阅读说明：本技术 一种离子注入制作sers基底的方法 (Method for manufacturing SERS substrate through ion implantation ) 是由 远雁 李超波 刘丽花 解婧 王欢 于 2019-04-29 设计创作，主要内容包括：本发明实施例提供的一种离子注入制作SERS基底的方法,包括：采用等离子体浸没离子注入的方式对单晶硅进行处理,使单晶硅的表面形成纳米柱阵列结构；在形成有纳米柱阵列的单晶硅表面蒸镀贵金属膜,使纳米柱阵列结构的侧壁上形成贵金属纳米点阵列,获得SERS基底；本发明制作的SERS基底,增强了基底的拉曼信号,解决了现有技术中基底纳米点阵列不够灵敏的缺点。(The embodiment of the invention provides a method for manufacturing a SERS substrate by ion implantation, which comprises the following steps: processing the monocrystalline silicon by adopting a plasma immersion ion injection mode to form a nano-pillar array structure on the surface of the monocrystalline silicon; evaporating a noble metal film on the surface of the monocrystalline silicon on which the nano-pillar array is formed, so that a noble metal nano-point array is formed on the side wall of the nano-pillar array structure, and an SERS substrate is obtained; the SERS substrate manufactured by the invention enhances the Raman signal of the substrate and solves the defect that the substrate nano-dot array is not sensitive enough in the prior art.)

1. A method of ion implantation for fabricating a SERS substrate, comprising:

processing the monocrystalline silicon by adopting a plasma immersion ion injection mode to form a nano-pillar array structure on the surface of the monocrystalline silicon;

And (3) evaporating a noble metal film on the surface of the monocrystalline silicon with the nano-pillar array, so that a noble metal nano-point array is formed on the side wall of the nano-pillar array structure, and an SERS substrate is obtained.

2. The method of claim 1, wherein obtaining the SERS substrate comprises:

and carrying out He plasma injection on the monocrystalline silicon subjected to the precious metal film evaporation to obtain the SERS substrate.

3. The method of claim 1, wherein the processing of single crystal silicon by plasma immersion ion implantation comprises:

and processing the monocrystalline silicon by adopting a low-energy plasma immersion ion implantation mode.

4. The method of claim 1, wherein the nanopillar array structure has a height of 2-2.5 um.

5. The method as claimed in claim 1, wherein the width of the nanopillar array structure is 300-900 nm.

6. The method of claim 1, wherein the processing of single crystal silicon by plasma immersion ion implantation comprises:

by using SF₆Gas as etching gas, O₂As a protective gas, single crystal silicon is treated by plasma immersion ion implantation.

7. The method according to claim 1, wherein the step of depositing a noble metal film on the surface of the single crystal silicon on which the nanopillar array is formed comprises:

and evaporating a noble metal film on the surface of the monocrystalline silicon on which the nano-pillar array is formed by adopting an electron beam evaporation mode.

8. The method of claim 1 or 7, wherein the noble metal is gold, silver, copper, or platinum.

9. The method according to claim 1, wherein an implantation power for performing He plasma implantation on the single crystal silicon after the deposition of the noble metal film is: 30W-100W.

10. The method according to claim 1, wherein an implantation time for performing He plasma implantation on the silicon single crystal after the deposition of the noble metal film is: 10s-60 s.

Technical Field

The invention relates to the technical field of surface-enhanced Raman substrate manufacturing, in particular to a method for manufacturing an SERS substrate through ion implantation.

Background

Surface Enhanced Raman Scattering (SERS) is an ultrasensitive, non-destructive identification and molecular recognition technique. Because the SERS technology has rapid, simple and nondestructive qualitative and quantitative analysis, the SERS technology is widely applied to the fields of organic chemistry, material science, biological detection, food safety, medical treatment and the like. At present, the mechanism and application of the SERS effect have become a topical problem in current international research.

Both in the research of SERS and the application of SERS, a SERS substrate with excellent performance needs to be manufactured, and therefore, the manufacturing of the SERS substrate is an important point for the application and research of SERS. At present, most SERS substrates adopt different methods such as nanosphere imprinting, metal sol method, AAO (anodic aluminum oxide) template method, etc. to fabricate nano array structures of different shapes, such as nanowires, nanodots, nanopillars, nanocones, etc., on the surface of the substrate. Although the existing method can manufacture ordered and reliable nano-dot arrays, the method has the defect of insufficient sensitivity.

Disclosure of Invention

In view of this, an object of the embodiments of the present invention is to provide a method for fabricating a SERS substrate by ion implantation, which enhances a raman signal of the substrate and solves a disadvantage that a substrate nanodot array in the prior art is not sensitive enough.

The application provides the following technical scheme through an embodiment:

a method of ion implantation to fabricate a SERS substrate, comprising:

processing the monocrystalline silicon by adopting a plasma immersion ion injection mode to form a nano-pillar array structure on the surface of the monocrystalline silicon;

and (3) evaporating a noble metal film on the surface of the monocrystalline silicon with the nano-pillar array, so that a noble metal nano-point array is formed on the side wall of the nano-pillar array structure, and an SERS substrate is obtained.

