Mechanical oscillator quantum device based on acoustic cavity and preparation method thereof and room temperature reading device

Abstract

The present application provides a mechanical oscillator quantum device based on an acoustic cavity, a preparation method thereof, and a room temperature reading device. The device includes: a thin film mechanical oscillator, including: a silicon substrate, including a silicon substrate body and an acoustic cavity, the silicon substrate body surrounding the acoustic cavity; a first thin film layer, arranged on the first surface of the silicon substrate body, and covering the acoustic cavity; a second thin film layer, arranged on the second surface of the silicon substrate body, and not covering the acoustic cavity; a first metallization layer, arranged on the first thin film layer, including a central portion arranged above the acoustic cavity, a main body portion arranged above the first surface of the silicon substrate body, and a connecting portion connecting the central portion and the main body portion; a bulk acoustic wave resonator, including: a sapphire substrate; a second metallization layer, arranged under the sapphire substrate; a piezoelectric layer, arranged under the second metallization layer, and connected to the first metallization layer through an indium column. The present application realizes efficient reading of the acoustic mode of a thin film mechanical oscillator through dissipative coupling in a room temperature vacuum environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor device preparation, and in particular, relates to a mechanical oscillator quantum device based on an acoustic cavity, a preparation method thereof, and a room temperature reading device. Background Art

[0002] Macro-scale mechanical oscillators, due to their extremely high quality factors, show great application potential in cutting-edge scientific and technological fields such as quantum precision measurement, sensing, information storage, and quantum interconnection. However, to fully utilize the effectiveness of these mechanical oscillators in the field of quantum information, the first condition is to achieve effective cooling of their ground state to significantly reduce the interference of thermal noise. Although semiconductor micro-nano technology has made significant progress in recent years, for low-frequency mechanical oscillators, achieving ground state cooling is still a technical problem that needs to be solved urgently.

[0003] The reading of traditional acoustic mode is mainly based on superconducting cavity. The material process is relatively complicated. In practical applications, superconducting materials need to have good stability and reliability to withstand complex electromagnetic environments and long-term operation. The degradation or performance changes that may occur in materials under extreme conditions pose a challenge to the reliability of superconducting cavities.

[0004] The current quantum acoustic technology mainly uses cryogenic technology and is tested in an extremely low temperature environment. In order to maintain the low temperature environment required for the superconducting cavity, an efficient refrigeration system is required. This not only includes the research and development and manufacturing of refrigeration equipment, but also involves how to effectively transfer the refrigeration capacity to various parts of the superconducting cavity to ensure that the entire cavity is uniformly and stably in a superconducting state. This not only increases the technical difficulty, but also brings high operating costs. The reading method of the acoustic mode of the thin film mechanical oscillator is mainly to use a superconducting microwave cavity in a low temperature environment. Although the superconducting microwave cavity has shown great application potential in many aspects of performance, its development still faces some technical challenges. For example, how to further improve the quality factor of the cavity, reduce the noise level, and increase the coherence time. At the same time, this technology is also mainly limited by the low temperature environment and its complex preparation process. Summary of the invention

[0005] In order to solve the above technical problems, the first aspect of the present application provides a mechanical oscillator quantum device based on an acoustic cavity, comprising:

[0006] Thin film mechanical oscillator, comprising:

[0007] A silicon substrate, comprising a silicon substrate body and an acoustic cavity, wherein the silicon substrate body surrounds the acoustic cavity;

[0008] A first film layer is disposed on the first surface of the silicon substrate body and covers the acoustic cavity;

[0009] a second film layer, disposed on a second surface of the silicon substrate body opposite to the first surface and not covering the acoustic cavity; and

[0010] a first metallization layer, disposed on the first film layer, comprising a central portion disposed above the acoustic cavity, a main body portion disposed above the first surface of the silicon substrate body, and a connecting portion connecting the central portion and the main body portion; and

[0011] Bulk acoustic wave resonator, comprising:

[0012] Sapphire substrate;

[0013] A second metallization layer is disposed under the sapphire substrate; and

[0014] A piezoelectric layer, disposed under the second metallization layer;

[0015] Wherein, the piezoelectric layer is connected to the first metallization layer through an indium column.

