US 11,770,110 B2Granted

Acoustic wave device

AssigneeMurata Manufacturing Co., Ltd.

InventorsShou Nagatomo, Katsuya Daimon

Life of this patent

Estimating the term…

Abstract

An acoustic wave device includes a high-acoustic-velocity layer, a piezoelectric layer made of lithium tantalate, and an interdigital transducer electrode that are successively laminated. An acoustic velocity of a bulk wave propagating in the high-acoustic-velocity layer is higher than an acoustic velocity of an acoustic wave propagating in the piezoelectric layer, and an acoustic velocity Vsub of a fast transversal bulk wave propagating in the high-acoustic-velocity layer satisfies Vsh0≤Vsub≤Vsp with respect to an acoustic velocity Vsh0 of an SH0 mode and an acoustic velocity Vsp of a mode becoming a spurious of which acoustic velocity is not lower than the acoustic velocity of the SH0 mode, wherein the acoustic velocity Vsh0 and the acoustic velocity Vsp is obtained from Eq. (1).

Claims18

Dependent claims

An acoustic wave device comprising:

a high-acoustic-velocity layer;
a piezoelectric layer laminated on the high-acoustic-velocity layer, the piezoelectric layer being made of lithium tantalate;
and
an interdigital transducer electrode provided on the piezoelectric layer;
wherein
an acoustic velocity of a bulk wave propagating in the high-acoustic-velocity layer is higher than an acoustic velocity of an acoustic wave propagating in the piezoelectric layer;
and
an acoustic velocity Vsub of a fast transversal bulk wave propagating in the high-acoustic-velocity layer satisfies Vsh0≤Vsub≤Vsp with respect to an acoustic velocity Vsh0 of an SH0 mode and an acoustic velocity Vsp of a mode becoming a spurious response of which acoustic velocity is not lower than the acoustic velocity of the SH0 mode, the acoustic velocity Vsh0 and the acoustic velocity Vsp being obtained from Eq. (1) below;
⁢
Eq
.
⁢
(
1
)
V
mode
=
a
T
piezo
(
2
)
⁡
(
(
T
piezo
-
c
T
piezo
)
2
+
b
T
piezo
(
2
)
)
+
a
T
piezo
(
1
)
⁡
(
T
piezo
-
c
T
piezo
)
+
a
T
e
(
2
)
⁡
(
(
T
e
-
c
T
e
)
2
+
b
T
e
(
2
)
)
+
a
T
e
(
1
)
⁡
(
T
e
-
c
T
e
)
+
a
θ
(
2
)
⁡
(
(
θ
-
c
θ
)
2
+
b
θ
(
2
)
)
+
a
θ
(
1
)
⁡
(
θ
-
c
θ
)
+
a
Y
(
2
)
⁡
(
(
Y
-
c
Y
)
2
+
b
Y
(
2
)
)
+
a
γ
(
1
)
⁡
(
Y
-
c
γ
)
+
a
ρ
(
2
)
⁡
(
(
ρ
-
c
ρ
)
2
+
b
ρ
(
2
)
)
+
a
ρ
(
1
)
⁡
(
Y
-
c
ρ
)
+
d
T
piezoTe
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
T
e
-
c
T
e
)
+
d
T
piezo
⁢
θ
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
θ
-
c
θ
)
+
d
T
piezo
⁢
Y
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
Y
-
c
Y
)
+
d
T
piezo
⁢
⁢
ρ
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
Y
-
c
ρ
)
+
d
T
e
⁢
θ
⁡
(
T
e
-
c
T
e
)
⁢
(
θ
-
c
θ
)
+
d
T
e
⁢
Y
⁡
(
T
e
-
c
T
e
)
⁢
(
Y
-
c
Y
)
+
d
T
e
⁢
ρ
⁡
(
T
e
-
c
T
e
)
⁢
(
ρ
-
c
ρ
)
+
d
θ
⁢
⁢
Y
⁡
(
θ
-
c
θ
)
⁢
(
Y
-
c
Y
)
+
d
θ
⁢
⁢
ρ
⁡
(
T
θ
-
c
θ
)
⁢
(
ρ
-
c
p
)
+
d
Y
ρ
⁡
(
Y
-
c
Y
)
⁢
(
ρ
-
c
ρ
)
+
e
in Eq. (1), Vmode is Vsh0 or Vsp, coefficients for Vsh0 and Vsp are as listed in Table 1 below, λ is a wavelength determined by a pitch of electrode fingers of the interdigital transducer electrode, Tpiezo is a film thickness (λ) of the piezoelectric layer, Te is a film thickness (λ) of the interdigital transducer electrode, θ is a second Euler angle (°) of the piezoelectric layer, Y is the Young's modulus (GPa) of the interdigital transducer electrode, and ρ is the density (g/cm3) of the interdigital transducer electrode:
TABLE 1
MODE ACOUSTIC
VELOCITY
V_SH0
V_SP
aTpiezo(2)
7.048E+00
4.060E+01
aTpiezo(1)
−1.560E+00
−3.466E+00
bTpiezo(2)
−1.250E−02
−1.250E−02
cTpiezo
3.500E−01
3.500E−01
aTe(2)
5.482E+01
7.950E+01
aTe(1)
−7.154E+00
−7.636E+00
bTe(2)
−3.200E−03
−3.200E−03
cTe
1.200E−01
1.200E−01
a θ (2)
0.000E+00
0.000E+00
a θ (1)
8.215E−03
1.271E−02
b θ (2)
0.000E+00
0.000E+00
c θ
1.395E+02
1.395E+02
aY(2)
0.000E+00
3.371E−06
aY(1)
1.347E−04
−6.086E−04
bY(2)
0.000E+00
−3.954E+04
cY
3.515E+02
3.515E+02
a ρ (2)
3.156E−03
3.849E−03
a ρ (1)
−7.670E−02
−8.435E−02
b ρ (2)
−5.832E+01
−5.832E+01
c ρ
1.350E+01
1.350E+01
dTpiezoTe
0.000E+00
0.000E+00
dTpiezo θ
0.000E+00
0.000E+00
dTpiezoY
0.000E+00
0.000E+00
dTpiezo ρ
9.988E−02
9.090E−02
dTe θ
0.000E+00
0.000E+00
dTeY
−7.413E−03
−1.586E−02
dTe ρ
0.000E+00
0.000E+00
d θ Y
0.000E+00
0.000E+00
d θ ρ
0.000E+00
0.000E+00
dY ρ
−4.456E−05
−9.875E−05
e
3.248E+00
4.270E+00.

