CN110868191B - Thin film bulk acoustic resonator and filter - Google Patents
Thin film bulk acoustic resonator and filter Download PDFInfo
- Publication number
- CN110868191B CN110868191B CN201910328576.3A CN201910328576A CN110868191B CN 110868191 B CN110868191 B CN 110868191B CN 201910328576 A CN201910328576 A CN 201910328576A CN 110868191 B CN110868191 B CN 110868191B
- Authority
- CN
- China
- Prior art keywords
- substrate
- curved surface
- thin film
- bulk acoustic
- film bulk
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000010409 thin film Substances 0.000 title claims description 28
- 239000000758 substrate Substances 0.000 claims abstract description 109
- 239000000463 material Substances 0.000 claims abstract description 33
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 23
- 239000004065 semiconductor Substances 0.000 claims abstract description 5
- 230000007704 transition Effects 0.000 claims description 22
- 229910052691 Erbium Inorganic materials 0.000 claims description 9
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 claims description 9
- 229910052706 scandium Inorganic materials 0.000 claims description 9
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 claims description 9
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 8
- 229910052727 yttrium Inorganic materials 0.000 claims description 5
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 claims description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 claims description 2
- 239000000956 alloy Substances 0.000 claims description 2
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 238000004544 sputter deposition Methods 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 description 25
- 238000007254 oxidation reaction Methods 0.000 description 21
- 239000013078 crystal Substances 0.000 description 16
- 230000003647 oxidation Effects 0.000 description 15
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 9
- 238000000034 method Methods 0.000 description 9
- 239000001301 oxygen Substances 0.000 description 9
- 229910052760 oxygen Inorganic materials 0.000 description 9
- 239000010408 film Substances 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 7
- 239000010703 silicon Substances 0.000 description 7
- 230000008859 change Effects 0.000 description 6
- 230000035772 mutation Effects 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000007781 pre-processing Methods 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005468 ion implantation Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000013077 target material Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052773 Promethium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 229910001423 beryllium ion Inorganic materials 0.000 description 1
- 230000001413 cellular effect Effects 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- OGPBJKLSAFTDLK-UHFFFAOYSA-N europium atom Chemical compound [Eu] OGPBJKLSAFTDLK-UHFFFAOYSA-N 0.000 description 1
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 description 1
- KJZYNXUDTRRSPN-UHFFFAOYSA-N holmium atom Chemical compound [Ho] KJZYNXUDTRRSPN-UHFFFAOYSA-N 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 1
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 1
- OHSVLFRHMCKCQY-UHFFFAOYSA-N lutetium atom Chemical compound [Lu] OHSVLFRHMCKCQY-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 229920005591 polysilicon Polymers 0.000 description 1
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- VQMWBBYLQSCNPO-UHFFFAOYSA-N promethium atom Chemical compound [Pm] VQMWBBYLQSCNPO-UHFFFAOYSA-N 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- KZUNJOHGWZRPMI-UHFFFAOYSA-N samarium atom Chemical compound [Sm] KZUNJOHGWZRPMI-UHFFFAOYSA-N 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 description 1
- FRNOGLGSGLTDKL-UHFFFAOYSA-N thulium atom Chemical compound [Tm] FRNOGLGSGLTDKL-UHFFFAOYSA-N 0.000 description 1
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/178—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator of a laminated structure of multiple piezoelectric layers with inner electrodes
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The invention relates to the technical field of semiconductors and discloses a film bulk acoustic resonator and a filter. The resonator includes a substrate; the multilayer structure is formed on the substrate and comprises a lower electrode layer, a piezoelectric layer and an upper electrode layer from bottom to top in sequence; wherein the piezoelectric layer comprises a piezoelectric material doped with a plurality of rare earth elements for improving the piezoelectric properties of the piezoelectric layer, and a cavity is formed between the substrate and the multilayer structure, the cavity comprising a lower half cavity below the upper surface of the substrate and an upper half cavity protruding beyond the upper surface of the substrate and toward the multilayer structure. The resonator is provided with the cavity with the lower half cavity and the upper half cavity, the whole lower half cavity is positioned below the upper surface of the substrate, and the whole upper half cavity is positioned above the upper surface of the substrate, so that a novel resonator structure is formed, and the resonator has better performance.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a film bulk acoustic resonator and a filter.
