Gold-silver core-shell nanosphere array preparation method and gold-silver core-shell nanosphere array

Abstract

The present invention relates to the field of semiconductor technology, and in particular to a method for preparing a gold-silver core-shell nanosphere array and a gold-silver core-shell nanosphere array. The method comprises first forming a gold disk array on a substrate surface, forming a gold ball array after a first annealing treatment, and then forming a silver film on the gold ball and the substrate surface. Through a second annealing treatment, the adhesion between the gold ball and the substrate decreases, causing the gold ball to loosen on the substrate. Due to the effect of the temperature field and thermal stress, the silver film deposited on the substrate surface will periodically break and condense toward the gold ball with the gold ball as the center. As the condensation proceeds, the silver film at the substrate and the gold ball will continuously squeeze the gold ball, so that silver enters between the gold ball and the substrate, and connects together, thereby forming a gold-silver core-shell nanosphere array with good periodic arrangement. The present invention reduces the use of chemical reagents, has little damage to the environment, keeps the substrate intact, does not affect the performance of power devices, has a simple preparation process, and is conducive to large-scale production.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for preparing a gold-silver core-shell nanosphere array and the gold-silver core-shell nanosphere array. Background Art

[0002] Periodically arranged precious metal nanomaterials, such as gold, silver, platinum, palladium, etc., are widely used due to their surface enhanced Raman scattering (SERS) effect. Compared with single metal nanomaterials, bimetallic nanoarrays with synergistic effects can have very excellent optical, electrical, thermal, magnetic and other physical effects by changing the core-shell type, density, shell thickness, etc. The core-shell nanostructure composed of gold with excellent stability and silver with high sensitivity can change the plasma resonance absorption peak of the material and can be widely used in micro-nano gratings, photoelectric catalysis and biosensor chips.

[0003] However, the current gold-silver core-shell nanomaterials are mainly synthesized by wet chemical methods. This preparation method uses a large amount of chemical reagents and is prone to cause significant pollution to the environment. In addition, the arrangement period of the gold-silver core-shell nanomaterials synthesized by wet chemical methods on the substrate is very poor, which will have a great impact on the performance of the device. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing a gold-silver core-shell nanosphere array and a gold-silver core-shell nanosphere array.

[0005] To achieve the above object, the present invention provides a method for preparing a gold-silver core-shell nanosphere array, comprising:

[0006] Providing a substrate, and forming a gold disk array on the surface of the substrate;

[0007] Performing a first annealing treatment on the substrate having the gold disk array so that the gold disk array is condensed into a gold ball array;

[0008] forming a silver film on the surface of the substrate having the gold ball array;

[0009] The substrate with the silver film is subjected to a second annealing treatment, the temperature of the second annealing treatment being lower than that of the first annealing treatment, so that the silver film shrinks inward and condenses into a silver shell on the surface of the gold ball array, thereby forming a periodically arranged gold-silver core-shell nanosphere array.

[0010] Optionally, the diameter of the gold disks of the gold disk array is in the range of 300nm to 350nm, and the period of the circular hole array is in the range of 600nm to 650nm.

[0011] Optionally, the heating rate range of the first annealing treatment is 100°C min -1~120℃min -1 The temperature range of the first annealing treatment is 600° C. to 650° C., and the holding time range of the first annealing treatment is 60 min to 80 min.

[0012] Optionally, the thickness of the silver film is in the range of 10 nm to 20 nm, and the deposition rate of the silver film is in the range of

[0013] Optionally, the heating rate range of the second annealing treatment is 100°C min -1 ~120℃min -1 The temperature range of the second annealing treatment is 400° C. to 450° C., and the holding time range of the second annealing treatment is 180 min to 240 min.

[0014] Optionally, the radius of the gold balls of the gold ball array is in the range of 40nm to 50nm, and the period of the gold ball array is in the range of 700nm to 750nm.

[0015] Optionally, the step of forming a gold disk array on the substrate surface includes:

[0016] Providing a photoresist layer substrate having a circular hole array pattern on its surface, wherein the photoresist layer is formed with a circular hole array region and a mask region, the circular hole array region has a circular hole bottom and a circular hole sidewall, and the circular hole bottom has no photoresist;

[0017] forming a gold film on the surfaces of the circular hole array region and the mask region;

[0018] The photoresist layer is used as a mask, and the gold film on the side wall of the circular hole and the gold film in the mask area are removed by oblique etching, and the gold film on the bottom of the circular hole is retained;

[0019] After removing the photoresist in the mask area, a gold disk array is obtained.

[0020] The present invention also provides a gold-silver core-shell nanosphere array, which is prepared by using the above-mentioned method for preparing a gold-silver core-shell nanosphere array.

