WO2014075222A1 - Spr sensor and manufacturing method thereof - Google Patents

Abstract

An SPR sensor is provided, comprising: a substrate (11), which is made of transparent inorganic material; an adhesion layer (12) formed on the substrate (11), which is made of Cr or Ti; an adhesion enhancing layer (13) formed on the adhesion layer (12), which is made of Au or Au containing alloy; a metal functional layer (14) formed on the adhesion enhancing layer (13), which is made of Ag. By inserting the adhesion enhancing layer (13) made of Au or Au containing alloy between the Cr or Ti adhesion layer (12) and the Ag metal functional layer (14), the metal functional layer (14) made of Ag is firmly adhered to the transparent inorganic substrate (11) to ensure the long term stability of the performance of the SPR sensor.

Description

 SPR sensor and preparation method thereof

 The invention relates to a surface plasmon resonance (SPR) sensor device and a preparation method thereof, in particular to an SPR sensor device having a silver functional layer and a preparation method thereof. Background technique

 Surface Plasmon Resonance (SPR) sensor is a sensor that can detect subtle changes in the optical properties of the medium to be tested (such as dielectric thickness, refractive index, etc.). The core component is a metal functional layer. The surface plasma wave (surface Plasmon Wave, called SPW) at the interface between the metal functional layer and the medium to be tested realizes the detection near the interface.

 SPR sensors are typically constructed of a metallic functional layer and a substrate that supports the metallic functional layer. The substrate needs to be transparent and smooth to ensure the excitation of SPR and to facilitate the measurement of resonance conditions. The substrate material also needs to be hard and has strong adhesion to the metal to ensure a long service life and long-term stability of the SPR sensor. Sex. At present, commonly used substrate materials include silicon-based inorganic materials such as glass, quartz, and silicon wafers, and polymer materials such as polycarbonate and cyclic olefin copolymer. Compared with polymer materials, the above inorganic materials are widely used because of their advantages of better finish and flatness, stronger adhesion to metals, wide range of sources, and ease of processing.

 The metal functional layer of the SPR sensor can be made of metal such as gold, silver, copper, iron, aluminum, etc. Among them, silver has good compatibility with biological and chemical materials, and is the most commonly used and most excellent material for preparing the metal functional layer of SPR sensor. . In addition, a protective layer or a modified layer can be formed on the Ag metal functional layer to further improve the performance of the SPR sensor.

Due to the advantages of the above-described substrate composed of a silicon-based inorganic material and the excellent performance of the above-described silver metal functional layer, it is desirable to combine a substrate composed of a silicon-based inorganic material with a silver metal functional layer to improve the overall performance of the SPR sensor. However, the adhesion between silver and a silicon-based inorganic material substrate is relatively poor. In the prior art, silver is usually adhered to a silicon-based inorganic material substrate by a chromium layer or a titanium layer as an adhesion layer. Although chromium and titanium can achieve good adhesion to silicon-based inorganic material substrates, the adhesion between chromium or titanium and silver metal functional layers is not good, and it is far from the need to achieve long-term stable SPR sensors. Adhesion. Summary of the invention

 Accordingly, it is an object of the present invention to provide an SPR sensor and a method of fabricating the same that can enhance adhesion between a silver metal functional layer and a substrate to achieve long-term stability of the SPR sensor.

 The invention provides an SPR sensor, comprising:

 a substrate made of a transparent inorganic material;

 An adhesion layer on the substrate, made of Cr or Ti;

 An adhesion enhancing layer on the adhesion layer, made of Au or an Au-containing alloy;

 The metal functional layer on the adhesion enhancing layer is made of Ag.

 A sensor according to the present invention, wherein the material of the substrate is a silicon-based inorganic material. A sensor according to the present invention, wherein the material of the substrate is glass, quartz or silicon. A sensor according to the present invention, wherein the material of the substrate is sapphire or barium titanate. A sensor according to the present invention, wherein the substrate is prismatic.

 A sensor according to the present invention, wherein the Au-containing alloy constituting the adhesion enhancing layer is

Au-Ag alloy, Au-Cu alloy, Au-Cr alloy, Au-Pt alloy, Au-Zr alloy or Au-Ti alloy.

 A sensor according to the present invention, wherein the adhesion enhancing layer has a thickness of from 1 nm to 10 nm. A sensor according to the invention further comprises a surface modifying layer or a protective layer on the metallic functional layer.

