CN104917487B - Resonance filter - Google Patents
Resonance filter Download PDFInfo
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- CN104917487B CN104917487B CN201410084689.0A CN201410084689A CN104917487B CN 104917487 B CN104917487 B CN 104917487B CN 201410084689 A CN201410084689 A CN 201410084689A CN 104917487 B CN104917487 B CN 104917487B
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- low impedance
- multilayer film
- resonance filter
- coupled structure
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Abstract
The present invention discloses a kind of resonance filter, and top electrode that the multilayer film coupled structure that is set on the lower electrode it includes the lower electrode for having a substrate, one to be set in the substrate, one, one are set in the multilayer film coupled structure, first piezoelectric layer being located between the lower electrode and the multilayer film coupled structure and one are located in the second piezoelectric layer between the multilayer film coupled structure and the top electrode.The multilayer film coupled structure includes an at least insulating materials.
Description
Technical field
The present invention relates to a kind of resonance filters, more particularly to one kind is to stack crystal filter (stacked crystal
Filter, hereinafter referred to as SCF) resonance filter made of modal creation.
Background technique
In recent years, when making high frequency communications filter (filter) or duplexer (duplexer), piezoelectricity is mostly used greatly
Film producing process (piezoelectric thin film process) makes ultrasonic element.And piezoelectric membrane sound wave
Element according to structure can probably be divided into diaphragm type bulk acoustic wave resonator (thin film bulk acoustic resonator,
FBAR) and distributed bragg reflector support resonator (solidly mounted resonator, SMR).
Diaphragm type bulk acoustic wave resonator made of the existing modal creation with SCF includes a top electrode, a target and one
Lower electrode, and one piezoelectric layer of sandwiched is distinguished between top electrode, target and lower electrode.For example, when top electrode is as one
When input electrode, target is as a grounding electrode and lower electrode is used as an output electrode.When signal via input terminal into
After entering input electrode, the piezoelectric layer between input electrode and grounding electrode can generate bulk acoustic wave (bulk acoustic wave) simultaneously
The piezoelectric layer being transferred between grounding electrode and output electrode.That is, can be generated between input electrode and input electrode altogether
Vibration phenomenon, therefore signal can be transferred to output end via output electrode.
For radio-frequency filter (radio frequency, RFfilter), insertion loss (insertion loss) with
Bandwidth (bandwidth) is the key factor of two decision filters performance, therefore how to reduce insertion loss while improving
Bandwidth is always the target that dealer endeavours to reach.
Summary of the invention
Therefore, a purpose of the present invention is that providing a kind of resonance filter, insertion loss can be reduced, and improve bandwidth.
The present invention provides a kind of resonance filter, which includes a substrate, one is set in the substrate
Lower electrode, one be set to multilayer film coupled structure (multi-layered coupling structure) on the lower electrode,
One be set in the multilayer film coupled structure top electrode, one be located between the lower electrode and the multilayer film coupled structure
One piezoelectric layer and one it is located in the second piezoelectric layer between the multilayer film coupled structure and the top electrode.It is worth noting that,
The multilayer film coupled structure includes an at least insulating materials.
Provided resonance filter according to the present invention is replaced existing using the multilayer film coupled structure comprising insulating materials
Middle ground electrode in SCF structure.Sound wave is confined in delivery areas by this multilayer film coupled structure, therefore can effectively gradually
Few insertion loss and transmitting lose (transmission loss) and improve bandwidth.
Detailed description of the invention
Fig. 1 is the schematic diagram of a first preferred embodiment of a resonance filter provided by the present invention.
Fig. 2 is the schematic diagram of one second preferred embodiment of a resonance filter provided by the present invention.
