1. A resonant type biaxial magnetic sensor based on a FeGa/high-k material composite magnetic film is characterized by comprising: a Δ E effect sensitive structure; the delta E effect sensitive structure comprises a first electrode layer, a piezoelectric layer and at least one FeGa/high-k material composite magnetic film which are sequentially stacked, wherein the FeGa/high-k material composite magnetic film comprises a stacked FeGa magnetic film layer and a stacked high-k material film layer, and at least one FeGa magnetic film is stacked on the piezoelectric layer and serves as a second electrode layer; the FeGa magnetic thin film layer has (110) or (100) crystallographic preferred orientation, and has delta E effect in both in-plane and out-of-plane directions of the FeGa magnetic thin film layer.

2. The resonant dual-axis magnetic sensor according to claim 1, wherein: the thickness of the FeGa magnetic film layer is 40-800nm, and the thickness of the high-k material film layer is 5-100 nm;

preferably, the material of the high-k material thin film layer comprises Al₂O₃、HfO₂、ZrO₂And diamond, and any one or a combination of two or more thereof;

preferably, the dielectric constant of the high-k material thin film layer is 7 to 9.

3. The resonant dual-axis magnetic sensor according to claim 1 or 2, characterized in that: the delta E effect sensitive structure comprises a plurality of stacked FeGa/high-k material composite magnetic films.

4. The resonant dual-axis magnetic sensor according to claim 1, wherein: the first electrode layer comprises a Mo, Al, W, Pt or Ta film; and/or the thickness of the first electrode layer is 50-800 nm.

5. The resonant dual-axis magnetic sensor according to claim 1, wherein: the piezoelectric layer comprises AlN, ZnO, PZT and LiNbO₃Any one or a combination of two or more of the films;

and/or the thickness of the piezoelectric layer is 100-2000 nm.

6. The resonant dual-axis magnetic sensor according to claim 1, wherein: the second electrode layer is also connected with a metal pad, and an insulating layer is also arranged between the metal pad and the first electrode layer;

preferably, the insulating layer covers the side edges of the first electrode layer and the second electrode layer;

preferably, the coverage width of the insulating layer is 2-5 μm; preferably, the material of the insulating layer comprises SiO₂、Si₃N₄AlN or Al₂O₃(ii) a Preferably, the thickness of the insulating layer is 50 to 500 nm.

7. The resonant dual-axis magnetic sensor according to claim 1, wherein: the delta E effect sensitive structure is arranged on an AlN seed crystal layer, the seed crystal layer is stacked on the substrate, the delta E effect sensitive structure is arranged in a resonance area of the device,

the surface or the inside of the substrate is also provided with an acoustic wave reflection structure which is correspondingly arranged below the delta E effect sensitive structure and at least used for limiting longitudinal acoustic waves generated by piezoelectric resonance in a resonance area;

and/or the substrate comprises a Si (100) wafer, and the thickness of the substrate is 50-300 μm;

preferably, the seed crystal layer comprises AlN seed crystal, and the thickness of the seed crystal layer is 30-100 nm.

8. The resonant dual-axis magnetic sensor according to claim 7, wherein: the acoustic wave reflecting structure comprises an air cavity disposed within the substrate;

preferably, the air cavity is a groove arranged on the surface of one side of the substrate close to the seed crystal layer, or the air cavity is a through hole penetrating through the substrate along the thickness direction;

preferably, the Δ E effect sensitive structure is a polygonal structure, and the shape of the air cavity is the same as that of the Δ E effect sensitive structure;

preferably, the air cavities have a depth of 50-300 μm.

9. The resonant dual-axis magnetic sensor according to claim 7, wherein: the sound wave reflection structure comprises a Bragg reflection layer which is stacked on the substrate, and the seed crystal is stacked on the Bragg reflection layer; the Bragg reflection layer comprises more than 4 layers of high-acoustic-impedance acoustic wave reflection films and low-acoustic-impedance acoustic wave reflection films which are alternately laminated in sequence;

preferably, the characteristic acoustic impedance Z of the high acoustic impedance acoustic wave reflective film₀Characteristic acoustic impedance Z of acoustic reflection film with low acoustic impedance₁The ratio is 5-10;

preferably, the high impedance acoustic wave reflective film and the low impedance acoustic wave reflective film both have a thickness of λ/4, where λ is the wavelength of the acoustic wave propagating in the film.