 The invention also provides a method for preparing the above sensor, comprising:

 1) forming an adhesion layer made of Cr or Ti on a substrate made of a transparent inorganic material;

2) forming an adhesion enhancing layer made of Au or an Au-containing alloy on the adhesion layer;

 3) A metal functional layer made of Ag is formed on the adhesion enhancing layer.

 The method provided in accordance with the present invention further includes forming a surface modification layer or a protective layer on the metal functional layer.

 In the SPR sensor provided by the present invention, the metal functional layer made of Ag is firmly adhered by inserting an adhesion enhancing layer made of Au or an Au alloy between the Cr or Ti adhesion layer and the Ag metal functional layer. On the inorganic material substrate to ensure long-term stability of SPR sensor performance. DRAWINGS

 The embodiments of the present invention are further described below with reference to the accompanying drawings, wherein:

 1 is a schematic structural view of an SPR sensor according to Embodiment 1 of the present invention;

Figure 2 shows the normalized reflected light intensity versus incident angle of the SPR sensor shown in Figure 1. Response result

 Figure 3 shows a partial enlarged view of the vicinity of 53° in Figure 2;

 4 is a view showing a change in sensitivity of the SPR sensor shown in FIG. 1 within 33 days; FIG. 5 is a schematic structural view of an SPR sensor according to Embodiment 2 of the present invention;

 Figure 6 is a test result of the sensitivity of the SPR sensor shown in Figure 5;

 Figure 7 is a block diagram showing the structure of an SPR sensor according to Embodiment 3 of the present invention. detailed description

 In order to make the objects, technical solutions and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the specific embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Example 1

 This embodiment provides an SPR sensor, and its structure is as shown in FIG. 1 , including:

 Substrate 11 , made of glass;

 The adhesion layer 12 on the substrate 11 is made of Cr and has a thickness of 2.5 nm;

 The adhesion enhancing layer 13 on the adhesion layer 12 is made of Au and has a thickness of 2 nm;

 The metal functional layer 14 on the adhesion enhancing layer 13 is made of Ag and has a thickness of 50 nm;

The surface modification layer 15 is composed of a carboxyl group-(ethylene glycol) ₆ -thiol formed by a single molecule self-assembly method. In the SPR sensor provided in this embodiment, an adhesion enhancement layer 13 made of Au is interposed between the Cr adhesion layer 12 and the Ag metal functional layer 14, and since the adhesion between Au and Cr and Ag is strong, it is capable of The metal functional layer made of Ag is firmly adhered to the Cr adhesion layer, and the adhesion between Cr and the silicon-based inorganic material substrate is strong, so that the Ag metal functional layer can be firmly adhered to the substrate. On, to ensure the long-term stability of SPR sensor performance.

To illustrate the advantages of the SPR sensor provided by this embodiment, the performance of the SPR sensor was tested. In the test, an SF10 glass prism was used as a coupler, and the incident beam wavelength was 660 nm. The test object was deionized water, and the flow rate of the deionized water was 3 μl/sec. 2 and 3 show the first day, the third day, the fifth day, the tenth day, the twelfth day, the 17th day, the 27th day, the 31st day, respectively, after the preparation of the SPR sensor is completed. 3 is a partial enlarged view of FIG. 2 . The curves in FIG. 3 are the results measured on the first day, the third day, the fifth day, the twelfth day, the 31st day, the 17th day, the tenth day, and the 27th day from left to right. As shown in Figure 2 and Figure 3, after 31 days of contact with deionized water, this implementation The normalized reflected light intensity of the SPR sensor provided by the example is substantially coincident with the incident angle, indicating that the normalized reflected light intensity of the SPR sensor has little change in response to the incident angle, indicating that the silver metal functional layer 14 of the above SPR sensor The adhesion to the glass substrate layer 11 is strong, and has good long-term stability in a liquid medium environment.

 The result shown in Figure 4 is that the incident angle is fixed to the left of the resonance absorption peak shown in Figure 2 within 33 days.

At 20% depth, 25 points were randomly selected from the surface of the surface modification layer 15 to measure the sensitivity of the difference between the reflected light intensity by measuring the difference between the deionized water and the 1% mass fraction of the glycerin aqueous solution. The results show that the sensitivity of the SPR sensor structure is maintained at around 9000%/RIU for 33 days, and the sensitivity variance between the above 25 points remains between 120-180%/RIU after the first day, indicating that the surface of the surface modification layer 15 is Good hook and low roughness.

 According to an embodiment of the present invention, a method for manufacturing an SPR sensor is provided, comprising: 1) cleaning a substrate 11 and placing it in an electron beam evaporation instrument;

 2) vapor-depositing a 2.5 nm thick Cr adhesion layer 12 and a 2 nm thick Au adhesion enhancement layer 13 at a rate of 0.1 nm per second, and then vapor-depositing a 50 nm thick Ag metal functional layer at a rate of 0.08 nm per second. 14;

3) immersing the substrate 11 in a carboxy-(ethylene glycol) ₆ -thiol solution for 12 hours to form a surface modification layer 15 on the surface of the Ag metal functional layer 14, wherein the carboxy-(ethylene glycol) ₆ -thiol Ag solution The solvent is alcohol, and the concentration of carboxyl-(ethylene glycol) ₆ -thiol is lmM. Example 2

 The embodiment provides an SPR sensor, and the structure thereof is as shown in FIG. 5, including: a substrate 21 made of glass;

 An adhesion layer 22 on the substrate 21, made of Ti, having a thickness of 5 nm;

 The adhesion enhancing layer 23 on the adhesion layer 22 is made of Au and has a thickness of 2 nm;

 The metal functional layer 24 on the adhesion enhancing layer 23 is made of Ag and has a thickness of 42 nm;

 a protective layer 25 on the metal functional layer 24, made of Au, having a thickness of 13 nm;

 The surface modification layer 26 on the protective layer 25 is composed of decylundecanoic acid formed by a single molecule self-assembly method;

 Protein G on the surface modification layer 26 Biomolecular layer 27.

In the SPR sensor provided in this embodiment, an adhesion enhancement layer made of Au is interposed between the Ti adhesion layer and the Ag metal functional layer, and since the adhesion between Au and Ti and Ag is strong, the system can be made of Ag. The metal functional layer is firmly adhered to the Ti adhesion layer, while the Ti and the silicon substrate are not The adhesion between the substrate of the machine material is strong, so that the Ag metal functional layer can be firmly adhered to the substrate, thereby ensuring the long-term stability of the SPR sensor performance.

 To illustrate the advantages of the SPR sensor provided by this embodiment, the performance of the SPR sensor was tested. Using SF10 glass prism as the coupler, the incident angle is fixed at the depth of 30% of the left side of the resonance absorption peak of the SPR sensor structure provided by the present embodiment under the condition of the incident beam wavelength of 660 nm, and lx and 2x phosphoric acid are selected within 510 minutes. The buffer salt solution measures the difference in reflected light intensity to calculate the sensitivity. The test results are shown in Figure 6. The sensitivity of the SPR sensor is about 6000%/RIU after contact with different liquid mediums in 510 minutes. The sensitivity variance between different spots is kept between 120-200%/RIU. The surface modification layer 26 has good surface uniformity and low roughness.

 According to an embodiment of the present invention, a method for manufacturing an SPR sensor is provided, including:

1) after cleaning the substrate 21, it is placed in an electron beam evaporation instrument;

 2) depositing a 5 nm thick Ti adhesion layer 22 and a 2 nm thick Au adhesion enhancement layer 23 at a rate of O.Olnm per second, and then evaporating a 42 nm thick Ag metal functional layer 24 at a rate of 0.25 nm per second. And then vapor-depositing a 13 nm thick Au protective layer 25 at a rate of O.Olnm per second;

 3) immersing the substrate 11 in the decylundecanoic acid solution for 12 hours, forming a surface modification layer 26 on the surface of the Au protective layer 25, wherein the concentration of the decylundecanoic acid solution is 1 mM, and the solvent is alcohol;

4) Use 0.2M ethyl(dimethylaminopropyl)carbodiimide (Cylinder called EDC) and 0.1M N-Hydroxysuccinimide (N-Hydroxysuccinimide) , the cartridge is called NHS) The mixture is activated for 15 minutes on the surface of the surface 4 enamel layer 26;

 5) Remove the EDC/NHS mixture, wash it with deionized water, and dry the substrate 21 with high-purity nitrogen, and use a pipette tip to point 15 protein G spot points on the surface of the surface modification layer 26 to form a biomolecular layer. 27. Example 3

 This embodiment provides an SPR sensor, and its structure is as shown in FIG. 7, which includes:

 The substrate 31, made of quartz, has a prism shape, has the same shape as the coupler, and functions as a coupler;

The adhesion layer 32 on one side of the prism-shaped substrate 31 is made of Cr and has a thickness of 5 nm; the adhesion enhancement layer 33 on the adhesion layer 32 is made of an Au-Ti alloy and has a thickness of 2 nm; a metal functional layer 34 on layer 33, made of Ag, having a thickness of 42 nm; The protective layer 35 on the metal functional layer 34 is made of Au and has a thickness of 13 nm.