Main element symbol description
10 resonance filters
100 substrates
110 reflectors
120 lower electrodes
130 first piezoelectric layers
140 multilayer film coupled structures
The first low impedance layers of 142a
The second low impedance layers of 142b
142c third low impedance layers
The first high impedance layer of 144a
The second high impedance layer of 144b
146 first recessed portions
148 second recessed portions
150 second piezoelectric layers
152 first grooves
154 second grooves
160 top electrodes
170 ground termination points
The input endpoint IN
OUT exit point
The thickness of d1 the first low impedance layers and the second low impedance layers
The thickness of d2 third low impedance layers
The thickness of d3 the first high impedance layer and the second high impedance layer
Specific embodiment
Referring to Fig. 1, Fig. 1 is the schematic diagram of a first preferred embodiment of a resonance filter provided by the present invention.
As shown in Figure 1, resonance filter 10 provided by this preferred embodiment includes a substrate 100.Resonance filter 10 also includes
The multilayer film coupled structure 140 and one that the one lower electrode 120, one being set in substrate 100 is set on lower electrode 120 is set
The top electrode 160 being placed in multilayer film coupled structure 140.In other words, multilayer film coupled structure 140 is to be set to lower electrode
Between 120 and top electrode 160.Importantly, being folded with one first between lower electrode 120 and multilayer film coupled structure 140
Piezoelectric layer 130；And between multilayer film coupled structure 140 and top electrode 160, it is folded with one second piezoelectric layer 150.In other words
It says, the multilayer film coupled structure 140 of this preferred embodiment is to be set to the centre of the first piezoelectric layer 130 and the second piezoelectric layer 150.
In the preferred embodiment, top electrode 160 also includes an an input endpoint IN and exit point OUT.As shown in Figure 1, input terminal
Point IN and exit point OUT one from another entity with it is electrically isolated.In addition to this, it between lower electrode 120 and substrate 100, can also set
It is equipped with a reflector 110.Reflector 110 may include aluminium nitride (aluminum nitride, AlN), aluminium oxide
(aluminumoxide, Al2O3), tungsten (tungsten, W) or silica (silicon oxide, SiO2), but not limited to this.
Substrate 100 can be a silicon base or a GaAs (galliumarsenide, GaAs), but not limited to this.Under
Electrode 120 and top electrode 160 include any suitable conductive material, and the first piezoelectric layer 130 then includes with the second piezoelectric layer 150
Zinc oxide (zincoxide, ZnO), aluminium nitride (aluminum nitride, AlN), zinc sulphide (zincsulfide, ZnS) or
Any piezoelectric material for being fabricated to film.For example, ferroelectric ceramics (ferroelectric ceramic) material such as metatitanic acid
Lead (PbTiO3), lead zirconate titanate (Pb (ZrxTi1-x) O3) etc. materials all may be used to form the first piezoelectric layer 130 and the second piezoelectric layer
150, but not limited to this.
Please continue to refer to Fig. 1.In the second piezoelectric layer 150, it is provided with one first groove 152 and one second groove 154, and
Top electrode 160 (including input endpoint IN and exit point OUT) is then set between the first groove 152 and the second groove 154.The
One groove 152 is separated from each other with the second groove 154 by the second piezoelectric layer 150, and the second piezoelectric layer 150 is as shown in Figure 1, respectively
It is exposed to the bottom of the first groove 152 and the second groove 154.Importantly, resonance filtering provided by this preferred embodiment
Device 10 includes also a ground termination points 170, is respectively formed in the first groove 152 and the second groove 154.In addition noticeable
It is that this preferred embodiment can define the size of reflector 110 by the distance between the first groove 152 and the second groove 154.
Please referring still to Fig. 1.The multilayer film coupled structure 140 being arranged among first piezoelectric layer 130 and the second piezoelectric layer 150
Include an at least insulating materials.In the preferred embodiment, multilayer film coupled structure 140 from bottom to top also includes at least one first
Low impedance layers 142a, one second low impedance layers 142b and a third low impedance layers 142c.In the first low impedance layers 142a and second
Between low impedance layers 142b, it is folded with one first high impedance layer 144a；And in the second low impedance layers 142b and third low impedance layers
Between 142c, then one second high impedance layer 144b is folded with.First low impedance layers 142a, the second low impedance layers 142b and third are low
Impedance layer 142c includes the insulating materials one of at least within.In the preferred embodiment, the first low impedance layers 142a, second
Low impedance layers 142b and third low impedance layers 142c all includes the insulating materials.For example, the first low impedance layers 142c, second
Low impedance layers 142b and third low impedance layers 142c may include silica, but not limited to this.First high impedance layer 144a and second
High impedance layer 144b then may include amorphous silicon (amorphous silicon), platinum (Pt), molybdenum (Mo) or tantalum oxide (Ta2O5), but
It is also not necessarily limited to this.