10. A dual-axis magnetic sensor test system, characterized by comprising a resonant dual-axis magnetic sensor according to any one of claims 1 to 9.

Background

The magnetic sensor can be used for position sensing and magnetic field intensity detection as a position sensor, and can also be used in the fields of mineral exploration, nondestructive material detection, non-contact switches, navigation systems and the like. The resonant structure magnetic sensor based on the Micro Electro Mechanical System (MEMS) technology is expected to become an important development direction of the magnetic sensor in the future due to the advantages of small size, low weight, low power consumption, low cost, higher sensitivity, high resolution and the like. The existing magnetic sensor based on the magnetic film has the problems that the magnetic sensor can only sense a magnetic field in a single direction, the sensitivity is low, and the practicability is limited. If the sensor is applied more and more widely in the smart phone, personal navigation becomes a necessary technology, a single-axis magnetic sensor is very limited in sensing, cannot accurately sense the position, is single in the direction of a detection magnetic field, and is difficult to convert into practical application.

Disclosure of Invention

The invention mainly aims to provide a resonant type double-shaft magnetic sensor based on a FeGa/high-k material composite magnetic film and a double-shaft magnetic sensor testing system, so as to overcome the defects in the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

the embodiment of the invention provides a resonant type double-shaft magnetic sensor based on a FeGa/high-k material composite magnetic film, which comprises: the delta E effect sensitive structure comprises a first electrode layer, a piezoelectric layer and at least one FeGa/high-k material composite magnetic film which are sequentially stacked,

the FeGa/high-k material composite magnetic film comprises a FeGa magnetic film layer and a high-k material film layer which are stacked, wherein at least one FeGa magnetic film is stacked on the piezoelectric layer and serves as a second electrode layer; the FeGa magnetic thin film layer has (110) or (100) crystallographic preferred orientation, and has delta E effect in both in-plane and out-of-plane directions of the FeGa magnetic thin film layer.

Compared with the prior art, the invention has the advantages that:

1) the embodiment of the invention provides a resonant biaxial magnetic sensor based on a FeGa/high-k material composite magnetic film, which comprises (110) a preferred orientation FeGa magnetic film, wherein the preferred orientation FeGa magnetic film has an anisotropic delta E effect and can realize magnetic field intensity sensing in two directions of the surface and the outside of the device;

2) the embodiment of the invention provides a resonant biaxial magnetic sensor based on a FeGa/high-k material composite magnetic film, which is realized based on a bulk acoustic wave resonator, so that the resonant biaxial magnetic sensor has two reading modes of resonant frequency f and return loss S11, and can avoid the negative influence of electrical noise on magnetic field intensity sensing;

3) the embodiment of the invention provides a resonant biaxial magnetic sensor based on a FeGa/high-k material composite magnetic film, wherein the high-k material film can improve the Delta E effect high-frequency response characteristic of the composite magnetic film, reduce the eddy current loss of the magnetic sensor, reduce the acoustic wave energy loss of a resonator, improve the sensitivity of the magnetic sensor, isolate air and reduce the long-term oxidation of the FeGa magnetic film by an air environment.