Preferably, the obtaining a SERS substrate comprises:

and carrying out He plasma injection on the monocrystalline silicon subjected to the precious metal film evaporation to obtain the SERS substrate.

Preferably, the processing of the monocrystalline silicon by plasma immersion ion implantation comprises:

and processing the monocrystalline silicon by adopting a low-energy plasma immersion ion implantation mode.

Preferably, the height of the nanopillar array structure is 2-2.5 um.

Preferably, the width of the nano-pillar array structure is 300-900 nm.

Preferably, the processing of the monocrystalline silicon by plasma immersion ion implantation comprises:

by using SF₆Gas as etching gas, O₂As a protective gas, single crystal silicon is treated by plasma immersion ion implantation.

Preferably, the depositing a noble metal film on the surface of the single crystal silicon on which the nanopillar array is formed includes:

and evaporating a noble metal film on the surface of the monocrystalline silicon on which the nano-pillar array is formed by adopting an electron beam evaporation mode.

Preferably, the noble metal is gold, silver, copper or platinum.

Preferably, the implantation power for He plasma implantation of the silicon single crystal after deposition of the noble metal film is: 30W-100W.

Preferably, the He plasma implantation time for the single crystal silicon on which the noble metal film is deposited is: 10s-60 s.

The method for manufacturing the SERS substrate by ion implantation provided by the embodiment of the application has at least the following beneficial effects:

according to the invention, the monocrystalline silicon is treated by adopting a plasma immersion ion implantation mode, the implantation area is increased, the monocrystalline silicon with larger size can be treated at one time, and compared with a low-temperature reactive ion etching method, the reactive ion implantation method can be carried out at normal temperature, so that the cost is lower, and the process is simple; and the surface of the monocrystalline silicon is formed into a nano-pillar array structure, so that the surface area is increased, the probability of generating hot spots (enhanced Raman effect hot spots, hereinafter referred to as hot spots) is improved, and Raman signals can be enhanced. The noble metal film is evaporated on the surface of the monocrystalline silicon with the nano-pillar array, so that the area of the noble metal film can be greatly increased. And each nano point in the noble metal nano point array is of a film structure, and the discontinuous nano point array formed by the film structure can form more and uniform hot spots, so that the Raman signal intensity is improved. In conclusion, the SERS substrate manufactured and formed by the invention enhances Raman signals and overcomes the defect that the substrate nanodot array in the prior art is not sensitive enough.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a flow chart of a method for fabricating a SERS substrate by ion implantation according to a preferred embodiment of the present invention;

fig. 2 is a schematic diagram of an exemplary single-crystal silicon structure after step S10 is completed in an example of fabricating a SERS substrate according to a preferred embodiment of the present invention;

fig. 3 is a schematic diagram of an exemplary single-crystal silicon structure before and after He plasma implantation is completed in an example of fabricating a SERS substrate according to a preferred embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

Referring to fig. 1, in the present embodiment, a method for fabricating a SERS substrate by ion implantation is provided, and fig. 1 shows a flowchart of the method, which specifically includes:

step S10: processing the monocrystalline silicon by adopting a plasma immersion ion injection mode to form a nano-pillar array structure on the surface of the monocrystalline silicon;

step S20: and (3) evaporating a noble metal film on the surface of the monocrystalline silicon with the nano-pillar array, so that a noble metal nano-point array is formed on the side wall of the nano-pillar array structure, and an SERS substrate is obtained.

In step S10, the surface of the single crystal silicon may be processed by Plasma Immersion Ion Implantation (PIII). Compared with the method of low-temperature reactive ion etching, the method of plasma immersion ion implantation can be carried out at normal temperature, not only has lower cost, but also has simple process and low cost, and can be used for large-scale batch manufacturing. The energy of the plasma immersion ion implantation may be 100eV to 800eV, and preferably may be 500 eV.

For example: putting an unused N-type high-resistance single-polished silicon wafer into an immersed plasma ion implanter, and adjusting corresponding process conditions to prepare the surface structure of the single-polished silicon wafer; introducing a certain proportion of SF₆(Sulfur hexafluoride)/O₂(oxygen) for ion implantation, wherein, SF₆Gas as etching gas, O₂As a shielding gas; under the action of an electric field, the plasma bombards the surface of the silicon wafer, wherein the bombardment energy can be 500eV, so that the microstructure on the surface of the silicon wafer is reformed, and the micro structure on the surface of the silicon wafer is formedThe appearance and the macroscopic color are changed, and the surface of the silicon chip can have a needle tip array structure, namely a nano-pillar array. At this time, the surface microstructure of the silicon wafer changes, and the reflectivity of the silicon wafer to light changes, so that the surface color of the silicon wafer becomes black. When the introduced SF is present₆And O₂When the flow ratio is changed, the microstructure of the surface of the silicon chip, the sharpness degree of the needle point and the steepness degree of the edge of the needle point are correspondingly changed. Three-dimensional structures of different height-depth ratios can be prepared by varying the gas flow ratio, wherein SF₆The higher the content ratio of (a), the higher the degree of erosion of the surface of the single crystal silicon. The resulting structure is prepared as shown in the cross-sectional and top views of fig. 2.

