A novel chip structure of surface acoustic wave or shear wave excited bulk acoustic wave microwave device

Abstract

The present invention discloses a novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure, the chip structure comprises: a surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip circuit and a chip substrate, a first groove and a second groove are arranged on the chip substrate, the first groove is filled with a first piezoelectric material, a first electrode is arranged on the first piezoelectric material, one end of the first electrode is connected to the first piezoelectric material, and the other end is connected to the signal input end of the chip circuit; the second groove is filled with a second piezoelectric material, a second electrode is arranged on the second piezoelectric material, one end of the second electrode is connected to the second piezoelectric material, and the other end is connected to the signal output end of the chip circuit. The novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure provided by the present invention reduces the transmission loss and microwave insertion loss of the device, and improves the performance of the device such as frequency and quality factor.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave communication equipment, and in particular to a novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure. Background Art

[0002] Surface acoustic wave (SAW) and bulk acoustic wave devices (FBAR) play a vital role in various communication devices, systems, and terminals. Their technical indicators and characteristics are the key to the performance of communication equipment. If the acoustic wave transmission loss of the material can be significantly reduced, the anti-interference ability and power consumption of the communication equipment will be greatly improved. Without changing the design of existing surface acoustic wave and bulk acoustic wave devices, it is crucial for modern communication equipment to achieve a significant reduction in transmission loss through the application of new materials. With the increasingly tight spectrum resources today, the demand for technologies such as miniaturization, high integration, low power consumption, and low heat generation is becoming more and more urgent. Various new materials are used in surface acoustic wave and bulk acoustic wave devices, especially diamond materials, which are increasingly valued.

[0003] The longitudinal wave speed of diamond material is as high as 18000m / s, the highest among existing natural and synthetic materials, 3-10 times higher than ordinary piezoelectric materials. The surface acoustic wave and bulk acoustic wave devices prepared have extremely high quality factors (Q values). Surface acoustic wave and bulk acoustic wave microwave devices have been used in various high-frequency and high-power communication equipment, systems and terminals, such as delay lines, resonators, filters, acousto-optic modulators, and acousto-optic switches. However, most surface acoustic wave and bulk acoustic wave devices use ordinary piezoelectric materials as the transmission matrix, which has serious sound transmission losses and the response frequency is restricted by the low sound propagation speed of piezoelectric materials. The development of surface acoustic wave and bulk acoustic wave devices using diamond materials can further improve the anti-interference ability of communication equipment, reduce power consumption, and increase the response frequency, thereby improving the overall performance of communication equipment.

[0004] Traditional surface acoustic wave and bulk acoustic wave devices are mainly composed of piezoelectric film and electrodes, among which the electrodes are formed by thin film deposition, photolithography and etching on the piezoelectric film through traditional integrated circuit technology. The signal is input into one electrode, and the microwave signal is converted into an acoustic wave signal by the piezoelectric material and transmitted in the piezoelectric film. Then, the acoustic wave signal is converted into a microwave signal for output at the other electrode through the inverse piezoelectric effect. Through appropriate piezoelectric film and electrode design, acoustic wave signals that meet specific frequency requirements can pass through to achieve resonance and filtering functions. Although traditional surface acoustic wave and bulk acoustic wave devices can also achieve microwave filtering functions, they have the following shortcomings that need to be overcome:

[0005] 1. Conventional piezoelectric materials have large acoustic wave losses, and the sensitivity and anti-interference ability of surface acoustic wave and bulk acoustic wave devices made of them are significantly reduced.

[0006] 2. In the diamond / piezoelectric / electrode multilayer structure using diamond material, the acoustic wave signal is still mainly propagated in the piezoelectric layer, the acoustic wave transmission loss is still large, and the role of the diamond material is not effectively played. Summary of the invention

[0007] In view of the deficiencies of the above-mentioned technologies, the purpose of the present invention is to provide a new surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure to reduce transmission loss and microwave insertion loss and improve the device's frequency and quality factor and other performance.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] A novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure, the chip structure comprising: a surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip circuit and a chip substrate;

[0010] The chip substrate is provided with a first groove and a second groove, the first groove is filled with a first piezoelectric material, a first electrode is provided on the first piezoelectric material, one end of the first electrode is connected to the first piezoelectric material, and the other end of the first electrode is connected to the signal input end of the chip circuit;

[0011] The second groove is filled with a second piezoelectric material, a second electrode is disposed on the second piezoelectric material, one end of the second electrode is connected to the second piezoelectric material, and the other end of the second electrode is connected to the signal output end of the chip circuit.