Drawings

Fig. 1 is a schematic structural diagram of a resonant biaxial magnetic sensor based on a composite magnetic thin film of a FeGa/high-k material provided in embodiment 1 of the present invention;

fig. 2 is a schematic view of a process for preparing a resonant biaxial magnetic sensor based on a composite magnetic thin film of a FeGa/high-k material according to embodiment 1 of the present invention;

FIG. 3 is a powder X-ray diffraction pattern of a FeGa film prepared by magnetron sputtering in example 1 of the present invention;

FIG. 4 is a schematic diagram of a dual-axis magnetic sensor testing system employed in the present invention;

FIG. 5 is a graph of resonant frequency f and return loss S11 versus applied magnetic field under the action of an in-plane magnetic field;

FIG. 6 is a graph of resonant frequency f versus applied magnetic field strength under an out-of-plane magnetic field;

FIG. 7 is a plot of return loss S11 versus applied magnetic field strength under an out-of-plane magnetic field;

FIG. 8 is a graph showing the relationship between the resonant frequency f and the intensity of an externally applied magnetic field under the action of magnetic fields at different angles in a plane;

FIG. 9 is a plot of return loss S11 versus applied magnetic field strength for in-plane magnetic fields of different angles;

FIG. 10 is a FeGa/Al-based alloy provided in example 2 of the present invention₂O₃The sacrificial layer structure schematic diagram of the resonant biaxial magnetic sensor of the composite magnetic film;

FIG. 11 is a FeGa/Al-based alloy provided in example 3 of the present invention₂O₃The Bragg reflection layer structure schematic diagram of the resonant biaxial magnetic sensor of the composite magnetic film;

fig. 12 and 13 are performance characterization results of the FeGa-based resonant magnetic sensor provided in comparative example 1 of the present invention.

Detailed Description

In view of the deficiencies in the prior art, the inventors of the present invention have made extensive studies and extensive practices to provide technical solutions of the present invention. The technical solution, its implementation and principles, etc. will be further explained as follows.

The inventor researches and discovers that the delta E effect in the magnetic thin film material shows magnetoelastic coupling, namely the Young modulus E of the material changes along with the change of the magnetic field intensity under the action of an external magnetic field, and the delta E effect shows anisotropy for FeGa thin films with different preferred orientations, so that the material can be applied to a biaxial magnetic sensor.

The embodiment of the invention provides a resonant type double-shaft magnetic sensor based on a FeGa/high-k material composite magnetic film, which comprises: a Δ E effect sensitive structure; the delta E effect sensitive structure comprises a first electrode layer, a piezoelectric layer and at least one FeGa/high-k material composite magnetic film which are sequentially stacked,

the FeGa/high-k material composite magnetic film comprises a FeGa magnetic film layer and a high-k material film layer which are stacked, wherein at least one FeGa magnetic film is stacked on the piezoelectric layer and serves as a second electrode layer; the FeGa magnetic thin film layer has (110) or (100) crystallographic preferred orientation, and has delta E effect in both in-plane and out-of-plane directions of the FeGa magnetic thin film layer.

Further, the thickness of the FeGa magnetic film layer is 40-800nm, and the thickness of the high-k material film layer is 5-100 nm.

Furthermore, the material of the high-k material thin film layer comprises Al₂O₃、HfO₂、ZrO₂And diamond, and any one or a combination of two or more thereof.

Further, the dielectric constant of the high-k material film layer is 7-9.

Furthermore, the delta E effect sensitive structure comprises a plurality of stacked FeGa/high-k material composite magnetic films.

Further, the first electrode layer includes a Mo, Al, W, Pt, or Ta thin film, but is not limited thereto.

Further, the thickness of the first electrode layer is 50-800 nm.

Further, the piezoelectric layer comprises AlN, ZnO, PZT and LiNbO₃Any one or a combination of two or more of the films, but not limited thereto.

Further, the thickness of the piezoelectric layer is 100-2000 nm.

Furthermore, the second electrode layer is further connected with a metal pad, and an insulating layer is further arranged between the metal pad and the first electrode layer.

Further, the insulating layer covers the side edges of the first electrode layer and the second electrode layer.

Further, the coverage width of the insulating layer is 2-5 μm.

Furthermore, the material of the insulating layer comprises SiO₂、Si₃N₄AlN or Al₂O₃But is not limited thereto.

Further, the thickness of the insulating layer is 50-500 nm.