In addition, the first low impedance layers 142a has an identical thickness d 1, third Low ESR with the second low impedance layers 142b
Layer 142c has a thickness d 2 and the first high impedance layer 144a and the second high impedance layer 144b then have a thickness d 3.It is worth note
The thickness d 1 of meaning, the first low impedance layers 142a and the second low impedance layers 142b are about the thickness d 2 of third low impedance layers 142c
Half.For example, when the first low impedance layers 142a, the second low impedance layers 142b and third low impedance layers 142c include refraction
The silica (SiOx) that coefficient is 1.45, and the first high impedance layer 144a and the second high impedance layer 144b is comprising refraction coefficient
When 3.7 amorphous silicon, about 1 micron of the thickness d 1 of the first low impedance layers 142a and the second low impedance layers 142b (micrometer,
μm), the thickness d 2 of third low impedance layers 142c is about 2 μm, the thickness of the first high impedance layer 144a and the second high impedance layer 144b
D3 then can be 0.12 μm, but not limited to this.
Please referring still to Fig. 1.Resonance filter 10 provided by this preferred embodiment also includes one first recessed portion 146,
It is formed in the insulating materials of multilayer film coupled structure 140, and is formed at the first low impedance layers 142a or the second low impedance layers
Within 142b.It as shown in Figure 1, the first recessed portion 146 preferably forms within the second low impedance layers 142b, and is the second high resistant
Anti- layer 144b is filled up.In addition, the first recessed portion 146 is preferably correspond to one of the first groove 152 or the second groove 154,
As shown in Figure 1.Due to the setting of the first recessed portion 146, multilayer film coupled structure 140 obtains an asymmetric structure kenel.
Resonance filter 10 according to provided by this preferred embodiment, the first piezoelectric layer 130 and the second piezoelectric layer 150 it
Between setting one include insulating materials multilayer film coupled structure 140, and multilayer film coupled structure 140 includes at least one low-resistance
The conductive material of anti-insulating materials and a kind of high impedance.Sound wave can be effectively confined to by this multilayer film coupled structure 140
In delivery areas.The first groove 152 and the second groove 154 being arranged in the second piezoelectric layer 150 can reduce the transmitting damage of signal
It loses and is distorted (distortion)；And it is set in the second low impedance layers 142b of multilayer film coupled structure 140, and correspond to
First recessed portion 146 of the first groove 152 or the second groove 154 makes multilayer film coupled structure 140 have an asymmetric kenel,
And this asymmetric kenel can increase the coupling of resonance filter 10, therefore resonance filter 10 can provided by this preferred embodiment
Higher bandwidth application is provided.
Next referring to Fig. 2, Fig. 2 is showing for one second preferred embodiment of a resonance filter provided by the present invention
It is intended to.First it is noted that constituent element identical with first preferred embodiment is by identical in this second preferred embodiment
Symbol description, and the selection of its material can be same as first preferred embodiment, therefore repeat no more in this.In addition, second is preferably implemented
In example, constituent element identical with first preferred embodiment can relativeness having the same, therefore all repeated no more in this.Second
Preferred embodiment and first preferred embodiment the difference is that, in the preferred embodiment, resonance filter 10 includes one the
One recessed portion 146 and one second recessed portion 148, are formed in the insulating materials of multilayer film coupled structure 140.First recessed portion
146 correspond to the first groove 152, and the second recessed portion 148 then corresponds to the second groove 154.Although it is worth noting that, first
Recessed portion 146 and the second recessed portion 148 are all formed in the insulating materials of multilayer film coupled structure 140, but the first recessed portion
146 and second recessed portion 148 be respectively arranged in the first low impedance layers 142a in the second low impedance layers 142b.As shown in Fig. 2,
In this preferred embodiment, the first recessed portion 146 is formed in the second low impedance layers 142b, and is filled out by the second high impedance layer 144b
It is full；And the second recessed portion 148 is then formed in the first low impedance layers 142a, and is filled up by the first high impedance layer 144a.In other words,
First recessed portion 146 and the second recessed portion 148 are formed asymmetrically in multilayer film coupled structure 140.Due to the first recessed portion
146 are set in different film layers from the second recessed portion 148, and multilayer film coupled structure 140 still has an asymmetric structure
Kenel.
In addition, in the change type of this preferred embodiment, the first recessed portion 146 and the second recessed portion 148 may be disposed at more
In tunic coupled structure 140 in identical film layer, but there is different depth, therefore multilayer film coupled structure 140 still has
One asymmetric structure kenel.It may include three or more recessed portions in another change type of this preferred embodiment, this etc. is recessed
Concave portion is formed asymmetrically in identical or different film layer in multilayer film coupled structure 140, so that multilayer film coupled structure 140
Still have based on an asymmetric structure kenel.
Resonance filter 10 according to provided by this preferred embodiment, in the first piezoelectric layer 130 and the second piezoelectric layer 150 it
Between setting one include insulating materials multilayer film coupled structure 140, and multilayer film coupled structure 140 includes at least one low-resistance
The conductive material of anti-insulating materials and a kind of high impedance.Sound wave can be effectively confined to by this multilayer film coupled structure 140
In delivery areas.First groove 152 and the second groove 154 are set in the second piezoelectric layer 150, the transmitting loss of signal can be reduced
And distortion.And be respectively arranged in the first low impedance layers 142a and the second low impedance layers 142b of multilayer film coupled structure 140,
And correspond respectively to the first recessed portion 146 of the first groove 152 or the second groove 154 and the second recessed portion 148 makes multilayer film
Coupled structure 140 has an asymmetric kenel, and this asymmetric kenel can increase the coupling of resonance filter 10, therefore this is preferably
Resonance filter 10 provided by embodiment provides higher bandwidth application.
Table one is please referred to, table one is concluded resonance provided by this first preferred embodiment and the second preferred embodiment and filtered
Wave device 10 consumes (propagation in the propagation of three kinds of lateral electric mode (transverse electric mode, TE)
Loss):
Table one
| TE0 | TE1 | TE2 | |
| Single depression portion | 10.7 | 821 | 994 |
| Two recessed portions | 0.11 | 234 | 122 |
Unit: decibel/centimetre (dB/cm)
By table one it is found that propagating consume can reduce when resonance filter tool is there are two when the recessed portion being asymmetrically formed
To 1 the percent of the only resonance filter in single depression portion.That is, there are two the recessed portions being asymmetrically formed for tool
Propagation consume can be greatly reduced in resonance filter, therefore may be allowed the wide application of higher frequency.
In conclusion resonance filter provided by according to the present invention, couples knot using the multilayer film comprising insulating materials
Structure replaces the middle ground electrode in existing SCF structure.It also include the list of asymmetric setting in this multilayer film coupled structure
One or two recessed portions, therefore sound wave can be confined in delivery areas, and efficiently reduce insertion loss and transmitting loss.Cause
This, resonance filter provided by the present invention can meet the bandwidth requirements greater than 2.5 megahertz (GHz).
The above description is only a preferred embodiment of the present invention, all equivalent changes done according to the claims in the present invention with repair
Decorations, are all covered by the present invention.
Claims (13)
1. a kind of resonance filter, includes:
Substrate；
Lower electrode, is set in the substrate；
Multilayer film coupled structure (multi-layered coupling structure), is set on the lower electrode, the multilayer
Film coupled structure includes an at least insulating materials；
Top electrode is set in the multilayer film coupled structure；
First piezoelectric layer is located between the lower electrode and the multilayer film coupled structure；
Second piezoelectric layer is located between the multilayer film coupled structure and the top electrode；And
First recessed portion is formed in the insulating materials of the multilayer film coupled structure.