518 more elements

An acoustic wave device comprising:

a high-acoustic-velocity layer;
an intermediate layer laminated on the high-acoustic-velocity layer, the intermediate layer being made of silicon oxide;
a piezoelectric layer laminated on the intermediate layer and being made of lithium tantalate;
and
an interdigital transducer electrode provided on the piezoelectric layer;
wherein
an acoustic velocity of a bulk wave propagating in the high-acoustic-velocity layer is higher than an acoustic velocity of an acoustic wave propagating in the piezoelectric layer;
and
an acoustic velocity Vsub of a fast transversal bulk wave propagating in the high-acoustic-velocity layer satisfies Vsh0≤Vsub≤Vsp with respect to an acoustic velocity Vsh0 of an SH0 mode and an acoustic velocity Vsp of a mode becoming a spurious of which acoustic velocity is not lower than the acoustic velocity of the SH0 mode, the acoustic velocity Vsh0 and the acoustic velocity Vsp being obtained from Eq. (2) below;
⁢
Eq
.
⁢
(
2
)
V
mode
=
a
T
piezo
(
2
)
⁡
(
(
T
piezo
-
c
T
piezo
)
2
+
b
T
piezo
(
2
)
)
+
a
T
piezo
(
1
)
⁡
(
T
piezo
-
c
T
piezo
)
+
a
T
int
(
2
)
⁡
(
(
T
int
-
c
T
int
)
2
+
b
T
int
(
2
)
)
+
a
T
int
(
1
)
⁡
(
T
int
-
c
T
int
)
+
a
T
e
(
2
)
⁡
(
(
T
e
-
c
T
e
)
2
+
b
T
e
(
2
)
)
+
a
T
e
(
1
)
⁡
(
T
e
-
c
T
e
)
+
a
θ
(
2
)
⁡
(
(
θ
-
c
θ
)
2
+
b
θ
(
2
)
)
+
a
θ
(
1
)
⁡
(
θ
-
c
θ
)
+
a
Y
(
2
)
⁡
(
(
Y
-
c
Y
)
2
+
b
Y
(
2
)
)
+
a
Y
(
1
)
⁡
(
Y
-
c
Y
)
+
a
ρ
(
2
)
⁡
(
(
ρ
-
c
ρ
)
2
+
b
ρ
(
2
)
)
+
a
ρ
(
1
)
⁡
(
Y
-
c
ρ
)
+
d
T
piezo
⁢
T
int
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
T
int
-
c
int
)
+
d
T
piezo
⁢
⁢
Te
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
T
e
-
c
T
e
)
+
d
T
piezo
⁢
θ
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
θ
-
c
θ
)
+
d
T
piezo
⁢
Y
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
Y
-
c
Y
)
+
d
T
piezo
⁢
ρ
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
Y
-
c
ρ
)
+
d
T
int
⁢
T
e
⁡
(
T
int
-
c
T
int
)
⁢
(
T
e
-
c
T
e
)
+
d
T
int
⁢
θ
⁡
(
T
int
-
c
T
e
)
⁢
(
θ
-
c
θ
)