[0012] Optionally, the chip substrate material is a diamond material or a silicon material with a diamond film deposited thereon.

[0013] Optionally, the first groove and the second groove each contain a plurality of grooves.

[0014] Optionally, the distances between the grooves are the same or different.

[0015] Optionally, the shape, size and / or depth of the groove can be varied.

[0016] Optionally, the shape and / or size of the first electrode and the second electrode can be adjusted.

[0017] Optionally, both the first electrode and the second electrode are made of conductive metal.

[0018] Optionally, a substrate is provided under the chip base for supporting the chip structure.

[0019] Optionally, the first electrode is an input electrode and is packaged by spot welding leads, and the second electrode is an output electrode and is packaged by spot welding leads.

[0020] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0021] The present invention proposes a novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure, the chip structure comprises: a surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip circuit and a chip substrate, a first groove and a second groove are arranged on the chip substrate, the first groove is filled with a first piezoelectric material, a first electrode is arranged on the first piezoelectric material, one end of the first electrode is connected to the first piezoelectric material, and the other end is connected to the signal input end of the chip circuit; the second groove is filled with a second piezoelectric material, a second electrode is arranged on the second piezoelectric material, one end of the second electrode is connected to the second piezoelectric material, and the other end is connected to the signal output end of the chip circuit. The present invention adopts a diamond material with a groove structure as the main sound wave transmission medium, maximizes the highest sound propagation speed and minimum sound loss performance of diamond, reduces the transmission loss and microwave insertion loss of the device, and improves the frequency and quality factor and other performances of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 A schematic cross-sectional view of a novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure according to an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of the microwave device principle in an embodiment of the present invention;

[0025] Figure 3 It is a performance curve diagram of the microwave device in the embodiment of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The purpose of the present invention is to provide a novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure, which reduces the transmission loss and microwave insertion loss of the device and improves the performance of the device such as frequency and quality factor.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] like Figure 1 As shown, a cross-sectional schematic diagram of a novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure, the chip structure includes: a surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip circuit and a chip substrate 101, the chip substrate 101 is provided with a first groove 102 and a second groove 103, the first groove 102 is filled with a first piezoelectric material 104, a first electrode 106 is provided on the first piezoelectric material 104, one end of the first electrode 106 is connected to the first piezoelectric material 104, and the other end of the first electrode 106 is connected to the signal input end of the chip circuit; the second groove 103 is filled with a second piezoelectric material 105, a second electrode 107 is provided on the second piezoelectric material 105, one end of the second electrode 107 is connected to the second piezoelectric material 105, and the other end of the second electrode 107 is connected to the signal output end of the chip circuit.

[0030] In this embodiment, the chip substrate 101 material is a single substrate material composed of diamond material or silicon material deposited with diamond film to form surface acoustic wave and bulk acoustic wave devices. The chip substrate 101 material is not limited to the above two types, and can also be other materials deposited with diamond film, so that the diamond material is used as the main sound wave transmission medium, which reduces the transmission loss of the device and the microwave insertion loss, and improves the frequency and quality factor and other performance of the device.

[0031] In this embodiment, the first groove 102 and the second groove 103 both contain a plurality of grooves, each of the grooves is filled with a piezoelectric material, and corresponding electrodes are arranged on the piezoelectric material.

[0032] As an optional implementation, the distances between the grooves are the same or different, the shape, size and / or depth of the grooves can be changed, and the shape and / or size of the first electrode 106 and the second electrode 107 can be adjusted. By adjusting one or more of the above, the device can respond to microwave spectra of different frequencies, bandwidths, etc., and various functions of the microwave device can be realized.

[0033] As an optional implementation, both the first electrode 106 and the second electrode 107 are made of conductive metal.

[0034] As an optional implementation, a substrate is disposed under the chip base 101 for supporting the chip structure.

