Surface acoustic wave (SAW) device
By employing a multi-layered IDT electrode layer in the SAW device, and using specific materials and heat treatment techniques, the problem of device failure under high temperature and high power was solved, achieving higher heat resistance and durability, and extending the service life of the device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TIANJIN WISOL ELECTRONICS CO LTD
- Filing Date
- 2025-10-20
- Publication Date
- 2026-04-21
AI Technical Summary
Existing surface acoustic wave (SAW) devices are prone to failure under high temperature and high power conditions, and lack sufficient heat resistance and durability.
The IDT electrode layer adopts a multi-layer structure, including an adhesive layer, an electrode diffusion layer, an alloy forming layer, a main electrode layer, and a connecting layer. It uses alloys of materials such as copper, magnesium, silver, and aluminum, and forms alloy layers through heat treatment to enhance the strength and durability of the electrode and meet specific thickness ratio requirements.
It significantly improves the heat resistance and power durability of SAW devices, extending their service life.
Smart Images
Figure CN121907183A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a surface acoustic wave (SAW) device. Background Technology
[0002] A surface acoustic wave (SAW) device is configured to generate acoustic waves that propagate along the surface of an elastic substrate. As a result of the piezoelectric effect, these acoustic waves are generated by an electrical signal, and when the electric field of the acoustic waves is concentrated near the surface of the substrate, they can interact with the conduction electrons of another semiconductor disposed directly above the surface. The medium through which the acoustic waves propagate is a piezoelectric material with a high electromechanical coupling coefficient and low acoustic energy loss, and the semiconductor has high conduction electron mobility and optimal resistivity, with low DC power requirements to ensure optimal efficiency. The SAW device serves as an electromechanical component that replaces electronic circuitry by utilizing the interaction between surface acoustic waves and the conduction electrons of the semiconductor.
[0003] These SAW devices are used not only in various communication applications but also as key components in mobile phones and base stations. The most commonly used types of SAW devices are passband filters and resonators. Due to their low cost, small size, and superior technical parameters (such as low loss and selectivity), SAW devices have a significant competitive advantage over devices based on other physical principles.
[0004] In particular, recent applications of SAW devices require high filtering performance and low insertion loss, and therefore, various attempts have been made to reduce insertion loss. However, conventional methods for reducing insertion loss involve techniques such as adjusting the spacing between electrodes or using multiple SAW devices.
[0005] However, in the case of these SAW devices, multiple electrode layers forming the IDT electrode failed within approximately 1100 hours at a temperature of 125°C and a power of 29 dBm, indicating their susceptibility to high temperature and high power durability. Summary of the Invention
[0006] This disclosure provides a surface acoustic wave (SAW) device with high heat resistance and high power durability.
[0007] In one aspect of this disclosure, a surface acoustic wave (SAW) device includes a piezoelectric substrate and an IDT electrode layer formed on the piezoelectric substrate. The IDT electrode layer includes: an adhesive layer for bonding to the piezoelectric substrate; a first electrode diffusion layer formed on the adhesive layer; a first alloy forming layer formed on the first electrode diffusion layer; a main electrode layer formed on the first alloy forming layer; a second alloy forming layer formed on the main electrode layer; a second electrode diffusion layer formed on the second alloy forming layer; and a connecting layer formed on the second electrode diffusion layer.
[0008] Each of the first electrode diffusion layer and the second electrode diffusion layer can be formed from any one of copper (Cu), magnesium (Mg), and silver (Ag) or an alloy thereof.
[0009] The main electrode layer can be formed from any of the following materials: copper (Cu), aluminum (Al), and platinum (Pt) or their alloys.
[0010] Each of the first alloy forming layer and the second alloy forming layer may be formed from an alloy including at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
[0011] Each of the first electrode diffusion layer, the second electrode diffusion layer, and the main electrode layer can have an average thickness that satisfies the following equation:
[0012] 0.05≤(Td1+Td2) / Tm≤0.18
[0013] Where Td1 represents the average thickness of the first electrode diffusion layer, Td2 represents the average thickness of the second electrode diffusion layer, and Tm represents the average thickness of the main electrode layer.