In some more specific embodiments, the delta E effect sensitive structure is disposed on an AlN seed layer, the seed layer is layered on a substrate, and the delta E effect sensitive structure is disposed within a resonant region of the device,

and the surface or the inside of the substrate is also provided with an acoustic wave reflection structure which is correspondingly arranged below the delta E effect sensitive structure and at least used for limiting longitudinal acoustic waves generated by piezoelectric resonance in a resonance area.

Further, the substrate comprises a Si (100) wafer, and the thickness of the substrate is 50-300 μm.

Further, the seed crystal layer comprises AlN seed crystal, and the thickness of the seed crystal layer is 30-100 nm.

Further, the acoustic wave reflecting structure includes an air cavity disposed within the substrate.

Further, the air cavity is a groove formed in the surface of the substrate on the side close to the seed crystal layer, or the air cavity is a through hole penetrating through the substrate in the thickness direction.

Further, the Δ E effect sensitive structure is a polygonal structure, and the shape of the air cavity is the same as that of the Δ E effect sensitive structure.

Further, the air cavity has a depth of 50-300 μm.

Further, the acoustic wave reflection structure comprises a bragg reflection layer stacked on the substrate, and the seed crystal layer is stacked on the bragg reflection layer; the Bragg reflection layer comprises more than 4 layers of high-acoustic-impedance acoustic wave reflection films and low-acoustic-impedance acoustic wave reflection films which are alternately laminated in sequence.

Further, the characteristic acoustic impedance Z of the high acoustic impedance acoustic wave reflective film₀Characteristic acoustic impedance Z of acoustic reflection film with low acoustic impedance₁The ratio is 5-10.

Further, the thicknesses of the high impedance acoustic wave reflection film and the low impedance acoustic wave reflection film are both lambda/4, wherein lambda is the wavelength of the acoustic wave propagating in the films.

The embodiment of the invention also provides a test system of the double-shaft magnetic sensor, which comprises the resonant double-shaft magnetic sensor.

As will be further explained in the following with reference to the drawings, unless otherwise specified, the piezoelectric layer, the electrode layer, and the metal pad of the resonant biaxial magnetic sensor based on the FeGa/high k material composite magnetic thin film according to the embodiments of the present invention may be made by any process known to those skilled in the art, and the sputtering, epitaxy, etching, and the like used in the embodiments of the present invention may also be made by any process known to those skilled in the art.

Referring to fig. 1 and 10, in some more specific embodiments, a resonant dual-axis magnetic sensor based on a composite magnetic thin film of a FeGa/high-k material includes, from bottom to top: the piezoelectric resonator comprises a substrate 1, a seed crystal layer 2, a lower electrode layer (namely a first electrode layer) 3, a piezoelectric layer 4 and at least one FeGa/high-k value material composite magnetic film layer 9, wherein the FeGa/high-k value material composite magnetic film layer 9 comprises a FeGa magnetic film layer 5 and a high-k value material film layer 6 which are sequentially stacked, the FeGa magnetic film layer 5 located at the lowermost layer is stacked on the piezoelectric layer 4 and serves as a second electrode layer, the second electrode layer is further connected with a metal pad8, an insulating layer 7 is further arranged between the metal pad8 and the lower electrode layer 3, the insulating layer 7 covers the side edges of the lower electrode layer 3 and the second electrode layer, an acoustic wave reflection structure is further arranged inside the substrate 1, and the acoustic wave reflection structure is used for limiting acoustic waves generated by piezoelectric resonance inside a resonance area.

Specifically, the acoustic wave reflecting structure is an air cavity 10/11 disposed inside the substrate 1, the effective resonance region of the device is located right above the air cavity 10/11, and the air cavity 10/11 is used to confine the acoustic wave generated by the piezoelectric resonance inside the resonance region.