[0035] As an optional embodiment, the first electrode 106 is an input electrode and is packaged by spot welding leads. The second electrode 107 is an output electrode and is packaged by spot welding leads. The packaging of the input and output electrodes is not limited to spot welding leads. Microwave input and output electrodes can also be led out by other methods to make various microwave devices.

[0036] The novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure provided in this embodiment can realize the functions of conventional surface acoustic wave and bulk acoustic wave devices, meet the requirements of microwave-acoustic wave conversion and microwave signal selection, and also achieve high sensitivity and low loss. Various groove shapes, piezoelectric materials and electrode materials can be designed according to needs, and the design can be modified according to needs. It has the characteristics of excellent technical indicators, flexibility and scalability, and easy use. The process corresponding to this structure is compatible with large-scale integrated circuits, can realize mass production, is compatible with existing devices, and can be applied to a variety of communication equipment.

[0037] In this embodiment, diamond material is used as the matrix, and the diamond material with excellent acoustic wave transmission characteristics is used as the main transmission medium of surface acoustic wave and bulk acoustic wave devices, which greatly reduces transmission loss and improves device performance. This structure can be prepared using standard processes for large-scale integrated circuits and can be mass-produced on a large scale.

[0038] The functions of the components and the corresponding processes of this embodiment are described as follows:

[0039] 1. Diamond material: Diamond material uses single crystal or polycrystalline high-purity diamond flakes or films, and the length, width and height dimensions can be customized. The typical dimensions are 3*3*0.3mm (flake, self-supporting) or 0.03mm (film, with other materials as the matrix), the impurity N content is PPB level, and the upper and lower surface roughness Ra<10nm. It provides the best sound wave propagation medium for surface acoustic wave or bulk acoustic wave microwave devices.

[0040] 2. Groove structure: In this embodiment, a conventional surface acoustic wave interdigital electrode shape is adopted. The interdigital grooves are completed by photolithography and dry etching using conventional semiconductor processes. The groove depth is about 5 microns and the groove cross-section is an inverted trapezoid.

[0041] 3. Piezoelectric material: In this embodiment, ALN is selected as the piezoelectric material, and other piezoelectric materials can also be deposited. The piezoelectric material is preferably a film thickness that completely fills the grooves and the diamond surface. Through physical vapor deposition, chemical vapor deposition, electroplating or other growth methods, the growth thickness and growth quality of the piezoelectric film can be stably controlled. After the growth is completed, the piezoelectric material deposited on the non-grooved part of the diamond surface is polished away by chemical mechanical polishing (CMP) using conventional semiconductor processes, so that the basic circuit is formed through the grooves.

[0042] 4. Circuit formation and packaging: In this embodiment, Al-Cu is selected as the electrode, and other electrode materials can also be deposited. The electrode thickness is based on the design, generally about 2 microns. Through physical vapor deposition, electroplating or other growth methods, the growth thickness and growth quality of the electrode film can be stably controlled. After the growth is completed, the traditional semiconductor process is used through photolithography and dry etching to retain only the electrode on the piezoelectric material, thereby forming the electrode. The specific circuit can be defined according to the actual device mode and frequency, and the input and output electrodes can be led out by spot welding, packaging or other methods.

[0043] By adjusting the material composition of the piezoelectric / electrode, the shape and size of the groove and the groove depth, and the shape and size of the electrode, surface acoustic wave and bulk acoustic wave devices with different modes and frequencies can be formed.

[0044] 5. Microwave device performance curve

[0045] The surface acoustic wave and bulk acoustic wave devices in this embodiment are simulated and tested using common microwave design and simulation software and microwave testing instruments. Figure 3 is a performance curve diagram of the microwave device in the embodiment, such as Figure 3 As shown, the center frequency is 1.75 GHz and the bandwidth is 0.05 GHz.

[0046] The positive "n"-shaped curve shows the S21 (transmission coefficient) of the filter, which is the voltage ratio of microwaves transmitted from the input end to the output end. It is close to 0dB near the middle 1.75GHz (logarithmic mode, the ratio is 1), indicating that microwave signals can pass through completely. The S21 of microwave signals below or above the passband frequency drops significantly to -50dB and below, which is obviously suppressed, indicating that microwave signals cannot pass through.