+
d
T
int
⁢
Y
⁡
(
T
int
-
c
T
int
)
⁢
(
Y
-
c
Y
)
+
d
T
int
⁢
ρ
⁡
(
T
int
-
c
T
int
)
⁢
(
ρ
-
c
ρ
)
+
d
T
e
⁢
θ
⁡
(
T
e
-
c
T
e
)
⁢
(
θ
-
c
θ
)
+
d
T
e
⁢
Y
⁡
(
T
e
-
c
T
e
)
⁢
(
Y
-
c
Y
)
+
d
T
e
⁢
ρ
⁡
(
T
e
-
c
T
e
)
⁢
(
ρ
-
c
ρ
)
+
d
θ
⁢
⁢
Y
⁡
(
θ
-
c
θ
)
⁢
(
Y
-
c
Y
)
+
d
θ
⁢
⁢
ρ
⁡
(
T
θ
-
c
θ
)
⁢
(
ρ
-
c
ρ
)
+
d
Y
⁢
⁢
ρ
⁡
(
Y
-
c
Y
)
⁢
(
ρ
-
c
ρ
)
+
e
in Eq. (2), Vmode is Vsh0 or Vsp, coefficients for Vsh0 and Vsp are as listed in Table 2 below, λ is a wavelength determined by a pitch of electrode fingers of the interdigital transducer electrode, Tpiezo is a film thickness (λ) of the piezoelectric layer, Te is a film thickness (λ) of the interdigital transducer electrode, θ is a second Euler angle (°) of the piezoelectric layer, Y is the Young's modulus (GPa) of the interdigital transducer electrode, and ρ is the density (g/cm3) of the interdigital transducer electrode:
TABLE 2
MODE ACOUSTIC
VELOCITY
V_SH0
V_SP
aTpiezo(2)
0.000E+00
−1.163E+01
aTpiezo(1)
8.939E−01
−1.176E+00
bTpiezo(2)
0.000E+00
1.250E−02
cTpiezo
2.500E−01
2.500E−01
aTint(2)
0.000E+00
−2.248E+01
aTint(1)
−5.610E−01
1.908E+00
bTint(2)
0.000E+00
1.250E−02
cTint
2.500E−01
2.500E−01
aTe(2)
4.789E+01
0.000E+00
aTe(1)
−6.682E+00
−6.371E+00
bTe(2)
2.000E−03
0.000E+00
cTe
1.000E−01
1.000E−01
a θ (2)
−2.255E−04
0.000E+00
a θ (1)
2.552E−04
0.000E+00
b θ (2)
1.667E+02
0.000E+00
c θ
1.400E+02
1.400E+02
aY(2)
0.000E+00
0.000E+00
aY(1)
−2.030E−05
6.691E−04
bY(2)
0.000E+00
0.000E+00
cY
4.218E+02
4.218E+02
a ρ (2)
2.215E−03
0.000E+00
a ρ (1)
−5.835E−02
−4.208E−02
b ρ (2)
5.832E+01
0.000E+00
c ρ
1.350E+01
1.350E+01
dTpiezoTin
2.593E+00
−2.616E+01
dTpiezoTe
1.069E+01
0.000E+00
dTpiezo θ
0.000E+00
0.000E+00
dTpiezoY
−2.009E−03
−2.664E−03
dTpiezo ρ
7.747E−02
0.000E+00
dTintTe
0.000E+00
2.905E+01
dTint θ
0.000E+00
−4.267E−02
dTintY
5.308E−04
0.000E+00
dTint ρ
0.000E+00
1.901E−01
dTe θ
0.000E+00
1.520E−01
dTeY
−5.003E−03
7.229E−03
dTe ρ
−1.701E−01
−5.170E−01
d θ Y
0.000E+00
0.000E+00
d θ ρ
0.000E+00
9.593E−04
dY ρ
−3.071E−05
0.000E+00
e
3.120E+00
5.104E+00.