Specifically, a FeGa/high-k material composite magnetic film layer 9 composed of a FeGa magnetic film layer 5 and a high-k material film layer 6 which are sequentially stacked is used as a repeating unit, the number n of the repeating units in the resonant type double-shaft magnetic sensor based on the FeGa/high-k material composite magnetic film is more than or equal to 1, wherein the FeGa magnetic film layer is provided with the FeGa magnetic film layer(110) Or (100) crystallographic preferred orientation, has delta E effect in both in-plane and out-of-plane directions of the FeGa magnetic thin film layer, the thickness of the FeGa magnetic thin film layer is 40-800nm, and the high-k material thin film layer 6 in the FeGa/high-k material composite magnetic thin film layer can be Al with high dielectric constant₂O₃Dielectric film of said Al₂O₃The thickness of the thin film layer is 5-100 nm.

Specifically, the seed layer 2 is an AlN seed crystal with a thickness of about 30-80nm, the lower electrode layer (i.e., the first electrode layer, the same below) 3 may be a Mo film with a thickness of 50-800nm and a shape of a regular pentagon, the piezoelectric layer 4 may be an AlN film with a thickness of 100-₂Or Si₃N₄The film is 50-500nm in thickness and is in a pentagonal ring shape, the insulating layer 7 covers the side edges of the upper electrode layer and the lower electrode layer, and the covering width is 2-5 microns.

Referring to fig. 11, in some more specific embodiments, a resonant dual-axis magnetic sensor based on a composite magnetic thin film of a FeGa/high-k material sequentially includes, from bottom to top: the acoustic wave resonator comprises a substrate 1, a seed crystal layer 2, a lower electrode layer (namely a first electrode layer) 3, a piezoelectric layer 4 and at least one FeGa/high-k value material composite magnetic film layer 9, wherein the FeGa/high-k value material composite magnetic film layer 9 comprises a FeGa magnetic film layer 5 and a high-k value material film layer 6 which are sequentially stacked, the FeGa magnetic film layer 5 located at the lowermost layer is stacked on the piezoelectric layer 4 and serves as a second electrode layer, the second electrode layer is further connected with a metal pad8, an insulating layer 7 is further arranged between the metal pad8 and the lower electrode layer 3, the insulating layer 7 covers the side edges of the lower electrode layer 3 and the second electrode layer, an acoustic wave reflection structure is further arranged on the surface of the substrate 1, and the acoustic wave reflection structure is used for limiting acoustic waves generated by piezoelectric resonance in a resonance area.

Specifically, the acoustic wave reflection structure includes a bragg reflection layer 12 disposed on the surface of the substrate 1, the seed layer 2 is stacked on the bragg reflection layer 12, the bragg reflection layer 12 includes a plurality of films (high impedance acoustic wave reflection films, low impedance acoustic wave reflection films) which are sequentially and alternately stacked in a high impedance and low impedance manner, and an effective resonance region of the device is located right above the bragg reflection layer 12.

Specifically, the FeGa/Al is composed of a FeGa magnetic film layer 5 and a high-k material film layer 6 which are sequentially stacked₂O₃The composite magnetic thin film layer 9 is used as a repeating unit, the number n of the repeating units in the resonant biaxial magnetic sensor based on the FeGa/high-k material composite magnetic thin film is more than or equal to 1, the FeGa magnetic thin film layer has (110) or (100) crystallographic preferred orientation, delta E effects are formed in the in-plane direction and the out-of-plane direction of the FeGa magnetic thin film layer, the thickness of the FeGa magnetic thin film layer is 40-800nm, the high-k material thin film layer 6 in the FeGa/high-k material composite magnetic thin film layer is a high-k material medium thin film with a high dielectric constant, and the thickness of the high-k material thin film layer is 5-100 nm.