Background
Resonators may be used in a variety of electronic applications to implement signal processing functions, for example, some cellular telephones and other communication devices use resonators to implement filters for transmitted and/or received signals. Thin film bulk acoustic resonators (Film Bulk Acoustic Resonator, FBAR) are a type of radio frequency resonator implemented using MEMS technology that has been under great research in recent years. The device is made on silicon or gallium arsenide substrate and mainly consists of metal electrode/piezoelectric film/metal electrode. At certain specific frequencies, FBAR devices exhibit resonance characteristics like quartz crystal resonators and thus can be built into oscillators or filters for use in modern communication systems.
The structure of the thin film bulk acoustic resonator and the material of the piezoelectric thin film are important factors in determining the performance of the resonator.
Disclosure of Invention
Based on the state of the art, the invention provides a thin film bulk acoustic resonator with a novel structure and a filter based on the resonator.
A first aspect of an embodiment of the present invention provides a thin film bulk acoustic resonator, including:
a substrate;
the multilayer structure is formed on the substrate and comprises a lower electrode layer, a piezoelectric layer and an upper electrode layer from bottom to top, wherein the piezoelectric layer comprises piezoelectric materials doped with various rare earth elements;
wherein a cavity is formed between the substrate and the multilayer structure, the cavity including a lower cavity half below the upper surface of the substrate and an upper cavity half above the upper surface of the substrate and protruding toward the multilayer structure.
Optionally, the lower half cavity is surrounded by a bottom wall and a first side wall, the whole bottom wall is parallel to the surface of the substrate, and the first side wall is a first smooth curved surface extending from the edge of the bottom wall to the upper surface of the substrate.
Optionally, the first smooth curved surface includes a first curved surface and a second curved surface that are in smooth transition connection.
Optionally, the vertical section of the first curved surface is in an inverted parabolic shape and is positioned above the plane where the bottom wall is positioned;
the vertical section of the second curved surface is parabolic and is positioned below the plane of the upper surface of the substrate.
Optionally, the curvature of each point of the first smooth curved surface is smaller than a first preset value.
Optionally, the upper half cavity is surrounded by the lower side surface of the multilayer structure, a portion of the multilayer structure corresponding to the upper half cavity includes a top wall and a second side wall, and the second side wall is a second smooth curved surface extending from the edge of the top wall to the upper surface of the substrate.
Optionally, the second smooth curved surface includes a third curved surface and a fourth curved surface in smooth transition connection.
Optionally, the vertical section of the third curved surface is parabolic and is located below the plane where the top wall is located;
the vertical section of the fourth curved surface is in an inverted parabolic shape and is positioned above the plane where the upper surface of the substrate is positioned.
Optionally, the curvature of each point of the second smooth curved surface is smaller than a second preset value.
Optionally, the top wall is free of abrupt parts.
Optionally, the piezoelectric material comprises aluminum nitride.
Optionally, the rare earth elements include at least two rare earth elements incorporated into the aluminum nitride lattice.
Optionally, the concentration of each rare earth element in the piezoelectric material is less than 10%.
Optionally, the concentration of each rare earth element in the piezoelectric material is less than 1%.
Optionally, the rare earth elements include scandium and erbium.
Optionally, the rare earth element further comprises yttrium.
Alternatively, the piezoelectric layer is provided by sputtering a target formed from an alloy including aluminum and the plurality of rare earth elements over the lower electrode layer using a plasma including nitrogen.
A second aspect of the embodiments of the present invention provides a filter comprising any one of the thin film bulk acoustic resonators of the first aspect of the embodiments of the present invention.
The beneficial effects of adopting above-mentioned technical scheme to produce lie in: according to the embodiment of the invention, the cavity between the substrate and the multilayer structure is arranged to be the lower half cavity below the upper surface of the substrate and the upper half cavity above the upper surface of the substrate, and the rare earth element is doped in the piezoelectric layer, so that a novel resonator structure is formed, and the novel resonator structure has better performance.
Drawings
FIG. 1 is a schematic diagram of a film bulk acoustic resonator according to an embodiment of the present invention;
FIG. 2 is an enlarged schematic view of A in FIG. 1;
FIG. 3 is a flow chart of a method of fabricating a thin film bulk acoustic resonator in accordance with an embodiment of the present invention;
FIG. 4 is a flow chart of another method for fabricating a thin film bulk acoustic resonator in accordance with an embodiment of the present invention;
fig. 5 is a schematic diagram of a manufacturing process of a film bulk acoustic resonator according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The invention will be described in further detail with reference to the drawings and the detailed description.