[0014] On the other hand, the surface acoustic wave (SAW) device includes a piezoelectric substrate and an IDT electrode layer formed on the piezoelectric substrate. The IDT electrode layer includes: an adhesive layer for bonding with the piezoelectric substrate; an electrode diffusion layer formed on the adhesive layer; an alloy forming layer formed on the electrode diffusion layer; a first main electrode layer formed on the alloy forming layer; an electrode diffusion suppression layer formed on the first main electrode layer; a second main electrode layer formed on the electrode diffusion suppression layer; and a connecting layer formed on the second main electrode layer.
[0015] The electrode diffusion layer can be formed from any of the materials, such as copper (Cu), magnesium (Mg), and silver (Ag), or their alloys.
[0016] Each of the first and second main electrode layers can be formed from any one of copper (Cu), aluminum (Al), and platinum (Pt) or an alloy thereof.
[0017] The alloy forming layer can be formed from an alloy including at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
[0018] The electrode diffusion suppression layer can be formed from any of the following materials or alloys: chromium (Cr), titanium (Ti), nickel (Ni), zirconium (Zr), and titanium nitride (TiN).
[0019] Each of the first main electrode layer, the second main electrode layer, and the electrode diffusion suppression layer can have an average thickness that satisfies the following equation:
[0020] 0.04≤(Tb) / (Tm1+Tm2)≤0.15
[0021] Where Tm1 represents the average thickness of the first main electrode layer, Tm2 represents the average thickness of the second main electrode layer, and Tb represents the average thickness of the electrode diffusion suppression layer.
[0022] In another aspect, the surface acoustic wave (SAW) device includes a piezoelectric substrate and an IDT electrode layer formed on the piezoelectric substrate. The IDT electrode layer includes: an adhesive layer for bonding with the piezoelectric substrate; a first electrode diffusion layer formed on the adhesive layer; a first alloy forming layer formed on the first electrode diffusion layer; a first main electrode layer formed on the first alloy forming layer; an electrode diffusion suppression layer formed on the first main electrode layer; a second main electrode layer formed on the electrode diffusion suppression layer; a second alloy forming layer formed on the second main electrode layer; a second electrode diffusion layer formed on the second alloy forming layer; and a connecting layer formed on the second electrode diffusion layer.
[0023] Each of the first electrode diffusion layer and the second electrode diffusion layer can be formed from any one of copper (Cu), magnesium (Mg), and silver (Ag) or an alloy thereof.
[0024] Each of the first and second main electrode layers can be formed from any one of copper (Cu), aluminum (Al), and platinum (Pt) or an alloy thereof.
[0025] Each of the first alloy forming layer and the second alloy forming layer may be formed from an alloy including at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
[0026] The electrode diffusion suppression layer can be formed from any of the following materials or alloys: chromium (Cr), titanium (Ti), nickel (Ni), zirconium (Zr), and titanium nitride (TiN).
[0027] Each of the first main electrode layer, the second main electrode layer, and the electrode diffusion suppression layer can have an average thickness that satisfies the following equation:
[0028] 0.04≤(Tb) / (Tm1+Tm2)≤0.15
[0029] Where Tm1 represents the average thickness of the first main electrode layer, Tm2 represents the average thickness of the second main electrode layer, and Tb represents the average thickness of the electrode diffusion suppression layer. Attached Figure Description
[0030] Figure 1 The structure of a SAW device according to a first embodiment of the present disclosure is shown.
[0031] Figure 2 This is a reference diagram showing the formation of a first alloy layer by applying heat to the contact surface between the first electrode diffusion layer and the main electrode layer.
[0032] Figure 3 This is a comparison of the lifespan of a SAW device according to the first embodiment of this disclosure with that of conventional technology.
[0033] Figure 4 The structure of a SAW device according to a second embodiment of the present disclosure is shown.
[0034] Figure 5 This is a comparison of the lifespan of a SAW device according to a second embodiment of this disclosure with that of conventional technology.
[0035] Figure 6 The structure of a SAW device according to a third embodiment of the present disclosure is shown. Detailed Implementation
[0036] The terminology used herein is for descriptive purposes only and is not intended to limit this disclosure. In this specification, the singular forms are intended to include the plural forms unless the context clearly indicates otherwise.