Example 1:

based on FeGa/Al₂O₃The preparation method of the resonant biaxial magnetic sensor of the composite magnetic film comprises the following steps:

1) taking a Si (100) wafer with the thickness of 695 mu m as a substrate 1, sequentially forming a superposed AlN/Mo/AlN three-layer film on the substrate 1 by adopting a direct current sputtering process, wherein the thickness of the AlN/Mo/AlN three-layer film is respectively 30nm/200nm/1000nm, the AlN film directly arranged on the surface of the substrate 1 is used as a seed crystal layer 2, and a FeGa magnetic thin film layer 5 is formed on the AlN film by adopting a magnetron sputtering process, wherein the formed device structure is shown as a figure 2 (a);

2) processing the FeGa magnetic film layer 5 on the uppermost layer by adopting an IBE etching process, etching the AlN piezoelectric layer 4 by adopting ICP180 self-alignment, and etching the Mo film by adopting ICP380 to form the lower electrode layer 3, wherein the formed device structure is shown in figure 2 (b);

3) adopts a PECVD processDepositing SiO with thickness of 400nm on the side surface of the device₂The film is used as an insulating layer 7, the insulating layer 7 is covered on the side edges of the lower electrode layer 3 and the FeGa magnetic film layer 5, the insulating layer 7 can avoid the problem of short circuit of the upper electrode and the lower electrode when metal Pad connected with the upper electrode layer is led out, and the formed device structure is shown as a figure 2 (c);

4) adopting an FHR magnetron sputtering process to manufacture and form Ti/Au as metal Pad8, wherein the thicknesses of the metal Ti/Au are respectively 30nm and 150nm, and the structure of the formed device is shown as a figure 2 (d);

5) al with the thickness of 50nm is deposited and formed on the FeGa magnetic thin film layer 5 by adopting an ALD (atomic layer deposition) process₂O₃A film 6, and patterning is realized through an etching process, and the structure of the formed device is shown in fig. 2 (e);

6) mechanically thinning and CMP polishing the substrate 1, processing the thickness of the substrate 1 to 50-300 μm, and depositing SiO on the back of the substrate 1 by PECVD process₂The film is used as a hard mask for deep silicon etching, as shown in FIG. 2 (f);

7) an air cavity 10 is formed in the area of the back surface of the substrate 1 not covered by the mask by using STS HRM deep silicon etching process, and the shape of the air cavity 10 is pentagonal and has a depth of 50-300 μm, as shown in fig. 2 (g).

The structure of the biaxial magnetic sensor based on the film bulk acoustic resonator prepared in example 1 is shown in fig. 1, and comprises a substrate 1, a seed layer 2, a lower electrode layer 3, a piezoelectric layer 4, an upper electrode layer (FeGa magnetic thin film layer) 5, and Al from bottom to top in sequence₂O₃The back surface of the substrate 1, which is opposite to the seed crystal layer 2, is also provided with an air cavity 10, the upper electrode layer 5 is connected with the metal pad8, and an insulating layer 7 is covered between the metal pad8 and the lower electrode layer 3 as well as between the metal pad8 and the upper electrode layer 5.

Specifically, the FeGa magnetic thin film layer 5 sputtered in step (1) of this example showed a preferred orientation of (110) in powder XRD, as shown in fig. 3.

Specifically, the magnetic sensor prepared in the above embodiment 1 is subjected to sensing performance characterization, and a testing device used for performance characterization testing is shown in fig. 4 (fig. 4 is a vector network analyzer and a microwave probe station, a magnetic field control system controls the size of a magnetic field by changing current to provide an external bias magnetic field for a device, wherein the frequency band of the vector network analyzer is 10MHz to 120GHz, and the high-frequency magnetic sensor can be tested, and the probe distance satisfies the Pad distance between three finger electrodes of the sensor), an in-plane magnetic field in the forward and reverse directions is applied to the magnetic sensor, the resonant frequency and the return loss of the device change with the change of the magnetic field strength, and the resonant frequency and the return loss of the device change with the change of the magnetic field strength are shown in fig. 5; when a forward in-plane magnetic field is applied, the resonant frequency and the return loss of the device are reduced along with the increase of the magnetic field intensity, and the device presents a parabola shape, as shown in figure 6; applying a positive out-of-plane magnetic field to the magnetic sensor, the resonant frequency of the device decreases with decreasing magnetic field strength, then increases, and then decreases, as shown in FIG. 7; applying a positive out-of-plane magnetic field to the magnetic sensor, the return loss of the device decreases with increasing magnetic field strength, as shown in fig. 8; in-plane magnetic fields with different angles are applied to the magnetic sensor, the trend of the resonant frequency of the device changing along with the magnetic field intensity is approximately the same, the resolution of the magnetic fields with different angles is not reflected, namely the angles of the in-plane magnetic fields cannot be identified, as shown in fig. 9; when in-plane magnetic fields of different angles are applied to the magnetic sensor, the return loss of the device has approximately the same trend along with the change of the magnetic field strength, and the resolution of the magnetic fields of different angles is not reflected, that is, the angles of the in-plane magnetic fields cannot be identified, as shown in fig. 10.