[0021] Optionally, the radius of the gold-silver core-shell nanospheres of the gold-silver core-shell nanosphere array is in the range of 60nm to 70nm, and the period of the gold-silver core-shell nanosphere array is in the range of 700nm to 750nm.

[0022] In summary, the advantages and beneficial effects of the present invention are:

[0023] The present invention provides a method for preparing a gold-silver core-shell nanosphere array, comprising forming a gold disk array on the surface of a substrate; subjecting the substrate having the gold disk array to a first annealing treatment, so that the gold disk array is condensed into a gold sphere array; forming a silver film on the surface of the substrate having the gold sphere array; subjecting the substrate having the silver film to a second annealing treatment, so that the silver film is inwardly shrunk and condensed into a silver shell on the surface of the gold sphere array, and finally obtaining a gold-silver core-shell nanosphere array.

[0024] The present invention uses a first annealing treatment to condense the gold disk array into a gold ball array, and then uses a second annealing treatment to wrap the silver film on the surface of the gold ball. During the second annealing treatment, the adhesion between the gold ball and the substrate decreases, causing the gold ball to loosen on the substrate. Due to the effect of the temperature field and thermal stress, the silver film deposited on the surface of the substrate will periodically break and condense toward the gold ball with the gold ball as the center. As the condensation proceeds, the silver film at the substrate and the gold ball will continuously squeeze the gold ball, so that the gold ball with low adhesion is separated from the substrate, and then the silver enters between the gold ball and the substrate. As the heating proceeds, the silver film entering between the gold ball and the substrate is connected together, and the silver film is redistributed on the surface of the gold ball, thereby forming a gold-silver core-shell nanosphere array with good periodic arrangement.

[0025] The physical method of the present invention forms the gold-silver core-shell nanosphere array, reduces the use of chemical reagents, has little damage to the environment, and the produced gold-silver core-shell nanosphere array has good periodicity, the substrate remains intact, and the performance of the prepared power device is ensured not to be affected. The preparation process of the gold-silver core-shell nanosphere array is simple to operate, which is conducive to large-scale batch production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of a process for preparing a gold-silver core-shell nanosphere array provided in an embodiment of the present invention;

[0027] Figures 2 to 8 A schematic diagram of a method for preparing a gold-silver core-shell nanosphere array provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to facilitate understanding by those skilled in the art, the present invention will be further described in detail below with reference to specific embodiments.

[0029] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0030] The present invention provides a method for preparing a gold-silver core-shell nanosphere array. Figure 1 As shown, including:

[0031] Step S10, providing a substrate, and forming a gold disk array on the surface of the substrate;

[0032] Step S20, performing a first annealing treatment on the substrate having the gold disk array, so that the gold disk array is condensed into a gold ball array;

[0033] Step S30, forming a silver film on the surface of the substrate having the gold ball array;

[0034] Step S40, subjecting the substrate with the silver film to a second annealing treatment, wherein the second annealing treatment is performed at a temperature lower than that of the first annealing treatment, so that the silver film shrinks inward and condenses into a silver shell on the surface of the gold ball array, thereby forming a periodically arranged gold-silver core-shell nanosphere array.

[0035] Specifically, execute step S10, please refer to Figure 2 to Figure 5 , providing a substrate 10, and forming a gold disk array 40 on the surface of the substrate 10.

[0036] In an embodiment of the present invention, the substrate 10 is a 4-inch glass substrate 10. In other embodiments, the substrate is a silicon substrate, a silicon carbide substrate, a sapphire substrate or other suitable substrates.

[0037] In the embodiment of the present invention, the provided substrate 10 is further cleaned by ultrasonically cleaning the substrate 10 in acetone, ethanol and deionized water for 30 minutes to 40 minutes respectively to remove the particulate impurities and organic matter remaining on the surface of the substrate 10.

[0038] In the embodiment of the present invention, the step of forming the gold disk array 40 on the surface of the substrate 10 includes:

[0039] Step S11, providing a photoresist layer substrate having a circular hole array pattern on its surface, wherein the photoresist layer is formed with a circular hole array region and a mask region, the circular hole array region has a circular hole bottom and a circular hole sidewall, and the circular hole bottom has no photoresist;

[0040] In an embodiment of the present invention, the steps of forming a photoresist layer substrate 10 having a circular hole array pattern include:

[0041] Spin-coat a photoresist 20 of a certain thickness on the surface of the substrate 10 using a coating machine;

[0042] Using a mask plate with a circular hole array to cover the photoresist 20 on the surface of the substrate 10;

[0043] The photoresist 20 is etched to transfer the circular hole array pattern of the mask plate to the photoresist 20, so that the photoresist 20 forms a photoresist layer 30 with a circular hole array, wherein the photoresist layer 30 is formed with a circular hole array area and a mask area, the circular hole array area has a circular hole bottom and a circular hole sidewall, and the circular hole bottom has no photoresist.