[0037] In this specification, the terms "include" and "comprise" and variations thereof are intended to specify the presence of the stated feature, integral, step, operation, element, or component, but do not preclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, or combinations thereof. Furthermore, embodiments described herein will be illustrated with reference to cross-sectional and / or plan views as illustrative examples of this disclosure. Therefore, embodiments of this disclosure are not limited to the specific forms shown, but also include various modifications and variations. Consequently, the areas shown in the drawings are schematic in nature, and the shapes of the shown areas are intended to describe the specific form of the area of the device and are not intended to limit the scope of this disclosure.
[0038] Figure 1 The structure of a surface acoustic wave (SAW) device according to a first embodiment of the present disclosure is shown.
[0039] The piezoelectric substrate 100A can be formed of a material capable of providing a piezoelectric effect. For example, the piezoelectric substrate 100A can be one of a silicon substrate, a diamond substrate, a sapphire substrate, a silicon carbide substrate, a LiNbO3 substrate, and a LiTaO3 substrate.
[0040] An IDT electrode layer 200A is formed on a piezoelectric substrate 100A. The IDT electrode layer 200A has multiple electrode layers that are arranged alternately at equal intervals along the horizontal direction.
[0041] like Figure 1As shown, the IDT electrode layer 200A includes an adhesive layer 210A, a first electrode diffusion layer 220A-1, a first alloy forming layer 230A-1, a main electrode layer 240A, a second alloy forming layer 230A-2, a second electrode diffusion layer 220A-2, and a connecting layer 250A.
[0042] The adhesive layer 210A is used to bond the various layers of the IDT electrode layer 200A to the piezoelectric substrate 100A. The adhesive layer 210A is formed on the piezoelectric substrate 100A.
[0043] The adhesive layer 210A may be formed from at least one material selected from titanium, aluminum oxide (Al2O3), titanium nitride (TiN), chromium (Cr), zirconium (Zr), hafnium oxide (HfO2), titanium oxide (TiO2), and tantalum pentoxide (Ta2O5).
[0044] The first electrode diffusion layer 220A-1 is formed on the adhesive layer 210A and disposed below the main electrode layer 240A to enhance the strength of the main electrode layer 240A.
[0045] The first electrode diffusion layer 220A-1 can be formed from any one of copper (Cu), magnesium (Mg) and silver (Ag) or an alloy thereof.
[0046] The first alloy forming layer 230A-1 is formed on the first electrode diffusion layer 220A-1. The first alloy forming layer 230A-1 is an alloyed layer formed by applying heat to the contact surface between the first electrode diffusion layer 220A-1 and the main electrode layer 240A.
[0047] Figure 2 This is a reference diagram showing the formation of the first alloy forming layer 230A-1 by applying heat to the contact surface between the first electrode diffusion layer 220A-1 and the main electrode layer 240A.
[0048] To achieve thermal diffusion at the interface between the first electrode diffusion layer 220A-1 and the main electrode layer 240A, a heat treatment is applied for 1 hour or longer at a high temperature (e.g., 200°C or higher) equal to or below the melting temperature of the metallic material. After the heat treatment, the structure is slowly cooled to remove internal stress. The heat treatment forms the first alloy forming layer 230A-1, causing distortion in the crystal lattice and thereby hindering the movement of dislocations.
[0049] The first alloy forming layer 230A-1 may be formed from an alloy including at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
[0050] The main electrode layer 240A is formed on the first alloy forming layer 230A-1. The main electrode layer 240A can be formed from any one of copper (Cu), aluminum (Al), and platinum (Pt) or an alloy thereof.
[0051] The second alloy forming layer 230A-2 is formed on the main electrode layer 240A. The second alloy forming layer 230A-2 is an alloyed layer formed by applying heat to the contact surface between the second electrode diffusion layer 220A-2 formed on the second alloy forming layer 230A-2 and the main electrode layer 240A.
[0052] The second alloy forming layer 230A-2 may be formed from an alloy including at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
[0053] The second electrode diffusion layer 220A-2 is formed on the second alloy forming layer 230A-2 and disposed on the main electrode layer 240A to enhance the strength of the main electrode layer 240A.
[0054] The second electrode diffusion layer 220A-2 can be formed from any one of copper (Cu), magnesium (Mg) and silver (Ag) or an alloy thereof.
[0055] A connection layer 250A is formed on the second electrode diffusion layer 220A-2 to connect the wiring layer formed on the connection layer 250A to the IDT electrode layer 200A.