Example 2

Example 2 of the invention provides a catalyst based on FeGa/Al₂O₃The preparation method of the resonant biaxial magnetic sensor of the composite magnetic film is substantially the same as that of the example 1, and only the positions of the air gaps (namely, air cavities) are different, so that the preparation steps of the example 2 only give out different processes, methods, parameters and the like from those of the example 1, the default is the same as that of the example 1, and the specific process of the example 2 different from that of the example 1 is as follows:

step 1) taking a Si (100) wafer with the thickness of about 695 mu m as a substrate, carrying out patterning treatment on the substrate through an MA6 photoetching machine, processing and forming a groove with the depth of 2 mu m on the substrate through an STS HRM deep silicon etching process, and depositing PSG (SiO doped with p element) with the thickness of 2.2 mu m through PECVD₂) In a CMP apparatusPolishing, wherein the roughness is in a nanometer level after polishing, then carrying out direct current sputtering on an AlN/Mo/AlN three-layer film on the processed substrate, wherein the thicknesses are respectively 30nm/200nm/1000nm, and then carrying out magnetron sputtering to obtain the FeGa magnetic film layer 5.

Steps 6) and 7), exposing the PSG layer pre-buried in the substrate by performing through hole etching on the substrate, and performing through hole etching on the substrate by using a BOE (7: 1) the solution etches and releases the PSG layer to form air gaps 11 in the substrate, and the device structure is shown in fig. 11.

Example 3

The FeGa/Al-based alloy provided in the embodiment₂O₃The preparation method of the resonant biaxial magnetic sensor of the composite magnetic film is substantially the same as that of embodiment 1, except that the air gap is removed and the bragg reflective layer 12 is added, so that the preparation steps of embodiment 3 only give out processes, methods, parameters and the like which are different from those in embodiment 1, that is, default is the same as that of embodiment 1, and the process of this embodiment which is different from that of embodiment 1 specifically is as follows:

taking a Si (100) wafer with the thickness of about 695 mu m as a substrate in the step 1), depositing 6 layers of high-low impedance alternating thin films on the substrate by magnetron sputtering and chemical vapor deposition to form a Bragg reflection layer 12, wherein the high-low impedance alternating thin films are W films/SiO films₂And then sequentially forming AlN/Mo/AlN three-layer films on the Bragg reflection layer 12 by adopting a direct current sputtering process, wherein the thicknesses of the three-layer films are respectively 30nm/200nm/1000nm, and then manufacturing the FeGa magnetic film layer 5 by adopting a magnetron sputtering process.

The manufacturing method in this embodiment does not need to perform steps 6) and 7) in embodiment 1), i.e., the preparation of the whole device is completed, and the structure of the formed device is as shown in fig. 12.

Example 4

One of the examples 4 is based on FeGa/Al₂O₃The structure and the manufacturing method of the resonant biaxial magnetic sensor of the composite magnetic film are basically the same as those of the devices in the embodiments 1 to 3, and the difference is that: the resonant biaxial magnetic sensor of this embodiment comprises a plurality of FeGa magnetic thin film layers 5 and Al stacked in this order₂O₃FeGa/Al composed of thin film layer 6₂O₃A composite magnetic thin film layer 9.

Example 5

One of the examples 5 is based on FeGa/HfO₂The structure and the manufacturing method of the resonant biaxial magnetic sensor of the composite magnetic thin film are basically the same as those of the device in the embodiment 1, and the difference is that: the resonant biaxial magnetic sensor in this embodiment employs HfO₂The film layer replaces Al₂O₃A thin film layer.