Referring to fig. 1, one embodiment of the present invention provides a thin film bulk acoustic resonator comprising a substrate 100 and a multilayer structure 200. The multilayer structure 200 is formed on the substrate 100, and the multilayer structure 200 includes a lower electrode layer 203, a piezoelectric layer 202, and an upper electrode layer 201 in this order from bottom to top.
Wherein the piezoelectric layer 202 is formed of a piezoelectric material doped with a plurality of rare earth elements and hasIs a thickness of (c). The piezoelectric material includes aluminum nitride, zinc oxide and lead zirconate titanate, and the rare earth element includes scandium (Sc), yttrium (Y), lanthanum (La),Cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu).
A cavity 300 is formed between the substrate 100 and the multilayer structure 200, the cavity 300 including a lower cavity half 310 below the upper surface of the substrate 100 and an upper cavity half 320 protruding beyond the upper surface of the substrate 100 and toward the multilayer structure 200.
Referring to fig. 1, in one embodiment, the lower cavity half 310 is surrounded by a bottom wall 101 and a first side wall 102, the bottom wall 101 is parallel to the surface of the substrate 100, and the first side wall 102 is a first rounded surface extending from the edge of the bottom wall 101 to the upper surface of the substrate 100.
Wherein the bottom wall 101 and the first side wall 102 are both surface walls of the substrate 100. The first sidewall 102 is a first rounded surface, which can ensure the performance of the resonator cavity without abrupt change.
In this embodiment, the piezoelectric layer 202 is composed of aluminum nitride doped with scandium and erbium, wherein the scandium and erbium have concentrations of 2.5% and 2.5%, respectively.
In one embodiment, the piezoelectric layer 202 is composed of aluminum nitride doped with scandium and erbium, wherein the scandium and erbium concentrations are 0.63% and 0.34%, respectively.
In one embodiment, the piezoelectric layer 202 is composed of aluminum nitride doped with scandium, erbium, and yttrium, wherein the scandium, erbium, and yttrium concentrations are 0.25%, 0.25, and 0.5%, respectively.
Referring to fig. 2, in one embodiment, the first rounded curved surface may include a first curved surface 1021 and a second curved surface 1022 that are connected by a rounded transition. The first curved surface 1021 and the second curved surface 1022 in smooth transition connection means that the connection part between the first curved surface 1021 and the second curved surface 1022 is free from mutation, and both the first curved surface 1021 and the second curved surface 1022 are also free from mutation, so that the performance of the resonator cavity can be ensured. Wherein the substrate 100 is composed of a plurality of crystals (e.g., silicon crystals), no abrupt change means that the gaps between the crystals at the first rounded surface should not be too large to affect the performance of the resonator.
For example, the vertical section of the first curved surface 1021 may be inverted parabolic and located above the plane of the bottom wall 101; the second curved surface 1022 may have a parabolic vertical cross-section and may be located below the plane of the upper surface of the substrate 100. The first curved surface 1021 and the second curved surface 1022 are smoothly connected. Of course, the first curved surface 1021 and the second curved surface 1022 may be curved surfaces of other shapes, so long as the gaps between the crystals at the first rounded curved surface do not affect the performance of the resonator.
In one embodiment, the first rounded surface is smooth as a whole, and the curvature of each point of the first rounded surface 1021 may be smaller than the first preset value. The first preset value can be set according to practical situations, so that the purpose that gaps among crystals at the first smooth curved surface do not influence the performance of the resonator is achieved. In order to ensure the mechanical and electrical properties of the multilayer structure, the curvature of the smooth curved surface of the transition region is as small as possible, and the minimum curvature requires the length of the transition region to be increased under the condition of a certain thickness of the sacrificial layer, so that the area of the resonator is increased, and therefore, the curvature of the transition region and the length of the transition region are optimized. Preferably, the thickness of the cavity 300 may be 1 μm, the length of the transition region is controlled to be 3 μm to 5 μm, and the multi-layer structure grown in the transition region can meet resonator requirements. The transition zone length is the length of the first sidewall 102 in the direction of the dashed line shown in fig. 1.
