4. The transducer of claim 1 , wherein at least one cantilevered beam of the plurality of cantilevered beams comprises a first electrode layer of the electrode layers on a first surface of the at least one piezoelectric layer.
5. The transducer of claim 4 , wherein the at least one cantilevered beam of the plurality of cantilevered beams comprises a second electrode layer of the electrode layers on a second surface of the at least one piezoelectric layer.
6. The transducer of claim 5 , wherein at least one of the first electrode layer or the second electrode layer comprises one or more of molybdenum (Mo), titanium (Ti), aluminum (Al), or platinum (Pt).
7. The transducer of claim 1 , wherein each cantilevered beam of the plurality of cantilevered beams is joined to the substrate along at least a portion of the beam base portion.
8. The transducer of claim 1 , wherein each cantilevered beam of the plurality of cantilevered beams is joined to the substrate adjacent to the region and along the beam base portion through a portion of the at least one piezoelectric layer.
9. The transducer of claim 1 , wherein each cantilevered beam of the plurality of cantilevered beams is joined to the substrate adjacent to the region and along the beam base portion through a portion of an electrode layer.
10. The transducer of claim 1 , wherein each cantilevered beam of the plurality of cantilevered beams is free from the substrate along the tapered beam body and the beam tip portion.
11. The transducer of claim 1 , wherein a gap between adjacent cantilevered beams is substantially uniform.
12. The transducer of claim 11 , wherein the gap is less than or equal to 1 micron.
13. The transducer of claim 1 , wherein each cantilevered beam of the plurality of cantilevered beams comprises a triangular shape.
14. The transducer of claim 1 , wherein the beam base portions form a substantially polygonal perimeter about the region of the substrate.
15. The transducer of claim 1 , wherein the transducer comprises a microphone.