[0056] The average thickness of the first electrode diffusion layer 220A-1, the second electrode diffusion layer 220A-2, and the main electrode layer 240A can satisfy the following equation 1.
[0057] Equation 1
[0058] 0.05≤(Td1+Td2) / Tm≤0.18
[0059] In Equation 1, Td1 represents the average thickness of the first electrode diffusion layer 220A-1, Td2 represents the average thickness of the second electrode diffusion layer 220A-2, and Tm represents the average thickness of the main electrode layer 240A.
[0060] The thicker the 240A main electrode layer, the greater the required thickness of the high-strength alloying layer must be. If (Td1+Td2) / Tm is less than 0.05, it cannot provide a minimum alloying layer thickness sufficient to prevent fracture. Simultaneously, while electrical durability increases with a thicker alloying layer, electrical properties deteriorate. Therefore, to ensure a minimum thickness to prevent electrical property degradation while maintaining the required electrical durability, (Td1+Td2) / Tm must be below 0.18.
[0061] Therefore, in order to ensure sufficient alloy layer thickness required to strengthen the main electrode layer 240A while minimizing the degradation of the product's electrical properties, it is necessary to satisfy 0.05≤(Td1+Td2) / Tm≤0.18.
[0062] Figure 3 The lifespan of the SAW device according to the first embodiment of this disclosure was compared with that of conventional technology.
[0063] refer to Figure 3 As can be seen, at a temperature of 145°C and a power of 34dBm, the SAW device according to the first embodiment of this disclosure has a lifespan of 4000 minutes, which is significantly longer than the 500 minutes of conventional technology.
[0064] Figure 4 The structure of a SAW device according to a second embodiment of the present disclosure is shown.
[0065] The piezoelectric substrate 100B can be one of a silicon substrate, a diamond substrate, a sapphire substrate, a silicon carbide substrate, a LiNbO3 substrate, and a LiTaO3 substrate.
[0066] An IDT electrode layer 200B is formed on the piezoelectric substrate 100B, and multiple electrode layers are alternately arranged at equal intervals along the horizontal direction in the IDT electrode layer 200B.
[0067] like Figure 4 As shown, the IDT electrode layer 200B includes an adhesive layer 210B, an electrode diffusion layer 220B, an alloy forming layer 230B, a first main electrode layer 240B-1, an electrode diffusion suppression layer 250B, a second main electrode layer 240B-2, and a connecting layer 260B.
[0068] The adhesive layer 210B is used to bond the layers forming the IDT electrode layer 200B to the piezoelectric substrate 100B. The adhesive layer 210B is formed on the piezoelectric substrate 100B.
[0069] The adhesive layer 210B may be formed from at least one material selected from titanium, alumina (Al2O3), titanium nitride (TiN), chromium (Cr), zirconium (Zr), hafnium oxide (HfO2), titanium oxide (TiO2), and tantalum pentoxide (Ta2O5).
[0070] An electrode diffusion layer 220B is formed on the adhesive layer 210B and disposed below the first main electrode layer 240B-1 to enhance the strength of the first main electrode layer 240B-1.
[0071] The electrode diffusion layer 220B can be formed from any one of copper (Cu), magnesium (Mg) and silver (Ag) or an alloy thereof.
[0072] An alloy forming layer 230B is formed on the electrode diffusion layer 220B. The alloy forming layer 230B is an alloyed layer formed by applying heat to the contact surface between the electrode diffusion layer 220B and the first main electrode layer 240B-1.
[0073] The alloy forming layer 230B can be formed from an alloy including at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
[0074] The first main electrode layer 240B-1 is formed on the alloy forming layer 230B. The first main electrode layer 240B-1 can be formed from any one of copper (Cu), aluminum (Al), and platinum (Pt) or their alloys.
[0075] An electrode diffusion suppression layer 250B is formed on the first main electrode layer 240B-1 to prevent metal spraying and diffusion caused by damage to the first main electrode layer 240B-1 or the second main electrode layer 240B-2.
[0076] Therefore, the electrode diffusion suppression layer 250B can be formed from any of the following materials or alloys: chromium (Cr), titanium (Ti), nickel (Ni), zirconium (Zr), and titanium nitride (TiN).