Referring to fig. 1, in one embodiment, the upper cavity 302 may be surrounded by a lower side of the multi-layer structure 200, where a portion of the lower side of the multi-layer structure 200 corresponding to the upper cavity 302 includes a top wall 201 and a second side wall 202, and the second side wall 202 is a second rounded surface extending from an edge of the top wall 201 to an upper surface of the substrate 100.
Wherein the top wall 201 and the second side wall 202 are both lower side walls of the multi-layer structure 200. The second side wall 202 is a second smooth curved surface, which can ensure the performance of the resonator cavity without abrupt change.
Referring to fig. 2, in one embodiment, the second rounded surface may include a rounded third surface 2021 and a rounded fourth surface 2022. The third curved surface 2021 and the fourth curved surface 2022 that are in smooth transition connection mean that the connection position between the third curved surface 2021 and the fourth curved surface 2022 is free from mutation, and both the third curved surface 2021 and the fourth curved surface 2022 are also free from mutation, so that the performance of the resonator cavity can be ensured. Wherein from a crystal point of view, the substrate 100 is composed of a plurality of crystals (e.g., silicon crystals), and no abrupt change means that the gaps between the crystals at the second rounded surface should not be too large to affect the performance of the resonator.
For example, the vertical section of the third curved surface 2021 may be parabolic and located below the plane of the top wall 201; the vertical section of the fourth curved surface 2022 is inverted parabolic and is located above the plane of the upper surface of the substrate 100. Of course, the third curved surface 2021 and the fourth curved surface 2022 may have other shapes, and it is sufficient that the gaps between the crystals at the first rounded curved surface do not affect the performance of the resonator.
In one embodiment, the curvature of each point of the second rounded surface 2021 is smaller than the second preset value. The second preset value can be set according to practical situations, so that the purpose that gaps among crystals at the second smooth curved surface do not influence the performance of the resonator is achieved.
Further, the top wall 201 is also free of abrupt parts. The abrupt changes described herein are consistent with the foregoing abrupt changes, and from a crystal standpoint, the multilayer structure 200 is also composed of a plurality of crystals, with no abrupt changes meaning that the gaps between the individual crystals at the top wall 201 should not be too large to affect the performance of the resonator.
In the above embodiment, the substrate 100 may be a silicon substrate or a substrate made of other materials, which is not limited thereto.
In the resonator, the cavity 300 between the substrate 100 and the multilayer structure 200 is configured as the lower half cavity 310 below the upper surface of the substrate 100 and the upper half cavity 320 above the upper surface of the substrate 100, and rare earth elements are doped in the piezoelectric layer 202, so that a novel film bulk acoustic resonator structure is formed and has better performance.
Referring to fig. 3, in one embodiment of the present invention, a method for manufacturing a thin film bulk acoustic resonator is disclosed, which includes the following steps:
step 301, pre-processing the substrate, and changing the preset reaction rate of the preset area portion of the substrate, so that the preset reaction rate corresponding to the preset area portion is greater than the preset reaction rate corresponding to the non-preset area portion.
In this step, the preset reaction rate of the preset area portion of the substrate is enabled to reach the effect that the preset reaction rate corresponding to the preset area portion is greater than the preset reaction rate corresponding to the non-preset area portion by performing the pretreatment on the preset area portion of the substrate, so that when the preset reaction is performed on the substrate in the subsequent step 302, the reaction rate of the preset area portion and the reaction rate of the non-preset area portion are enabled to be different, so as to generate the sacrificial material portion with the preset shape.
Step 302, performing the preset reaction on the substrate to generate a sacrificial material part; the sacrificial material portion includes an upper half portion located above the upper surface of the substrate and a lower half portion located below the lower surface of the substrate.
Wherein the lower half part is surrounded by a bottom surface and a first side surface; the whole bottom surface is parallel to the surface of the substrate, and the first side surface is a first smooth curved surface extending from the edge of the bottom wall to the upper surface of the substrate. The upper half part is surrounded by the lower side surface of the multilayer structure, the part of the multilayer structure corresponding to the upper half part comprises a top surface and a second side surface, and the second side surface is a second smooth curved surface extending from the edge of the top surface to the upper surface of the substrate.