In step S10, the formed nanopillar array structure may be a wall structure with a high steepness, and the arrangement is orderly, so as to ensure better signal repeatability and stability of the manufactured SERS substrate. Compared with other array structures (such as pyramid structures), the nano-pillar array structure has the advantages that the array is denser, the surface area on the same area size is larger, and more hot spots can be obtained.

Further, since too narrow nano-pillars in the nano-pillar array can cause the noble metal film to be flat and not rough, and too wide can reduce the number of noble metal particles (such as silver particles), too wide and too narrow can cause the number of hot spots to be reduced; therefore, the width of the nano-pillars in this embodiment can be 300-900 nm. The height of the nano-pillar array structure may be 1-3um, but too high may cause the nano-pillars to collapse, too low to meet the requirement of increasing the heat spot, and thus the more preferable height may be 2-2.5 um. The height and width of the nanopillars can be observed and determined by Scanning Electron Microscopy (SEM).

In step S20, one embodiment of the evaporation process may be: and (3) evaporating a noble metal film (namely, forming the noble metal film by dense noble metal nano particles) on the surface of the monocrystalline silicon by adopting an electron beam evaporation mode. The noble metal film is specifically evaporated on the side wall of the nano-pillar. The noble metal in this embodiment may be gold, silver, copper, platinum, etc., without limitation. A high-density nano-dot array can be formed on the side wall of each column body of the nano-column array, and the surface of the monocrystalline silicon subjected to noble metal film evaporation has a strong coupling enhancement effect on a surface local electromagnetic field; compared with a discontinuous noble metal film, the noble metal nanoparticles (such as silver nanoparticles) can form a larger number of hot spots, so that the probability that probe molecules fall into the hot spots is improved, and the sensitivity of the substrate is effectively improved.

Further, the thickness of the noble metal film should be controlled to 10 to 80 nm. It should be noted that, in this embodiment, the reason why the noble metal film is too thin is that the number of noble metal particles is too small, which results in insufficient number of hot spots, the noble metal film is relatively flat, and the raman signal enhancement effect is reduced by reducing the distance between the particles. Therefore, the thickness of the noble metal film (such as a silver film) can be controlled to be 35-45nm in a preferred scheme, and different types of SERS substrates can be manufactured by controlling the thickness of the noble metal film.

In order to further improve the substrate raman signal, in this embodiment, He plasma implantation is further performed on the single crystal silicon after the deposition of the noble metal film in step S20, so as to finally obtain the SERS substrate. As shown in fig. 3, the structure surface of the SERS substrate after re-implantation does not change significantly, but the substrate raman signal is further enhanced.

Specifically, the power of He plasma injection is 30W-100W; further, the He plasma injection time is too long to reach the saturation state, so the injection time can be controlled as follows: 10s-60 s.

In this embodiment, because He ion volume is less, when He plasma is used for injection, the sheath layer formed by the plasma can enter the inside of the nano-column array gap, and when raman signal detection is performed, the surface local electric field between the nano-column arrays can be enhanced along with the irradiation of laser, so that the intensity of the obtained raman signal is improved.

In conclusion, the monocrystalline silicon is processed by adopting the plasma immersion ion implantation mode, the implantation area is increased, the monocrystalline silicon with larger size can be processed at one time, and compared with the method of low-temperature reactive ion etching, the reactive ion implantation method can be carried out at normal temperature, so that the cost is lower, and the process is simple; and the surface area of the nano-pillar array structure formed on the surface of the monocrystalline silicon is increased, the probability of generating hot spots is improved, and Raman signals can be enhanced. The noble metal film is evaporated on the surface of the monocrystalline silicon with the nano-pillar array, so that the area of the noble metal film can be greatly increased. And each nano point in the noble metal nano point array is of a noble metal film structure, and a discontinuous nano point array formed by the film structure can form more and uniform hot spots, so that the Raman signal intensity is improved. He plasma injection is carried out on the monocrystalline silicon after the noble metal film is evaporated, and the SERS substrate is obtained, wherein the local surface electric field of the SERS substrate can be enhanced through the He plasma injection, so that the effect of enhancing Raman signals is achieved. The SERS substrate formed by the invention enhances Raman signals, has better signal repeatability and stability and low manufacturing cost, and can be used for laboratory substance detection and portable Raman detection instruments. The defect that the substrate nano-dot array is not sensitive enough in the prior art is solved.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.