707 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/823,439Filed 19 Mar 2020
Priority: JP 2019-05406722 Mar 2019
Published: US 2020/0304094 A124 Sep 2020
Granted: 26 Sep 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

H03H 9/02015
Of bulk acoustic wave devices: characteristics of piezoelectric layers, e.g. cutting angles
H03H 9/02559
Characteristics of substrate, e.g. cutting angles: of lithium niobate or lithium-tantalate substrates
H03H 9/02062
Of bulk acoustic wave devices: details relating to the vibration mode
H03H 9/02086
Of bulk acoustic wave devices: means for compensation or elimination of undesirable effects

Family

US 2020/0304094 A1Pre-grant publication · published 24 Sep 2020
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Abstract

An acoustic wave device comprising:

a high-acoustic-velocity layer;
a piezoelectric layer laminated on the high-acoustic-velocity layer, the piezoelectric layer being made of lithium tantalate;
and
an interdigital transducer electrode provided on the piezoelectric layer;
wherein
an acoustic velocity of a bulk wave propagating in the high-acoustic-velocity layer is higher than an acoustic velocity of an acoustic wave propagating in the piezoelectric layer;
and
an acoustic velocity Vsub of a fast transversal bulk wave propagating in the high-acoustic-velocity layer satisfies Vsh0≤Vsub≤Vsp with respect to an acoustic velocity Vsh0 of an SH0 mode and an acoustic velocity Vsp of a mode becoming a spurious response of which acoustic velocity is not lower than the acoustic velocity of the SH0 mode, the acoustic velocity Vsh0 and the acoustic velocity Vsp being obtained from Eq. (1) below;
⁢
Eq
.
⁢
(
1
)
V
mode
=
a
T
piezo
(
2
)
⁡
(
(
T
piezo
-
c
T
piezo
)
2
+
b
T
piezo
(
2
)
)
+
a
T
piezo
(
1
)
⁡
(
T
piezo
-
c
T
piezo
)
+
a
T
e
(
2
)
⁡
(
(
T
e
-
c
T
e
)
2
+
b
T
e
(
2
)
)
+
a
T
e
(
1
)
⁡
(
T
e
-
c
T
e
)
+
a
θ
(
2
)
⁡
(
(
θ
-
c
θ
)
2
+
b
θ
(
2
)
)
+
a
θ
(
1
)
⁡
(
θ
-
c
θ
)
+
a
Y
(
2
)
⁡
(
(
Y
-
c
Y
)
2
+
b
Y
(
2
)
)
+
a
γ
(
1
)
⁡
(
Y
-
c
γ
)
+
a
ρ
(
2
)
⁡
(
(
ρ
-
c
ρ
)
2
+
b
ρ
(
2
)
)
+
a
ρ
(
1
)
⁡
(
Y
-
c
ρ
)
+
d
T
piezoTe
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
T
e
-
c
T
e
)
+
d
T
piezo
⁢
θ
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
θ
-
c
θ
)
+
d
T
piezo
⁢
Y
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
Y
-
c
Y
)
+
d
T
piezo
⁢
⁢
ρ
⁡
(
T
piezo
-
c
T