Optionally, the first smooth curved surface comprises a first curved surface and a second curved surface which are in smooth transition connection; the vertical section of the first curved surface is in an inverted parabolic shape and is positioned above the plane where the bottom surface is positioned; the vertical section of the second curved surface is parabolic and is positioned below the plane of the upper surface of the substrate.
Optionally, the second smooth curved surface comprises a third curved surface and a fourth curved surface which are in smooth transition connection; the vertical section of the third curved surface is parabolic and is positioned below the plane where the top surface is positioned; the vertical section of the fourth curved surface is in an inverted parabolic shape and is positioned above the plane where the upper surface of the substrate is positioned.
In one embodiment, the curvature of the first smooth curved surface is smaller than a first preset value; the curvature of the second smooth curved surface is smaller than a second preset value.
It can be appreciated that, since the preset reaction rate corresponding to the preset region portion is greater than the preset reaction rate corresponding to the non-preset region portion, when the preset reaction is performed on the substrate, the preset region portion reacts fast and the non-preset region portion reacts slow, so that the sacrificial material portion of the preset shape can be generated.
In one embodiment, the step 302 implementation may include: and (3) placing the substrate in an oxidizing atmosphere for oxidation treatment to obtain the sacrificial material part. Correspondingly, the pretreatment of the substrate in step 301 is a means capable of increasing the oxidation reaction rate of the predetermined area portion of the substrate. The means may be ion implantation in the preset area to increase the oxidation reaction rate of the preset area portion of the substrate, or may be a shielding layer with a preset pattern formed on the substrate to increase the oxidation reaction rate of the preset area portion of the substrate.
Of course, in other embodiments, the pretreatment in step 301 may be other than oxidation treatment, and the method may be to perform ion implantation in the preset area to increase the oxidation reaction rate of the preset area portion of the substrate, or to form a shielding layer with a preset pattern on the substrate to increase the oxidation reaction rate of the preset area portion of the substrate.
Step 303, forming a multi-layer structure on the sacrificial material layer; the multilayer structure sequentially comprises a lower electrode layer, a piezoelectric layer and an upper electrode layer from bottom to top, wherein the piezoelectric layer is formed by the following steps: multiple targets of aluminum and rare earth elements are sputtered onto the lower electrode layer using a nitrogen-containing plasma.
And 304, removing the sacrificial material part to form the resonator.
In this embodiment, the substrate may be a silicon substrate or a substrate made of other materials, which is not limited thereto.
According to the method for manufacturing the resonator, the reaction rate of the preset area part of the substrate is larger than the corresponding preset reaction rate of the non-preset area part by preprocessing the substrate, so that the sacrificial material part with the preset shape can be generated when the substrate is subjected to the preset reaction, a multi-layer structure is formed on the sacrificial material layer, and finally the sacrificial material part is removed to form the film bulk acoustic resonator with the special cavity structure, and compared with the traditional manufacturing method, the surface roughness of the working area of the resonator is easier to control.
Referring to fig. 4, an embodiment of the invention discloses a method for manufacturing a thin film bulk acoustic resonator, which comprises the following steps:
in step 401, a shielding layer 400 is formed on a substrate, and the shielding layer covers an area except a preset area on the substrate, see fig. 5 (a).
In this step, the process of forming the shielding layer on the substrate may include:
forming a shielding medium on the substrate, wherein the shielding layer is used for shielding the area of the substrate except for a preset area from the preset reaction;
and removing the shielding medium corresponding to the preset area to form the shielding layer.
Wherein the shielding medium acts such that the reaction rate of the portion of the substrate covered by the shielding medium is lower than the reaction rate of the portion not covered by the shielding medium. Further, the shielding layer may be used to shield the substrate from the preset reaction in an area other than the preset area.
Step 402, preprocessing a substrate on which a shielding layer is formed, and controlling a part of the substrate corresponding to the preset area to perform a preset reaction to obtain a sacrificial material part; the sacrificial material portion includes an upper half portion located above the upper surface of the substrate and a lower half portion located below the lower surface of the substrate.
Wherein the lower half part is surrounded by a bottom surface and a first side surface; the whole bottom surface is parallel to the surface of the substrate, and the first side surface is a first smooth curved surface extending from the edge of the bottom wall to the upper surface of the substrate. The upper half part is surrounded by the lower side surface of the multilayer structure, the part of the multilayer structure corresponding to the upper half part comprises a top surface and a second side surface, and the second side surface is a second smooth curved surface extending from the edge of the top surface to the upper surface of the substrate.