[0077] The second main electrode layer 240B-2 is formed on the electrode diffusion suppression layer 250B. The second main electrode layer 240B-2 may be formed of any one of copper (Cu), aluminum (Al) and platinum (Pt) or an alloy thereof.
[0078] A connection layer 260B is formed on the second main electrode layer 240B-2 to connect the wiring layer formed on the connection layer 260B to the IDT electrode layer 200B.
[0079] The average thickness of each of the first main electrode layer 240B-1, the second main electrode layer 240B-2, and the electrode diffusion suppression layer 250B can satisfy Equation 2.
[0080] Equation 2
[0081] 0.04≤(Tb) / (Tm1+Tm2)≤0.15
[0082] In Equation 2, Tm1 represents the average thickness of the first main electrode layer 240B-1, Tm2 represents the average thickness of the second main electrode layer 240B-2, and Tb represents the average thickness of the electrode diffusion suppression layer 250B.
[0083] The electrode diffusion suppression layer 250B must have a thickness of not less than 0.04, which is the minimum thickness required for use as an electrode diffusion suppression layer when the thickness of the first main electrode layer 240B-1 or the second main electrode layer 240B-2 increases.
[0084] Furthermore, as the thickness of the electrode diffusion suppression layer 250B increases, the degradation of the electrical properties of the first main electrode layer 240B-1 or the second main electrode layer 240B-2 becomes more pronounced. Therefore, in order to prevent diffusion while avoiding degradation of electrical properties, the thickness ratio (Tb) / (Tm1+Tm2) must be less than 0.15.
[0085] Therefore, in order to minimize the degradation of the electrical properties of the product while ensuring sufficient thickness for anti-diffusion, it is necessary to satisfy 0.04≤(Tb) / (Tm1+Tm2)≤0.15.
[0086] Figure 5 The lifespan of the SAW device according to the second embodiment of this disclosure was compared with that of devices in the related art.
[0087] refer to Figure 5 It can be seen that at a temperature of 145°C and a power of 34 dBm, the SAW device according to the second embodiment of this disclosure has a significantly longer lifespan (3800 min) than the devices of the related art (500 min).
[0088] Figure 6 The structure of a SAW device according to a third embodiment of the present disclosure is shown.
[0089] The piezoelectric substrate 100C can be one of the following: silicon substrate, diamond substrate, sapphire substrate, silicon carbide substrate, LiNbO3 substrate, and LiTaO3 substrate.
[0090] An IDT electrode layer 200C is formed on a piezoelectric substrate 100C, and multiple electrode layers are alternately arranged at equal intervals along the horizontal direction in the IDT electrode layer 200C.
[0091] like Figure 6 As shown, the IDT electrode layer 200C includes an adhesive layer 210C, a first electrode diffusion layer 220C-1, a first alloy forming layer 230C-1, a first main electrode layer 240C-1, an electrode diffusion suppression layer 250C, a second main electrode layer 240C-2, a second alloy forming layer 230C-2, a second electrode diffusion layer 220C-2, and a connecting layer 260C.
[0092] The adhesive layer 210C is used to bond the layers forming the IDT electrode layer 200C to the piezoelectric substrate 100C. The adhesive layer 210C is formed on the piezoelectric substrate 100C.
[0093] The adhesive layer 210C can be formed from at least one material selected from titanium, alumina (Al2O3), titanium nitride (TiN), chromium (Cr), zirconium (Zr), hafnium oxide (HfO2), titanium oxide (TiO2), and tantalum pentoxide (Ta2O5).
[0094] The first electrode diffusion layer 220C-1 is formed on the adhesive layer 210C and disposed below the first main electrode layer 240C-1 to enhance the strength of the first main electrode layer 240C-1.
[0095] The first electrode diffusion layer 220C-1 can be formed from any one of copper (Cu), magnesium (Mg) and silver (Ag) or an alloy thereof.
[0096] The first alloy forming layer 230C-1 is formed on the first electrode diffusion layer 220C-1. The first alloy forming layer 230C-1 is an alloyed layer formed by applying heat to the contact surface between the first electrode diffusion layer 220C-1 and the first main electrode layer 240C-1.