Example 6

The structure and the manufacturing method of the resonant biaxial magnetic sensor based on the FeGa/diamond composite magnetic thin film in the embodiment 6 are basically the same as those of the device in the embodiment 2, except that: in the resonant biaxial magnetic sensor of the present embodiment, a diamond thin film layer is used to replace Al₂O₃A thin film layer.

Example 7

One of the examples 7 is based on FeGa/ZrO₂The structure and the manufacturing method of the resonant biaxial magnetic sensor of the composite magnetic thin film are basically the same as those of the device in the embodiment 3, and the difference is that: the resonant biaxial magnetic sensor in this embodiment uses ZrO₂The film layer replaces Al₂O₃A thin film layer.

Comparative example 1

The structure and fabrication method of a FeGa-based resonant magnetic sensor in comparative example 1 are substantially the same as those in example 1, except that the FeGa magnetic thin film in comparative example 1 does not include a high-k dielectric layer (e.g., Al) thereon₂O₃) The performance test characterization of the sensor in comparative example 1 is performed, and the test result is shown in fig. 12 and 13, the variation amounts of frequency (35kHz) and S11 of the device in the applied magnetic field are much smaller than those of embodiment 1(1.03MHz), because the resonant frequency of the single FeGa thin film is lower, and after the high-k dielectric layer is added, the resonant frequency of the composite magnetic thin film layer is improved, which can satisfy the high-frequency response characteristic of the device, so that the variation amounts of frequency and S11 are larger, and the sensitivity of the sensor is higher.

It should be noted that the information shown in fig. 13 is obtained by further extracting values from fig. 12, and further analyzing the frequency and the deviation of S11, and the test method and the equipment used in comparative example 1 are the same as those in the examples.

The resonant biaxial magnetic sensor based on the FeGa/high-k material composite magnetic film provided by the embodiment of the invention realizes biaxial magnetic field strength detection by utilizing the in-plane and out-of-plane anisotropy of the delta E effect in the composite magnetic film layer, can have two reading modes of resonant frequency and return loss, and can effectively detect the in-plane and out-of-plane magnetic field strengths.

The resonant biaxial magnetic sensor based on the FeGa/high-k material composite magnetic film comprises a preferred orientation FeGa magnetic film, wherein the preferred orientation FeGa magnetic film has an anisotropic delta E effect and can realize magnetic field intensity sensing in two directions of the surface and the outside of the surface of a device; and, the resonant biaxial magnetic sensor based on the FeGa/high-k material composite magnetic thin film provided by the embodiment of the present invention is implemented based on a bulk acoustic wave resonator, so that the sensor itself has two readout modes of the resonant Frequency fr and the return loss S11, which can avoid the negative influence of the electrical noise on the magnetic field strength sensing, and the two readout modes of the resonant Frequency fr and the return loss S11 are shown in fig. 5, that is, the resonant Frequency and S11 of the device change with the change of the magnetic field strength, and the internal mechanism is the Δ E effect, that is, under the action of the magnetic field, the young modulus of the magnetic thin film changes with the change of the magnetic field strength, and for the thin film bulk acoustic wave resonator, the young modulus of the thin film changes, and the resonant Frequency and S11 of the device change.

In addition, according to the resonant biaxial magnetic sensor based on the FeGa/high-k material composite magnetic thin film provided by the embodiment of the invention, the high-k material thin film can improve the Δ E effect high-frequency response characteristic of the composite magnetic thin film, reduce the eddy current loss of the magnetic sensor, reduce the acoustic wave energy loss of the resonator, improve the sensitivity of the magnetic sensor, isolate air, and reduce the long-term oxidation of the FeGa magnetic thin film by the air environment.

It should be understood that the above-mentioned embodiments are merely illustrative of the technical concepts and features of the present invention, which are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and therefore, the protection scope of the present invention is not limited thereby. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.