Optionally, the first smooth curved surface includes a first curved surface and a second curved surface that are in smooth transition connection. For example, the vertical section of the first curved surface is in an inverted parabolic shape and is positioned above the plane of the bottom surface; the vertical section of the second curved surface is parabolic and is positioned below the plane of the upper surface of the substrate.
Optionally, the second smooth curved surface comprises a third curved surface and a fourth curved surface which are in smooth transition connection; the vertical section of the third curved surface is parabolic and is positioned below the plane where the top surface is positioned; the vertical section of the fourth curved surface is in an inverted parabolic shape and is positioned above the plane where the upper surface of the substrate is positioned.
In one embodiment, the curvature of the first smooth curved surface is smaller than a first preset value; the curvature of the second smooth curved surface is smaller than a second preset value.
As an implementation manner, the implementation procedure of step 402 may include: and (3) placing the substrate in an oxidizing atmosphere for oxidation treatment, and controlling the part of the substrate corresponding to the preset area to perform oxidation reaction to obtain a sacrificial material part, as shown in fig. 5 (b).
Wherein, the placing the substrate in an oxidizing atmosphere for oxidation treatment may include:
introducing high-purity oxygen into the substrate in a process temperature environment in a preset range so as to enable an oxide layer to be generated on the substrate at a part corresponding to the preset area;
after a first preset time, stopping introducing high-purity oxygen to the substrate, and enabling the thickness of an oxide layer on the substrate to reach a preset thickness by one or more modes of wet oxygen oxidation, oxyhydrogen synthesis oxidation and high-pressure water vapor oxidation;
and stopping introducing wet oxygen into the substrate and introducing high-purity oxygen into the substrate, and finishing the oxidation treatment of the substrate after a second preset time.
Wherein the preset range can be 1000-1200 ℃; the first preset time may be 20 minutes to 140 minutes; the preset thickness may be 0.4 μm to 4 μm; the second preset time may be 20 minutes to 140 minutes; the flow rate of the high-purity oxygen can be 3L/min-15L/min.
It should be noted that, the shape of the transition area has a certain difference by adopting one or a combination of several means of pure oxygen, wet oxygen, oxyhydrogen synthesis and high-pressure water vapor oxidation; meanwhile, the type and structure of the shielding layer are selected, a certain marketing is provided for the shape of the transition region, and the oxidation mode and the type and structure of the shielding layer are reasonably selected according to the thickness of the multilayer structure and the requirement of the piezoelectric layer on curvature change.
Step 403, removing the pretreated substrate-screening layer, see fig. 5 (c).
Step 404, forming a multi-layer structure on the substrate from which the shielding layer is removed, where the multi-layer structure includes, from bottom to top, a lower electrode layer, a piezoelectric layer, and an upper electrode layer, see fig. 5 (d), where the method for forming the piezoelectric layer includes: aluminum and rare earth elements are formed into a composite target material, and then the composite target material is sputtered onto the lower electrode layer by nitrogen-containing plasma. .
Step 405, removing the sacrificial material portion, see fig. 5 (e).
In this embodiment, the shielding layer may be a SiN material layer or SiO 2 The material layer, the polysilicon material layer, or the multi-layer structure formed by mixing two or three materials can be a silicon substrate or a substrate made of other materials, which is not limited.
In one embodiment, the shielding layer can be SiN or a multilayer film structure, siN is used as an oxidation shielding layer, the shielding effect is good, and the reaction rate of the shielding region and the non-shielding region is large. The shielding medium needed to manufacture the resonator area can be removed by means of etching or corrosion, the silicon wafer is put in an oxidizing atmosphere for oxidation, and the reaction rate of the part with the shielding medium and the reaction rate of the part without the shielding medium are greatly different: the reaction rate of the part without shielding medium is faster, and the substrate Si reacts with oxygen to form SiO 2 SiO produced 2 The thickness is increased gradually, the upper surface is increased gradually than the surface with the shielding medium part, the Si surface without the shielding medium part is decreased gradually, and the Si surface without the shielding medium part is relatively free of the shielding mediumThe surface of the mass part is reduced, and oxygen enters the lower part of the shielding layer from the side surface of the edge part of the shielding layer, so that the oxidation rate of the edge of the shielding layer is slower than that of the part without the shielding medium, and is faster than that of the part with the shielding medium, and the closer to the edge of the shielding medium, the oxidation rate of the part without the shielding medium tends to be higher. And forming a transition region without rate change at the edge of the shielding layer, wherein the transition region can form a smooth curved surface by optimizing the oxidation mode and the type and structure of the shielding layer, and a multilayer structure of the pressure-equal-voltage thin film containing AlN is grown on the smooth curved surface, so that the crystal quality of the piezoelectric thin film can be ensured.