[0097] The first alloy forming layer 230C-1 may be formed from an alloy including at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
[0098] The first main electrode layer 240C-1 is formed on the first alloy forming layer 230C-1. The first main electrode layer 240C-1 can be formed from any one of copper (Cu), aluminum (Al) and platinum (Pt) or an alloy thereof.
[0099] An electrode diffusion suppression layer 250C is formed on the first main electrode layer 240C-1 to prevent metal spraying and diffusion caused by damage to the first main electrode layer 240C-1 or the second main electrode layer 240C-2.
[0100] The electrode diffusion suppression layer 250C can be formed from any of the following materials or alloys: chromium (Cr), titanium (Ti), nickel (Ni), zirconium (Zr), and titanium nitride (TiN).
[0101] The second main electrode layer 240C-2 is formed on the electrode diffusion suppression layer 250C. The second main electrode layer 240C-2 can be formed of any one of copper (Cu), aluminum (Al) and platinum (Pt) or an alloy thereof.
[0102] The second alloy forming layer 230C-2 is formed on the second main electrode layer 240C-2. The second alloy forming layer 230C-2 is an alloying layer formed by applying heat to the contact surface between the second electrode diffusion layer 220C-2 and the second main electrode layer 240C-2.
[0103] The second alloy forming layer 230C-2 can be formed from an alloy including at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
[0104] The second electrode diffusion layer 220C-2 is formed on the second alloy forming layer 230C-2 and disposed on the second main electrode layer 240C-2 to enhance the strength of the second main electrode layer 240C-2.
[0105] The second electrode diffusion layer 220C-2 can be formed from any one of copper (Cu), magnesium (Mg) and silver (Ag) or an alloy thereof.
[0106] A connection layer 260C is formed on the second electrode diffusion layer 220C-2 to connect the wiring layer formed on the connection layer 260C to the IDT electrode layer 200C.
[0107] The average thickness of each of the first main electrode layer 240C-1, the second main electrode layer 240C-2, and the electrode diffusion suppression layer 250C can satisfy the following equation 3:
[0108] Equation 3
[0109] 0.04≤(Tb) / (Tm1+Tm2)≤0.15
[0110] In Equation 3, Tm1 represents the average thickness of the first main electrode layer 240C-1, Tm2 represents the average thickness of the second main electrode layer 240C-2, and Tb represents the average thickness of the electrode diffusion suppression layer 250C.
[0111] According to this disclosure, for the IDT electrode layer of a SAW device, a first electrode diffusion layer and a second electrode diffusion layer can be formed between the main electrode layers, or an electrode diffusion suppression layer can be formed between the first main electrode layer and the second main electrode layer, thereby providing high heat resistance and high power durability for the IDT electrode of the SAW device. Therefore, compared with related technologies, the SAW device of this disclosure can extend the life of the SAW device by increasing the durability of the electrodes.
[0112] Although the technical concept of this disclosure has been described above with reference to the accompanying drawings, these are merely examples of preferred embodiments of this disclosure and are not intended to limit the scope of this disclosure.
[0113] Therefore, this disclosure is not limited to the specific preferred embodiments described above, and various modifications can be made by those skilled in the art without departing from the spirit and scope of this disclosure as defined by the appended claims, and such modifications are intended to fall within the scope of the appended claims.
Claims
1. A surface acoustic wave (SAW) device, comprising: Piezoelectric substrate, and An IDT electrode layer is formed on the piezoelectric substrate, the IDT electrode layer comprising: An adhesive layer for bonding to the piezoelectric substrate; A first electrode diffusion layer is formed on the adhesive layer; A first alloy forming layer is formed on the first electrode diffusion layer; A main electrode layer, wherein the main electrode layer is formed on the first alloy forming layer; A second alloy forming layer is formed on the main electrode layer; A second electrode diffusion layer is formed on the second alloy forming layer; and A connection layer is formed on the second electrode diffusion layer.
2. The SAW device according to claim 1, wherein, Each of the first electrode diffusion layer and the second electrode diffusion layer is formed of any one of copper (Cu), magnesium (Mg) and silver (Ag) or an alloy thereof.
3. The SAW device according to claim 1, wherein, The main electrode layer is formed of any one of copper (Cu), aluminum (Al), and platinum (Pt) or an alloy thereof.