 In the SPR sensor provided in this embodiment, an adhesion enhancement layer made of an Au-Ti alloy is interposed between the Cr adhesion layer and the Ag metal functional layer, and the adhesion of the Au-Ti alloy to Ti and Ag is strong. Therefore, the metal functional layer made of Ag can be firmly adhered to the Cr adhesion layer, and the adhesion between the Cr and the silicon-based inorganic material substrate is strong, so that the Ag metal functional layer can be firmly adhered. Attached to the substrate to ensure long-term stability of the SPR sensor performance.

 According to an embodiment of the present invention, a method for manufacturing an SPR sensor is provided, including:

1) After cleaning the prism-shaped substrate 31, it is placed in an electron beam evaporation instrument;

 2) A 5 nm thick Cr adhesion layer 32 and a 2 nm thick Au-Ti alloy adhesion enhancement layer 33 were sequentially deposited at a rate of O.Olnm per second, and then evaporated at a rate of 0.25 nm per second to a thickness of 42 nm.

The Ag metal functional layer 34 is then vapor-deposited with a 13 nm thick Au protective layer 35 at a rate of O.Olnm per second.

 According to other embodiments of the present invention, in addition to the Au and Au-Ti alloys described above, the adhesion enhancing layer may be made of other Au-containing alloys, such as Au-Ag alloys, Au-Cu alloys,

Au-Cr alloy, Au-Pt alloy, Au-Zr alloy, Au-Ti alloy, and the like.

 According to other embodiments of the present invention, the adhesion enhancing layer may have a thickness of from 1 nm to 10 nm.

 According to other embodiments of the present invention, the substrate is a silicon-based inorganic material such as glass, quartz, silicon wafer, etc., and may also be other transparent inorganic materials such as sapphire, barium titanate or the like.

 According to other embodiments of the present invention, wherein the substrate is preferably prismatic, the substrate is integrated with the coupler to avoid the negative effects of poor bonding between the substrate and the coupler.

 The present invention has good adhesion between Au and Ag, Ti and Cr by inserting an adhesion enhancing layer made of Au or an Au-containing alloy between the Ti or Cr adhesion layer and the Ag metal functional layer. The metal functional layer made of Ag is firmly adhered to the substrate, thereby ensuring the long-term stability of the SPR sensor performance.

 It should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention and are not limiting. While the invention has been described in detail herein with reference to the embodiments of the embodiments of the present invention Within the scope of the claims.

Claims

Rights request 1. An SPR sensor, comprising:  a substrate made of a transparent inorganic material;  An adhesion layer on the substrate, made of Cr or Ti;  An adhesion enhancing layer on the adhesion layer, made of Au or an Au-containing alloy;  The metal functional layer on the adhesion enhancing layer is made of Ag.  The sensor according to claim 1, wherein the material of the substrate is a silicon-based inorganic material.  3. The sensor according to claim 2, wherein the material of the substrate is glass, quartz or silicon.  4. The sensor of claim 1 wherein the material of the substrate is sapphire or barium titanate.  5. The sensor of claim 1 wherein the substrate is prism shaped.  6. The sensor according to claim 1, wherein the Au-containing alloy constituting the adhesion enhancing layer is an Au-Ag alloy, an Au-Cu alloy, an Au-Cr alloy, an Au-Pt alloy, an Au-Zr alloy or Au. -Ti alloy.  The sensor according to claim 1, wherein the adhesion enhancing layer has a thickness of from 1 nm to 10 nm.  8. The sensor of claim 1 further comprising a surface modification layer or a protective layer on the metal functional layer.  9. A method of making the sensor of claim 1 comprising:  1) forming an adhesion layer made of Cr or Ti on a substrate made of a transparent inorganic material; 2) forming an adhesion enhancing layer made of Au or an Au-containing alloy on the adhesion layer;  3) A metal functional layer made of Ag is formed on the adhesion enhancing layer.  10. The method of claim 9 further comprising forming a surface finish or protective layer on the metallic functional layer.