The embodiment of the invention also discloses a semiconductor device which comprises any thin film bulk acoustic resonator and has the beneficial effects of the resonator. For example, the semiconductor device may be a filter.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (12)
1. A thin film bulk acoustic resonator, comprising:
a substrate;
the multilayer structure is formed on the substrate and comprises a lower electrode layer, a piezoelectric layer and an upper electrode layer from bottom to top, wherein the piezoelectric layer comprises piezoelectric materials doped with various rare earth elements;
wherein a cavity is formed between the substrate and the multilayer structure, the cavity comprising a lower half cavity below the upper surface of the substrate and an upper half cavity protruding beyond the upper surface of the substrate and toward the multilayer structure;
the lower half cavity is surrounded by a bottom wall and a first side wall, the whole bottom wall is parallel to the surface of the substrate, and the first side wall is a first smooth curved surface extending from the edge of the bottom wall to the upper surface of the substrate; the first smooth curved surface comprises a first curved surface and a second curved surface which are in smooth transition connection; the vertical section of the first curved surface is in an inverted parabolic shape and is positioned above the plane of the bottom wall; the vertical section of the second curved surface is parabolic and is positioned below the plane of the upper surface of the substrate;
the upper half cavity is surrounded by the lower side surface of the multilayer structure, the part of the lower side surface of the multilayer structure corresponding to the upper half cavity comprises a top wall and a second side wall, and the second side wall is a second smooth curved surface extending from the edge of the top wall to the upper surface of the substrate; the second smooth curved surface comprises a third curved surface and a fourth curved surface which are in smooth transition connection; the vertical section of the third curved surface is parabolic and is positioned below the plane where the top wall is positioned; the vertical section of the fourth curved surface is in an inverted parabolic shape and is positioned above the plane where the upper surface of the substrate is positioned.
2. The thin film bulk acoustic resonator of claim 1, wherein the curvature of each point of the first rounded surface is less than a first predetermined value.
3. The thin film bulk acoustic resonator of claim 1, wherein the curvature of each point of the second rounded curved surface is less than a second predetermined value.
4. A thin film bulk acoustic resonator as claimed in any one of claims 1 to 3, wherein the top wall is free of abrupt parts.
5. The thin film bulk acoustic resonator of claim 1 wherein the piezoelectric material comprises aluminum nitride.
6. The thin film bulk acoustic resonator of claim 5, wherein the rare earth element comprises at least two rare earth elements incorporated into the aluminum nitride lattice.
7. The thin film bulk acoustic resonator of claim 6, wherein the concentration of each rare earth element in the piezoelectric material is less than 10%.
8. The thin film bulk acoustic resonator of claim 7, wherein the concentration of each rare earth element in the piezoelectric material is less than 1%.
9. The thin film bulk acoustic resonator of claim 7, wherein the rare earth elements comprise scandium and erbium.
10. The thin film bulk acoustic resonator of claim 7, wherein the rare earth element further comprises yttrium.
11. The thin film bulk acoustic resonator of claim 5, wherein the piezoelectric layer is provided by sputtering a target formed from an alloy comprising aluminum and the plurality of rare earth elements over the lower electrode layer using a plasma comprising nitrogen.