[0016] In some embodiments of the present application, the first metallization layer and the second metallization layer are respectively selected from one or more of molybdenum, gold and aluminum.

[0017] In some embodiments of the present application, the piezoelectric layer is selected from one or more of lithium niobate, zinc oxide and aluminum nitride.

[0018] In some embodiments of the present application, the first thin film layer and the second thin film layer are respectively selected from silicon nitride and / or silicon carbide.

[0019] In some embodiments of the present application, the thickness of the silicon substrate is 450~550μm, the thickness of the first thin film layer and the second thin film layer are respectively 40~60nm, the thickness of the first metallization layer is 15~25nm, the thickness of the sapphire substrate is 200~300μm, the thickness of the second metallization layer is 40~60nm, and the thickness of the piezoelectric layer is 0.5~1.5μm.

[0020] In some embodiments of the present application, when viewed in a direction perpendicular to the first metallization layer, the central portion is circular and the main body portion is triangular.

[0021] In some embodiments of the present application, the internal stress of the first thin film layer is greater than or equal to 1.2 GPa.

[0022] The second aspect of the present application provides a method for preparing a mechanical oscillator quantum device based on an acoustic cavity, comprising:

[0023] A thin film mechanical oscillator is prepared, comprising:

[0024] Growing a first thin film layer and a second thin film pre-layer on the first and second opposite surfaces of the silicon substrate, respectively;

[0025] Etching the second film prefabricated layer and the silicon substrate substrate to form a silicon substrate including an acoustic cavity and a silicon substrate body arranged around the acoustic cavity, and a second film layer arranged on the silicon substrate body, and making the first film layer suspended on the acoustic cavity;

[0026] growing a first metallization pre-layer on the first thin film layer; and

[0027] The first metallization prefabricated layer is subjected to spin coating, photolithography and development processing to form a first metallization layer including a central portion arranged above the acoustic cavity, a main body portion arranged above the silicon substrate main body and a connecting portion connecting the central portion and the main body portion; and

[0028] A bulk acoustic wave resonator is prepared, comprising:

[0029] growing a second metallization layer on the sapphire substrate; and

[0030] growing a piezoelectric layer on the second metallization layer;

[0031] The piezoelectric layer is connected to the first metallization layer.

[0032] In some embodiments of the present application, the piezoelectric layer and the first metallization layer are connected together by flip-chip bonding.

[0033] In some embodiments of the present application, the first thin film layer and the second thin film prefabricated layer are respectively grown on the first surface and the second surface of the silicon substrate by low pressure chemical vapor deposition;

[0034] Growing the first metallization prefabricated layer on the first thin film layer by electron beam evaporation or micro-nano processing sputtering;

[0035] growing a second metallization layer on the sapphire substrate by electron beam evaporation;

[0036] The piezoelectric layer is grown on the second metallization layer by metal organic compound chemical vapor deposition.

[0037] A third aspect of the present application provides a room temperature reading device, comprising any of the mechanical oscillator quantum devices described above or a mechanical oscillator quantum device manufactured by any of the preparation methods described above.

[0038] The present application uses the coupling effect of a bulk acoustic wave resonator and a mechanical vibrator in a room temperature vacuum environment to construct a unique acoustic cavity system, achieving efficient reading of the acoustic mode of a thin film mechanical vibrator. The present application can read the acoustic mode of a mechanical vibrator at room temperature through the dissipative coupling between the acoustic cavity and the mechanical vibrator.

[0039] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute improper limitations on the present disclosure.

[0041] Figure 1 It is a schematic diagram of the longitudinal cross-sectional structure of a mechanical oscillator quantum device based on an acoustic cavity provided in one embodiment of the present application.

[0042] Figure 2 yes Figure 1 A top view of a thin film mechanical oscillator of an acoustic cavity-based mechanical oscillator quantum device is shown.

[0043] Figure 3 The working principle of the coupling between the thin film mechanical oscillator and the acoustic cavity of the bulk acoustic wave resonator is shown.

[0044] Figure 4 It is a process flow chart for preparing a mechanical oscillator quantum device based on an acoustic cavity provided in one embodiment of the present application.

[0045] Figures 5 to 8 The process flow of preparing a thin film mechanical oscillator provided by an embodiment of the present application is shown.

[0046] Fig. 9 and Fig.10 The process flow of preparing a bulk acoustic wave resonator provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0047] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0048] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and installations of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or installations discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art may recognize the application of other processes and / or the use of other materials.

[0049] In the present invention, the terms "first", "second" and other ordinal numbers are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0050] For ease of description, spatially relative terms such as "under", "beneath", "lower", "below", "on", "above", "upper", "above", etc. may be used herein to describe the relationship of one element or feature to another (other) element or feature as shown in the drawings. It will be understood that the spatially relative terms are intended to cover different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawings is turned over, elements described as "under" or "below" or "below" other elements or features will then be oriented as "above" the other elements or features. Therefore, the exemplary terms "under" and "under" etc. can cover both above and below orientations.

[0051] It should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances. In addition, in the drawings, in order to effectively describe the technical content, the thickness, proportion and size of the components are exaggerated or reduced.

[0052] In addition, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. It will also be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and the present invention, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0053] As used herein, "about" or "approximately" is inclusive of the stated value and means within an acceptable range of deviation from the particular value as determined by one skilled in the art, taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0054] The following is a more detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings and examples, so that the scheme of the present invention and its advantages in various aspects can be better understood. However, the specific embodiments and examples described below are only for the purpose of illustration, rather than for limiting the present invention.

[0055] Figure 1 The figure shows a mechanical oscillator quantum device 100 based on an acoustic cavity provided by an embodiment of the present application. The mechanical oscillator quantum device 100 includes a thin film mechanical oscillator 10 and a bulk acoustic wave resonator 20 . Figure 2 It is a top view of the thin film mechanical oscillator 10 .

[0056] like Figure 1 As shown, the thin film mechanical oscillator 10 includes a silicon substrate 11 , a first thin film layer 12 , a second thin film layer 13 and a first metallization layer 14 .

[0057] The silicon substrate 11 includes a silicon substrate body 11 a and an acoustic cavity A, and the silicon substrate body 11 a surrounds the acoustic cavity A. Figure 1 The longitudinal cross-section of the acoustic cavity A shown is a trapezoidal structure that is small at the top and large at the bottom. In other embodiments of the present application, the longitudinal cross-section of the acoustic cavity A may also be other shapes. Figure 1 The cross section of the acoustic cavity A shown is circular. In other embodiments of the present application, the cross section of the acoustic cavity A may also be other shapes. Optionally, the thickness of the silicon substrate 11 is 450-550 μm, for example, about 450 μm, 460 μm, 470 μm, 480 μm, 490 μm, 500 μm, 510 μm, 520 μm, 530 μm, 540 μm or 550 μm.

[0058] The first film layer 12 is disposed on the first surface S1 of the silicon substrate body 11a and covers the acoustic cavity A. The first film layer 12 is a thin film oscillator layer to be read, which can be a thin film material of a specific frequency (for example, selected from silicon nitride and / or silicon carbide, etc.). Optionally, the thickness of the first film layer 12 is 40 to 60 nm, for example, about 40 nm, 42 nm, 44 nm, 46 nm, 48 nm, 50 nm, 52 nm, 54 nm, 56 nm, 58 nm or 60 nm. Optionally, the film internal stress of the layer is greater than or equal to 1.2 GPa.

[0059] The second film layer 13 is disposed on the second surface S2 of the silicon substrate body 11a opposite to the first surface S1 (i.e., the second film layer 13 is below the silicon substrate body 11a), and does not cover the acoustic cavity A. The thickness and material of the second film layer 13 may be consistent with those of the first film layer 12, and will not be described in detail herein.

[0060] The first metallization layer 14 is disposed on the first film layer 12. Figure 2 As shown, the first metallization layer 14 includes a central portion 14a disposed above the acoustic cavity A, a body portion 14b disposed above the first surface S1 of the silicon substrate body 11a, and a connecting portion 14c connecting the central portion 14a and the body portion 14b. Figure 2 In the embodiment shown (i.e., viewed in a direction perpendicular to the first metallization layer 14), the central portion 14a is circular, the main body portion 14b is triangular, and the main body portion 14b is only Figure 2 The first film layer 12 shown has a left side but not a right side. In other embodiments of the present application, the structure of the central portion 14a and the main body portion 14b may also be other, which can be set as needed. Optionally, the thickness of the first metallization layer is 15 to 25nm, for example, about 15nm, 16nm, 17nm, 18nm, 19nm, 20nm, 21nm, 22nm, 23nm, 24nm or 25nm. Optionally, the first metallization layer is selected from one or more of molybdenum, gold and aluminum.

[0061] like Figure 1 As shown, the BAW resonator 20 includes a sapphire substrate 21 , a second metallization layer 22 and a piezoelectric layer 23 .

[0062] The sapphire substrate 21 is used as the overall substrate of the bulk acoustic wave resonator 20. It adopts high-quality sapphire material. Sapphire has a high phase velocity and a high sound velocity, which means that the speed of sound waves propagating in sapphire is faster, which is beneficial to improving the performance of acoustic devices; sapphire also has good temperature stability. Sapphire has excellent temperature stability and can maintain stable performance in a wide temperature range, which is particularly important for acoustic devices that need to work in different temperature environments; sapphire also has low propagation loss. The loss of sound waves is low when propagating in sapphire, which helps to maintain the clarity and intensity of acoustic signals and improve the sensitivity and accuracy of acoustic devices. Optionally, the thickness of the sapphire substrate is 200~300μm, for example, about 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm, 270μm, 280μm, 290μm or 300μm.

[0063] The second metallization layer 22 is disposed on the sapphire substrate 21 (shown as the bottom in the figure). Optionally, the thickness of the second metallization layer is 40-60 nm, for example, about 40 nm, 42 nm, 44 nm, 46 nm, 48 nm, 50 nm, 52 nm, 54 nm, 56 nm, 58 nm or 60 nm. The material of the second metallization layer 22 can be consistent with the first metallization layer 14, which will not be repeated here.

[0064] The piezoelectric layer 23 is disposed on the second metallization layer 22 (shown as below in the figure). The piezoelectric layer 23 is connected to the first metallization layer 14 through the indium column 30, and the first metallization layer 14 and the piezoelectric layer 23 constitute an acoustic piezoelectric coupling cavity. The piezoelectric layer 23 has a significant piezoelectric effect, can convert mechanical stress into electrical energy, or convert electrical energy into mechanical vibration, and is widely used in sensors, transducers and micro-electromechanical systems. Optionally, the piezoelectric layer 23 is selected from one or more of lithium niobate, zinc oxide and aluminum nitride. Optionally, the thickness of the piezoelectric layer is 0.5~1.5μm, for example, about 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm or 1.5μm.

[0065] Figure 3 The working principle of the acoustic cavity coupling between the thin film mechanical vibrator 10 and the bulk acoustic wave resonator 20 is shown. a, b, and c in the figure are the vibration displacement of the thin film mechanical vibrator 10 (i.e., the change in the distance between the central portion 14a of the first metallization layer 14 and the piezoelectric layer 23), and the dotted line in the figure represents the vibration of the first thin film layer 12. Among them, b is the distance between the central portion 14a of the first metallization layer 14 and the piezoelectric layer 23 when not vibrating, and a and c are the distances between the central portion 14a and the piezoelectric layer 23 when vibrating upward and downward, respectively. Figure 3 The single arrow direction is the light path direction.

[0066] like Figure 3 As shown, in the high-overtone bulk acoustic wave resonator 20, the piezoelectric layer 23 will act as a phonon source for the acoustic cavity, providing multiple acoustic modes in the gigahertz (GHz) range, which enables them to couple well with the acoustic modes of the mechanical oscillator 10. The piezoelectric layer 23 emits phonon energy into the sapphire substrate 21, which acts as a phonon Fabry-Perot cavity that confines all phonon modes. The free spectral range between continuous high-overtone bulk acoustic wave modes is an inverse function of the thickness of the sapphire substrate 21. The interface between the second metallization layer 22 and the sapphire substrate 21 is critical for efficient power transfer from the phonon source (piezoelectric layer 23) to the phonon cavity (sapphire substrate 21).

[0067] like Figure 1 As shown, the first film layer 12 is a central suspended film. When it is excited by acoustic radiation pressure or optical radiation pressure of a certain threshold, the first film layer 12 will vibrate at an eigenfrequency.

[0068] like Figure 1 As shown, the bulk acoustic wave resonator 20 is welded upside down on the first metallization layer 14, and the distance between the piezoelectric layer 23 and the first metallization layer 14 can be controlled, and the height of the indium column 30 is adjusted according to different application requirements (sensors, quantum interface devices, quantum state ground state cooling, etc.). Under the condition of applying excitation, the first film layer 12 and the second film layer 13 will be affected by the shuttle electric field, be excited, and vibrate, thereby affecting the electric field shuttling between the electrode plates. At the same time, the piezoelectric layer 23 is affected by the electric field shuttling between the second metallization layer 22 and the first metallization layer 14, so that the piezoelectric layer 23 will produce frequency vibration, the vibration frequency range is GHz, and the generated frequency spacing is related to the thickness and material of the piezoelectric layer 23. Then, the frequency vibration generated by the piezoelectric layer 23 will be transmitted to the phonon cavity of the sapphire substrate 21, and the phonon mode will be bound by the phonon cavity. Finally, the received frequency signal is read out through the waveguide in the first film layer 12.

[0069] Figure 3 The reading devices D1 and D2 in the apparatus can perform IQ acquisition of a fixed duration through a spectrometer (real and imaginary parts of the time domain acquisition signal), and obtain the acoustic mode of the oscillator through Fourier transform. However, in order to obtain a more accurate bandwidth of the mechanical oscillator, an IQ ringing acquisition method can be used to fit a more accurate oscillator bandwidth. Among them, when the mechanical oscillator mode undergoes displacement vibration, the electric field energy will convert the electrical energy into the mechanical mode of the sapphire substrate 21 through the piezoelectric layer 23, and cause the mechanical mode frequency to move. The vibration displacement of the thin film oscillator changes as shown in Figure 3In the figure, the vibration displacements of a, b, and c can be used to obtain cavity modes of different depths based on the above principle. Therefore, when the pump excitation causes electromagnetically induced transparency at the frequency center of the acoustic cavity, the frequency of the mechanical oscillator can be read according to the detuning amount of the pump frequency. In this way, the mode reading and characterization of the mechanical oscillator is completed in a room temperature environment.

[0070] The present invention uses the coupling mode of the acoustic piezoelectricity of the thin film mechanical vibrator and the bulk acoustic wave resonator to read the acoustic mode of the thin film vibrator in a normal temperature environment. The bulk acoustic wave semiconductor chip has the advantages of high frequency, high quality factor, small size, integration and excellent performance parameters with extremely small size, which enables it to achieve high-performance resonant power in a limited space and maintain a stable resonant frequency in a wide temperature range.

[0071] This invention uses the coupling effect of a bulk acoustic wave resonator and a mechanical vibrator in a room temperature vacuum environment for the first time to construct a unique acoustic cavity system, achieving efficient reading of the acoustic mode of a thin film mechanical vibrator. This technology constitutes a new technical paradigm for reading thin film mechanical vibrators at room temperature based on the principle of acoustic piezoelectric coupling. This application can read the acoustic mode of a mechanical vibrator at room temperature through the dissipative coupling between the acoustic cavity and the mechanical vibrator.

[0072] Figure 4 A method for preparing a mechanical oscillator quantum device based on an acoustic cavity provided in an embodiment of the present application is shown, comprising the following steps S10 to S30.

[0073] S10: preparing a thin film mechanical oscillator.