piezo
)
⁢
(
Y
-
c
ρ
)
+
d
T
e
⁢
θ
⁡
(
T
e
-
c
T
e
)
⁢
(
θ
-
c
θ
)
+
d
T
e
⁢
Y
⁡
(
T
e
-
c
T
e
)
⁢
(
Y
-
c
Y
)
+
d
T
e
⁢
ρ
⁡
(
T
e
-
c
T
e
)
⁢
(
ρ
-
c
ρ
)
+
d
θ
⁢
⁢
Y
⁡
(
θ
-
c
θ
)
⁢
(
Y
-
c
Y
)
+
d
θ
⁢
⁢
ρ
⁡
(
T
θ
-
c
θ
)
⁢
(
ρ
-
c
p
)
+
d
Y
ρ
⁡
(
Y
-
c
Y
)
⁢
(
ρ
-
c
ρ
)
+
e
in Eq. (1), Vmode is Vsh0 or Vsp, coefficients for Vsh0 and Vsp are as listed in Table 1 below, λ is a wavelength determined by a pitch of electrode fingers of the interdigital transducer electrode, Tpiezo is a film thickness (λ) of the piezoelectric layer, Te is a film thickness (λ) of the interdigital transducer electrode, θ is a second Euler angle (°) of the piezoelectric layer, Y is the Young's modulus (GPa) of the interdigital transducer electrode, and ρ is the density (g/cm3) of the interdigital transducer electrode:
TABLE 1
MODE ACOUSTIC
VELOCITY
V_SH0
V_SP
aTpiezo(2)
7.048E+00
4.060E+01
aTpiezo(1)
−1.560E+00
−3.466E+00
bTpiezo(2)
−1.250E−02
−1.250E−02
cTpiezo
3.500E−01
3.500E−01
aTe(2)
5.482E+01
7.950E+01
aTe(1)
−7.154E+00
−7.636E+00
bTe(2)
−3.200E−03
−3.200E−03
cTe
1.200E−01
1.200E−01
a θ (2)
0.000E+00
0.000E+00
a θ (1)
8.215E−03
1.271E−02
b θ (2)
0.000E+00
0.000E+00
c θ
1.395E+02
1.395E+02
aY(2)
0.000E+00
3.371E−06
aY(1)
1.347E−04
−6.086E−04
bY(2)
0.000E+00
−3.954E+04
cY
3.515E+02
3.515E+02
a ρ (2)
3.156E−03
3.849E−03
a ρ (1)
−7.670E−02
−8.435E−02
b ρ (2)
−5.832E+01
−5.832E+01
c ρ
1.350E+01
1.350E+01
dTpiezoTe
0.000E+00
0.000E+00
dTpiezo θ
0.000E+00
0.000E+00
dTpiezoY
0.000E+00
0.000E+00
dTpiezo ρ
9.988E−02
9.090E−02
dTe θ
0.000E+00
0.000E+00
dTeY
−7.413E−03
−1.586E−02
dTe ρ
0.000E+00
0.000E+00
d θ Y
0.000E+00
0.000E+00
d θ ρ
0.000E+00
0.000E+00
dY ρ
−4.456E−05
−9.875E−05
e
3.248E+00
4.270E+00.

518 more elements

Facts

Application

16/823,439Filed 19 Mar 2020

Priority

JP 2019-05406722 Mar 2019

Published

US 2020/0304094 A124 Sep 2020

Granted

26 Sep 2023

Term ends

Not estimatedThe source records don’t support an estimate.

Classification11 codes

H03H 9/02015
Of bulk acoustic wave devices: characteristics of piezoelectric layers, e.g. cutting angles
H03H 9/02559
Characteristics of substrate, e.g. cutting angles: of lithium niobate or lithium-tantalate substrates
H03H 9/02062
Of bulk acoustic wave devices: details relating to the vibration mode
H03H 9/02086
Of bulk acoustic wave devices: means for compensation or elimination of undesirable effects