12. A semiconductor device comprising the thin film bulk acoustic resonator of any one of claims 1 to 11.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910328576.3A CN110868191B (en) | 2019-04-23 | 2019-04-23 | Thin film bulk acoustic resonator and filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910328576.3A CN110868191B (en) | 2019-04-23 | 2019-04-23 | Thin film bulk acoustic resonator and filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110868191A CN110868191A (en) | 2020-03-06 |
| CN110868191B true CN110868191B (en) | 2023-09-12 |
Family
ID=69651960
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910328576.3A Active CN110868191B (en) | 2019-04-23 | 2019-04-23 | Thin film bulk acoustic resonator and filter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110868191B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6001709A (en) * | 1997-12-19 | 1999-12-14 | Nanya Technology Corporation | Modified LOCOS isolation process for semiconductor devices |
| KR20060095272A (en) * | 2005-02-28 | 2006-08-31 | 삼성전기주식회사 | Film bulk acoustic resonator |
| CN101465628A (en) * | 2009-01-15 | 2009-06-24 | 电子科技大学 | Film bulk acoustic wave resonator and preparation method thereof |
| CN103795366A (en) * | 2012-10-27 | 2014-05-14 | 安华高科技通用Ip(新加坡)公司 | Bulk acoustic wave resonator structure, thin film bulk acoustic resonator structure, and solidly mounted bulk acoustic wave resonator structure |
| CN104868871A (en) * | 2014-02-26 | 2015-08-26 | 安华高科技通用Ip(新加坡)公司 | Bulk Acoustic Wave Resonators Having Doped Piezoelectric Material And Frame Elements |
-
2019
- 2019-04-23 CN CN201910328576.3A patent/CN110868191B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6001709A (en) * | 1997-12-19 | 1999-12-14 | Nanya Technology Corporation | Modified LOCOS isolation process for semiconductor devices |
| KR20060095272A (en) * | 2005-02-28 | 2006-08-31 | 삼성전기주식회사 | Film bulk acoustic resonator |
| CN101465628A (en) * | 2009-01-15 | 2009-06-24 | 电子科技大学 | Film bulk acoustic wave resonator and preparation method thereof |
| CN103795366A (en) * | 2012-10-27 | 2014-05-14 | 安华高科技通用Ip(新加坡)公司 | Bulk acoustic wave resonator structure, thin film bulk acoustic resonator structure, and solidly mounted bulk acoustic wave resonator structure |
| CN104868871A (en) * | 2014-02-26 | 2015-08-26 | 安华高科技通用Ip(新加坡)公司 | Bulk Acoustic Wave Resonators Having Doped Piezoelectric Material And Frame Elements |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110868191A (en) | 2020-03-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9679765B2 (en) | Method of fabricating rare-earth doped piezoelectric material with various amounts of dopants and a selected C-axis orientation | |
| US10530327B2 (en) | Surface acoustic wave (SAW) resonator | |
| US9088265B2 (en) | Bulk acoustic wave resonator comprising a boron nitride piezoelectric layer | |
| JP3321369B2 (en) | Surface acoustic wave device, its substrate, and its manufacturing method | |
| CN110868185B (en) | Bulk acoustic wave resonator and semiconductor device | |
| KR20170137743A (en) | A lithium tantalate single crystal substrate, a bonded substrate thereof, a manufacturing method thereof, and a surface acoustic wave device | |
| KR102109884B1 (en) | Bulk-acoustic wave resonator and method for manufacturing the same | |
| CN110868184A (en) | Bulk acoustic wave resonator and semiconductor device | |
| US20150240349A1 (en) | Magnetron sputtering device and method of fabricating thin film using magnetron sputtering device | |
| US11664783B2 (en) | Resonator and semiconductor device | |
| CN110868191B (en) | Thin film bulk acoustic resonator and filter | |
| CN109560784B (en) | Lamb wave resonator and preparation method thereof | |
| CN110868174B (en) | Acoustic resonator and filter | |
| CN114744974A (en) | Bulk acoustic wave resonator, method of manufacturing the same, filter, and electronic apparatus | |
| KR0147498B1 (en) | Low temperature selective growth of silicon or silicon alloys | |
| US11984864B2 (en) | Method for manufacturing resonator | |
| CN117176101A (en) | Bulk acoustic wave resonator, preparation method thereof, filter and electronic equipment | |
| CN110868173B (en) | Resonator and filter | |
| CN113872558A (en) | Resonator manufacturing method and resonator | |
| CN110868175B (en) | Resonator with seed layer, filter and resonator preparation method | |
| US20220416765A1 (en) | Bulk acoustic wave resonance device and bulk acoustic wave filter | |
| JP5093084B2 (en) | Method for producing potassium niobate thin film | |
| US11817848B2 (en) | Resonator and filter | |
| CN117013978B (en) | Bulk acoustic wave resonator, preparation method thereof, filter and electronic equipment | |
| CN219659683U (en) | Resonator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |