Heat dissipation structure for laterally excited bulk acoustic wave device
An acoustic wave device is disclosed. The acoustic wave deice can include a membrane structure and a support substrate. The membrane structure includes a piezoelectric layer, an interdigital transducer electrode arranged on the piezoelectric layer, and a thermally conductive layer arranged at least partially in contact with the piezoelectric layer. The support substrate is connected to the membrane structure and configured such that a cavity is provided next to the membrane structure. The acoustic wave device can laterally excite a bulk acoustic wave.
1 . An acoustic wave device comprising:
a membrane structure including a piezoelectric layer, an interdigital transducer electrode arranged on the piezoelectric layer, signal lines, and a thermally conductive layer arranged at least partially in contact with the piezoelectric layer; and
a support substrate connected to the membrane structure and configured such that a cavity is provided between the support substrate and the membrane structure, the cavity being on an opposite side of the piezoelectric layer than the interdigital transducer electrode, and the thermally conductive layer covering at least a portion of the interdigital transducer electrode and covering at least a portion of the signal lines.
2 . The acoustic wave device of claim 1 wherein the interdigital transducer electrode is sandwiched between the thermally conductive layer and the piezoelectric layer.
3 . The acoustic wave device of claim 1 wherein the thermally conductive layer includes a metal or a semiconductor with high thermal conductivity.
4 . The acoustic wave device of claim 1 wherein the thermally conductive layer has a thermal conductivity of 100 W/(m*K) or more.
5 . The acoustic wave device of claim 1 wherein the thermally conductive layer includes at least one of aluminum, molybdenum, tungsten, ruthenium, aluminum silicide, aluminum nitride, silicon, diamond-like carbon, or silicon nitride.
6 . The acoustic wave device of claim 1 wherein the interdigital transducer electrode has a duty factor of 0.5 or lower.
7 . The acoustic wave device of claim 1 wherein the thermally conductive layer has a thickness in a range from 30 nanometers to 300 nanometers.
8 . The acoustic wave device of claim 1 wherein the acoustic wave device is a laterally excited bulk acoustic wave resonator.
9 . The acoustic wave device of claim 8 wherein the acoustic wave device is configured as an A1 mode laterally excited bulk acoustic wave resonator.
10 . The acoustic wave device of claim 8 wherein the piezoelectric layer includes lithium niobate.
11 . The acoustic wave device of claim 8 wherein the piezoelectric layer includes a lithium niobate crystal cut with a surface normal orientation of (α, β, γ), with a between −10° and +10°, β between −10° and +10°, and γ between 80° and 100° in Euler angles.
12 . The acoustic wave device of claim 8 wherein the piezoelectric layer includes a lithium niobate crystal cut with a surface normal orientation of (α, β, γ)=(0°, 0°, 90°) in Euler angles.
13 . A wireless communication device comprising:
the acoustic wave device of claim 1 ;
an antenna operatively coupled to the acoustic wave device;
a radio frequency amplifier operatively coupled to the acoustic wave device and configured to amplify a radio frequency signal; and
a transceiver in communication with the radio frequency amplifier.
14 . The wireless communication device of claim 13 further comprising a baseband processor in communication with the transceiver.
15 . An acoustic wave device comprising:
a membrane structure including a piezoelectric layer, an interdigital transducer electrode arranged on the piezoelectric layer, and a thermally conductive layer arranged at least partially in contact with the piezoelectric layer, the thermally conductive layer is arranged at a first side of the piezoelectric layer opposite to a second side on which the interdigital transducer electrode is arranged on the piezoelectric layer; and
a support substrate connected to the membrane structure and configured such that a cavity is provided between the support substrate and the membrane structure, the cavity being on an opposite side of the piezoelectric layer than the interdigital transducer electrode, and the thermally conductive layer extends along a surface of the support substrate facing the cavity.
16 . The acoustic wave device of claim 15 wherein the thermally conductive layer has a thermal conductivity of 100 W/(m*K) or more.
17 . The acoustic wave device of claim 15 wherein the interdigital transducer electrode has a duty factor of 0.4 or lower.
18 . A radio frequency module comprising:
an acoustic wave device including a membrane structure and a support substrate, the membrane structure including a piezoelectric layer, an interdigital transducer electrode arranged on the piezoelectric layer, and a thermally conductive layer arranged at least partially in contact with the piezoelectric layer, the support substrate being connected to the membrane structure and configured such that a cavity is provided between the support substrate and the membrane structure, the cavity being on an opposite side of the piezoelectric layer than the interdigital transducer electrode; and
a radio frequency circuit element coupled to the acoustic wave device, the acoustic wave device and the radio frequency circuit element being enclosed within a common package.
19 . The radio frequency module of claim 18 wherein the radio frequency circuit element is a radio frequency amplifier arranged to amplify a radio frequency signal.
20 . The radio frequency module of claim 18 wherein the radio frequency circuit element is a switch configured to selectively couple the acoustic wave device to an antenna port of the radio frequency module.