4. The SAW device according to claim 1, wherein, Each of the first alloy forming layer and the second alloy forming layer is formed of an alloy comprising at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
5. The SAW device according to claim 1, wherein, The average thickness of each of the first electrode diffusion layer, the second electrode diffusion layer, and the main electrode layer satisfies the following equation: 0.05≤(Td1+Td2) / Tm≤0.18 Wherein, Td1 represents the average thickness of the first electrode diffusion layer, Td2 represents the average thickness of the second electrode diffusion layer, and Tm represents the average thickness of the main electrode layer.
6. A surface acoustic wave (SAW) device, comprising: Piezoelectric substrate, and An IDT electrode layer is formed on the piezoelectric substrate, the IDT electrode layer comprising: An adhesive layer for bonding to the piezoelectric substrate; An electrode diffusion layer is formed on the adhesive layer; An alloy forming layer is formed on the electrode diffusion layer; A first main electrode layer is formed on the alloy forming layer; An electrode diffusion suppression layer is formed on the first main electrode layer; A second main electrode layer is formed on the electrode diffusion suppression layer; and A connection layer is formed on the second main electrode layer.
7. The SAW apparatus according to claim 6, wherein, The electrode diffusion layer is formed of any one of copper (Cu), magnesium (Mg), and silver (Ag) or an alloy thereof.
8. The SAW apparatus according to claim 6, wherein, Each of the first main electrode layer and the second main electrode layer is formed of any one of copper (Cu), aluminum (Al) and platinum (Pt) or an alloy thereof.
9. The SAW apparatus according to claim 6, wherein, The alloy forming layer is formed of an alloy comprising at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
10. The SAW apparatus according to claim 6, wherein, The electrode diffusion suppression layer is formed of any one of the following materials or alloys: chromium (Cr), titanium (Ti), nickel (Ni), zirconium (Zr), and titanium nitride (TiN).
11. The SAW apparatus according to claim 6, wherein, The average thickness of each of the first main electrode layer, the second main electrode layer, and the electrode diffusion suppression layer satisfies the following equation: 0.04≤(Tb) / (Tm1+Tm2)≤0.15 Wherein, Tm1 represents the average thickness of the first main electrode layer, Tm2 represents the average thickness of the second main electrode layer, and Tb represents the average thickness of the electrode diffusion suppression layer.
12. A surface acoustic wave (SAW) device, comprising: Piezoelectric substrate, and An IDT electrode layer is formed on the piezoelectric substrate, the IDT electrode layer comprising: An adhesive layer for bonding to the piezoelectric substrate; A first electrode diffusion layer is formed on the adhesive layer; A first alloy forming layer is formed on the first electrode diffusion layer; A first main electrode layer is formed on the first alloy forming layer; An electrode diffusion suppression layer is formed on the first main electrode layer; A second main electrode layer is formed on the electrode diffusion suppression layer; A second alloy forming layer is formed on the second main electrode layer; A second electrode diffusion layer is formed on the second alloy forming layer; and A connection layer is formed on the second electrode diffusion layer.
13. The SAW apparatus according to claim 12, wherein, Each of the first electrode diffusion layer and the second electrode diffusion layer is formed of any one of copper (Cu), magnesium (Mg) and silver (Ag) or an alloy thereof.
14. The SAW apparatus according to claim 12, wherein, Each of the first main electrode layer and the second main electrode layer is formed of any one of copper (Cu), aluminum (Al) and platinum (Pt) or an alloy thereof.
15. The SAW apparatus according to claim 12, wherein, Each of the first alloy forming layer and the second alloy forming layer is formed of an alloy comprising at least one of copper (Cu), magnesium (Mg) and silver (Ag) and at least one of aluminum (Al) and platinum (Pt).
16. The SAW apparatus according to claim 12, wherein, The electrode diffusion suppression layer is formed of any one of the following materials or alloys: chromium (Cr), titanium (Ti), nickel (Ni), zirconium (Zr), and titanium nitride (TiN).
17. The SAW apparatus according to claim 12, wherein, The average thickness of each of the first main electrode layer, the second main electrode layer, and the electrode diffusion suppression layer satisfies the following equation: 0.04≤(Tb) / (Tm1+Tm2)≤0.15 Wherein, Tm1 represents the average thickness of the first main electrode layer, Tm2 represents the average thickness of the second main electrode layer, and Tb represents the average thickness of the electrode diffusion suppression layer.