[0047] The inverted "n" curve shows the S11 (self-reflection coefficient) of the filter. There are many fluctuations in the passband. The voltage ratio of the microwave reflected from the input end to the input end has a maximum value of less than -10dB in the passband, indicating that almost no signal is reflected to the input end in the passband; the S11 of the microwave signal below or above the passband frequency is 0 (logarithmic mode, the ratio is 1), indicating that all the signals are reflected back to the input end.

[0048] The principle of the microwave device in this embodiment is:

[0049] Figure 2 Schematic diagram of the microwave device principle of the embodiment of the present invention. Figure 2As shown, the microwave signal is transmitted to the piezoelectric material under the electrode through the input IDT (input piezoelectric / electrode circuit) 201, and the surface acoustic wave (SAW) of the corresponding frequency is excited through the inverse piezoelectric effect. A certain groove width and the width between each groove correspond to the corresponding resonant frequency. Resonance can be formed between the electrodes corresponding to several pairs of grooves of the same width. The input IDT (input piezoelectric / electrode circuit) 201 generates a fixed frequency surface acoustic wave, which is transmitted to the output IDT (output piezoelectric / electrode circuit) 202 through the diamond material. Through the piezoelectric effect, only the sound wave of this frequency can achieve resonance and excite the electromagnetic wave of the corresponding frequency, and the electromagnetic wave is output through the output IDT (output piezoelectric / electrode circuit) 202, thereby realizing microwave filtering.

[0050] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure, characterized in that: The chip structure comprises: a surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip circuit and a chip substrate; The chip substrate is provided with a first groove and a second groove, the first groove is filled with a first piezoelectric material, a first electrode is provided on the first piezoelectric material, one end of the first electrode is connected to the first piezoelectric material, and the other end of the first electrode is connected to the signal input end of the chip circuit; The second groove is filled with a second piezoelectric material, a second electrode is disposed on the second piezoelectric material, one end of the second electrode is connected to the second piezoelectric material, and the other end of the second electrode is connected to the signal output end of the chip circuit; By adjusting the material composition of the piezoelectric / electrode, the shape and size of the groove and the depth of the groove, and the shape and size of the electrode, surface acoustic wave and bulk acoustic wave devices of different modes and frequencies can be formed; The chip substrate material is a diamond material or a silicon material deposited with a diamond film; the diamond material is a single crystal or polycrystalline high-purity diamond plate or film; The first groove and the second groove each contain a plurality of grooves; The distances between the grooves are the same or different; By using diamond material with groove structure as the sound wave transmission medium, the highest sound propagation speed and minimum sound loss performance of diamond are maximized, the transmission loss and microwave insertion loss of the device are reduced, and the frequency and quality factor of the device are improved; The thickness of the piezoelectric material film completely fills the grooves and the diamond surface; the growth thickness and growth quality of the piezoelectric film can be stably controlled through physical vapor deposition, chemical vapor deposition, and electroplating; after the growth is completed, the piezoelectric material deposited on the non-grooved parts of the diamond surface is polished by chemical mechanical polishing using traditional semiconductor processes, thereby forming a circuit through the grooves; The microwave signal is transmitted to the piezoelectric material under the electrode through the input IDT, and the surface acoustic wave of the corresponding frequency is excited through the inverse piezoelectric effect. A certain groove width and the width between each groove correspond to the corresponding resonant frequency. Resonance is formed between the electrodes corresponding to several pairs of grooves of the same width. The input IDT generates a fixed-frequency surface acoustic wave, which is transmitted to the output IDT through the diamond material. Through the piezoelectric effect, only the sound wave of this frequency can resonate and excite the electromagnetic wave of the corresponding frequency, and this electromagnetic wave is output through the output IDT, thereby realizing microwave filtering.

2. The novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure according to claim 1 is characterized in that: The shape, size and / or depth of the grooves can vary.

3. The novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure according to claim 1 is characterized in that: The shapes and / or sizes of the first electrode and the second electrode can be adjusted.

4. The novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure according to claim 1 is characterized in that: The first electrode and the second electrode are both made of conductive metal.

5. The novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure according to claim 1 is characterized in that: A substrate is arranged under the chip base for supporting the chip structure.

6. The novel surface acoustic wave or shear wave excited bulk acoustic wave microwave device chip structure according to claim 1 is characterized in that: The first electrode is an input electrode and is packaged by spot welding leads, and the second electrode is an output electrode and is packaged by spot welding leads.

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