[0074] Optionally, this step includes:

[0075] Growing a first thin film layer and a second thin film pre-layer on the first and second opposite surfaces of the silicon substrate, respectively;

[0076] Etching the second film prefabricated layer and the silicon substrate substrate to form a silicon substrate including an acoustic cavity and a silicon substrate body arranged around the acoustic cavity, and a second film layer arranged on the silicon substrate body, and making the first film layer suspended on the acoustic cavity;

[0077] growing a first metallization pre-layer on the first thin film layer; and

[0078] The first metallization prefabricated layer is subjected to spin coating, photolithography and development processes to form a first metallization layer including a central portion arranged above the acoustic cavity, a main body portion arranged above the silicon substrate body and a connecting portion connecting the central portion and the main body portion.

[0079] Optionally, the first thin film layer and the second thin film pre-layer are respectively grown on the first surface and the second surface of the silicon substrate by low pressure chemical vapor deposition (LPCVD).

[0080] Optionally, the first metallization pre-layer is grown on the first thin film layer by electron beam evaporation or micro-nano processing sputtering.

[0081] S20: preparing a bulk acoustic wave resonator.

[0082] Optionally, this step includes:

[0083] growing a second metallization layer on the sapphire substrate; and

[0084] A piezoelectric layer is grown on the second metallization layer.

[0085] Optionally, the second metallization layer is grown on the sapphire substrate by electron beam evaporation.

[0086] Optionally, the piezoelectric layer is grown on the second metallization layer by metal organic compound chemical vapor deposition.

[0087] S30: Connecting the piezoelectric layer of the bulk acoustic wave resonator and the first metallization layer of the thin film mechanical oscillator together.

[0088] Optionally, the piezoelectric layer is connected to the first metallization layer by flip-chip bonding, so that the thin film mechanical vibrator and the bulk acoustic wave resonator are combined together to form an acoustic piezoelectric coupling cavity.

[0089] Figures 5 to 7 FIG. 2 shows a process flow of preparing a thin film mechanical vibrator 10 provided in an embodiment of the present application. Figure 5 As shown, first, a first thin film layer 12 and a second thin film prefabricated layer 13A of silicon nitride with a thickness of about 50 nm are grown on the upper and lower surfaces of a silicon substrate 11A by LPCVD technology. Figure 6 As shown, the silicon of the silicon substrate base 11A is etched by etching technology, thereby forming a silicon substrate 11 including an acoustic cavity A and a silicon substrate body 11a arranged around the acoustic cavity A, and a second film layer 13 arranged on the silicon substrate body 11a, and the first film layer 12 is suspended on the acoustic cavity A. Then, as shown in FIG. Figure 7 As shown, the first metallization prefabricated layer 14A is grown on the first thin film layer 12 by electron beam evaporation. Figure 8As shown, the first metallization prefabricated layer is subjected to spin coating of photoresist S1813, baked at 150 degrees Celsius for 2 minutes, and laser direct writing of the prototype; developed with a developer, fixed with IPA, and then heated at 250 degrees Celsius (reflow process) to reshape the photoresist, thereby forming a first metallization layer 14 (such as Figure 2 as shown).

[0090] Figures 9 and 10 FIG. 2 shows a process flow for preparing a bulk acoustic wave resonator 20 provided in an embodiment of the present application. Fig. 9 As shown, first, a second metallization layer 22 is deposited on a sapphire substrate 21 by electron beam evaporation, with a thickness of about 50 nm. Fig.10 As shown, a piezoelectric layer 23 with a high piezoelectric coefficient of aluminum nitride with a thickness of about 1 μm is deposited on the second metallization layer 22 by MOCVD technology (Metal Organic Chemical Vapor Deposition Technology).

[0091] Finally, the piezoelectric layer 23 and the first metallization layer 14 are connected together by flip-chip bonding.

[0092] This application solves the problem of normal temperature testing: BAW resonators have excellent temperature stability, can maintain stable performance over a wide temperature range, and can complete stable normal temperature testing. Sound waves have low losses when propagating in sapphire, which helps maintain the clarity and strength of acoustic signals and improve the sensitivity and accuracy of acoustic devices.

[0093] This application also solves the problem of complex superconducting cavity material and process preparation: the piezoelectric phonon thin film device has a simple structure, few processes, and is easy to integrate. Its thin film mechanical vibrator reading device replaces the traditional electromagnetic wave circuit resonator with a bulk acoustic wave acoustic cavity, without fear of magnetic field compatibility issues. In addition, the micron-level piezoelectric film contains multiple resonance modes to avoid electromagnetic crosstalk.