2. resonance filter as described in claim 1, wherein the multilayer film coupled structure also includes:
At least one first low impedance layers, one second low impedance layers and a third low impedance layers；And
First high impedance layer and the second high impedance layer, first high impedance layer are located in first low impedance layers and second low-resistance
Between anti-layer, and second high impedance layer is located between second low impedance layers and the third low impedance layers.
3. resonance filter as claimed in claim 2, wherein first low impedance layers, second low impedance layers and the third are low
Impedance layer includes the insulating materials one of at least within.
4. resonance filter as claimed in claim 3, wherein first low impedance layers, second low impedance layers and the third are low
Impedance layer includes silica.
5. resonance filter as claimed in claim 2, wherein first high impedance layer and second high impedance layer include amorphous
Silicon (amorphoussilicon), platinum (Pt), molybdenum (Mo) or tantalum oxide (Ta2O5)。
6. resonance filter as claimed in claim 2, wherein a thickness of first low impedance layers and second low impedance layers
A thickness be respectively the third low impedance layers a thickness half.
7. resonance filter as described in claim 1 includes also the first groove and the second groove, is set to second piezoelectric layer
It is interior, and first groove is separated from each other with second groove by second piezoelectric layer.
8. resonance filter as claimed in claim 7, wherein it is second recessed with this to be exposed to first groove for second piezoelectric layer
The bottom of slot.
Also include ground termination points 9. resonance filter as claimed in claim 7, be respectively formed in first groove and this second
In groove.
10. resonance filter as claimed in claim 7, wherein the top electrode be set to first groove and second groove it
Between.
11. resonance filter as described in claim 1 includes also the second recessed portion, is formed in the multilayer film coupled structure
In the insulating materials, and first recessed portion and second recessed portion be formed asymmetrically in the multilayer film coupled structure this absolutely
In edge material.
12. resonance filter as described in claim 1, wherein the top electrode also includes input endpoint and exit point.
13. resonance filter as described in claim 1 also includes reflector (reflector), it is formed in the lower electrode and is somebody's turn to do
Between substrate.
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| CN201410084689.0A CN104917487B (en) | 2014-03-10 | 2014-03-10 | Resonance filter |
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| CN201410084689.0A CN104917487B (en) | 2014-03-10 | 2014-03-10 | Resonance filter |
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| CN104917487B true CN104917487B (en) | 2019-04-23 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6720844B1 (en) * | 2001-11-16 | 2004-04-13 | Tfr Technologies, Inc. | Coupled resonator bulk acoustic wave filter |
| US6917261B2 (en) * | 2002-12-05 | 2005-07-12 | Epcos Ag | Component operating with bulk acoustic waves, and having asymmetric/symmetrical circuitry |
| CN1794572B (en) * | 2004-12-22 | 2012-05-09 | 安华高科技无线Ip（新加坡）私人有限公司 | Acoustic resonator performance enhancement using selective metal etch |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102005055871A1 (en) * | 2005-11-23 | 2007-05-24 | Epcos Ag | Guided bulk acoustic wave operated component for e.g. ladder filter, has dielectric layer with low acoustic impedance, and metal layer including partial layer with high impedance, where ratio between impedances lies in certain range |
| US8512800B2 (en) * | 2007-12-04 | 2013-08-20 | Triquint Semiconductor, Inc. | Optimal acoustic impedance materials for polished substrate coating to suppress passband ripple in BAW resonators and filters |
-
2014
- 2014-03-10 CN CN201410084689.0A patent/CN104917487B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6720844B1 (en) * | 2001-11-16 | 2004-04-13 | Tfr Technologies, Inc. | Coupled resonator bulk acoustic wave filter |
| US6917261B2 (en) * | 2002-12-05 | 2005-07-12 | Epcos Ag | Component operating with bulk acoustic waves, and having asymmetric/symmetrical circuitry |
| CN1794572B (en) * | 2004-12-22 | 2012-05-09 | 安华高科技无线Ip（新加坡）私人有限公司 | Acoustic resonator performance enhancement using selective metal etch |
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