[0094] Obviously, the above embodiments are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A mechanical oscillator quantum device based on an acoustic cavity, characterized in that: include: Thin film mechanical oscillator, comprising: A silicon substrate, comprising a silicon substrate body and an acoustic cavity, wherein the silicon substrate body surrounds the acoustic cavity; A first film layer is disposed on the first surface of the silicon substrate body and covers the acoustic cavity; a second film layer, disposed on a second surface of the silicon substrate body opposite to the first surface and not covering the acoustic cavity; and a first metallization layer, disposed on the first film layer, comprising a central portion disposed above the acoustic cavity, a main body portion disposed above the first surface of the silicon substrate body, and a connecting portion connecting the central portion and the main body portion; and Bulk acoustic wave resonator, comprising: Sapphire substrate; A second metallization layer is disposed under the sapphire substrate; and A piezoelectric layer, disposed under the second metallization layer; Wherein, the piezoelectric layer is connected to the first metallization layer through an indium column.

2. The mechanical oscillator quantum device according to claim 1, characterized in that: The first metallization layer and the second metallization layer are respectively selected from one or more of molybdenum, gold and aluminum.

3. The mechanical oscillator quantum device according to claim 1, characterized in that: The piezoelectric layer is selected from one or more of lithium niobate, zinc oxide and aluminum nitride.

4. The mechanical oscillator quantum device according to claim 1, characterized in that: The first thin film layer and the second thin film layer are respectively selected from silicon nitride and / or silicon carbide.

5. The mechanical oscillator quantum device according to claim 1, characterized in that: The thickness of the silicon substrate is 450~550μm, the thickness of the first thin film layer and the second thin film layer are 40~60nm respectively, the thickness of the first metallization layer is 15~25nm, the thickness of the sapphire substrate is 200~300μm, the thickness of the second metallization layer is 40~60nm, and the thickness of the piezoelectric layer is 0.5~1.5μm.

6. The mechanical oscillator quantum device according to claim 1, characterized in that: When viewed in a direction perpendicular to the first metallization layer, the central portion is circular and the main body portion is triangular; The internal stress of the first thin film layer is greater than or equal to 1.2 GPa.

7. A method for preparing a mechanical oscillator quantum device based on an acoustic cavity, characterized in that: include: A thin film mechanical oscillator is prepared, comprising: Growing a first thin film layer and a second thin film pre-layer on the first and second opposite surfaces of the silicon substrate, respectively; Etching the second film prefabricated layer and the silicon substrate substrate to form a silicon substrate including an acoustic cavity and a silicon substrate body arranged around the acoustic cavity, and a second film layer arranged on the silicon substrate body, and making the first film layer suspended on the acoustic cavity; growing a first metallization pre-layer on the first thin film layer; and The first metallization prefabricated layer is subjected to spin coating, photolithography and development processing to form a first metallization layer including a central portion arranged above the acoustic cavity, a main body portion arranged above the silicon substrate main body and a connecting portion connecting the central portion and the main body portion; and A bulk acoustic wave resonator is prepared, comprising: growing a second metallization layer on the sapphire substrate; and growing a piezoelectric layer on the second metallization layer; and The piezoelectric layer is connected to the first metallization layer.

8. The preparation method according to claim 7, characterized in that: The piezoelectric layer and the first metallization layer are connected together by flip-chip bonding.

9. The preparation method according to claim 7, characterized in that: Growing the first thin film layer and the second thin film prefabricated layer on the first surface and the second surface of the silicon substrate respectively by low pressure chemical vapor deposition; Growing the first metallization prefabricated layer on the first thin film layer by electron beam evaporation or micro-nano processing sputtering; growing a second metallization layer on the sapphire substrate by electron beam evaporation; The piezoelectric layer is grown on the second metallization layer by metal organic compound chemical vapor deposition.

10. A room temperature reading device, characterized in that: The invention comprises the mechanical oscillator quantum device described in any one of claims 1 to 6 or the mechanical oscillator quantum device prepared by the preparation method described in any one of claims 7 to 9.

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