[0044] In the embodiment of the present invention, the rotation rate of the spin-coated photoresist ranges from 2000 rpm to 3000 rpm.

[0045] In the embodiment of the present invention, the temperature range of the photoresist curing is 80° C. to 90° C., and the time range of the photoresist curing is 5 min to 10 min.

[0046] In the embodiment of the present invention, the light intensity of the exposure process performed on the photoresist ranges from 1.8 mW / cm2 to 2.0 mW / cm2, and the exposure process time ranges from 20s to 23s.

[0047] In the embodiment of the present invention, the thickness of the photoresist layer 20 with the circular hole array is in the range of 300 nm to 350 nm. Specifically, the thickness of the photoresist layer 20 with the circular hole array is 325 nm.

[0048] The hole depth of the circular hole array formed on the surface of the substrate 10 is in the range of 450nm to 500nm, the hole diameter of the circular hole array is in the range of 300nm to 350nm, and the period of the circular hole array is in the range of 600nm to 650nm.

[0049] In the embodiment of the present invention, the hole depth of the circular hole array formed on the surface of the substrate 10 is 500 nm, the hole diameter of the circular hole array is 300 nm, and the period of the circular hole array is 600 nm.

[0050] Since the circular holes of the photoresist layer 20 with the circular hole array are distributed periodically, the subsequently formed gold disk array and the gold ball array obtained after the first annealing treatment both have good periodicity, so that the final gold-silver core-shell nanosphere array has good periodicity.

[0051] The size of the circular hole array in the photoresist layer 20 is determined according to the size of the gold ball array. The size of the circular hole array affects the size of the formed gold disk array, and the size of the gold disk array affects the size of the gold ball array.

[0052] Step S12, please refer to Figure 4 , forming a gold film on the surfaces of the circular hole array region and the mask region;

[0053] In the embodiment of the present invention, the thickness of the gold film 30 is 5 nm.

[0054] In the embodiment of the present invention, a gold film 30 is deposited on the surface of the circular hole array region and the mask region by electron beam evaporation, and the rate range of the electron beam evaporation is

[0055] In other embodiments, a gold film is formed on the surface of the circular hole array region and the mask region by a magnetron sputtering method, and the sputtering rate of the magnetron sputtering is in the range of The thickness of the gold film 30 is in the range of 5 nm to 10 nm.

[0056] Step S13, using the photoresist layer as a mask, obliquely etching to remove the gold film on the sidewall of the circular hole and the gold film in the mask area, and retaining the gold film on the bottom of the circular hole;

[0057] After the gold film on the circular hole sidewall and the gold film in the mask area are removed by oblique etching, the gold film on the circular hole bottom in the circular hole array area is separated from the gold film on the circular hole sidewall. When the photoresist layer is subsequently peeled off, the gold film on the circular hole bottom will not be damaged, thereby obtaining a complete gold circular disk array.

[0058] In an embodiment of the present invention, the substrate 10 with the gold film 30 formed on the surface is placed in an oxygen plasma stripper to remove the photoresist layer 20. The time range for removing the photoresist layer 20 is 10 min to 15 min. The concentration range of oxygen in the process of removing the photoresist layer 20 is 200 sccm to 300 sccm. The power range of the process of removing the photoresist layer 20 is 400 W to 500 W.

[0059] In the embodiment of the present invention, the time for removing the photoresist layer 20 is 15 minutes, the concentration of oxygen during the process of removing the photoresist layer 20 is 300 sccm, and the power during the process of removing the photoresist layer 20 is 500 W.

[0060] Step S14, please refer to Figure 5 After removing the photoresist in the mask area, a gold disk array 40 is obtained.

[0061] Execute step S20, please refer to Figure 6 , the substrate 10 having the gold disk array 40 is subjected to a first annealing treatment, so that the gold disk array 40 is condensed into a gold ball array 50 .

[0062] The radius of the obtained gold ball array 50 is in the range of 40 nm to 50 nm, and the period of the gold ball array 50 is in the range of 700 nm to 750 nm.

[0063] In the embodiment of the present invention, the radius of the obtained gold ball array 50 is 44 nm, and the period range of the gold ball array 50 is 700 nm.

[0064] In the embodiment of the present invention, the substrate 10 having the gold disk array 50 is subjected to a first annealing treatment in an annealing furnace. The heating rate of the first annealing treatment is in the range of 100°C min -1 ~120℃min -1 The temperature range of the first annealing treatment is 600°C to 650°C, the holding time range of the first annealing treatment is 60min to 80min, the temperature of the first annealing treatment reaches the thermal activation temperature of gold, and is kept for a period of time, so that the gold disk array 50 is condensed into a gold ball array.

[0065] In the embodiment of the present invention, the heating rate of the first annealing treatment is 100°C min -1 The temperature of the first annealing treatment is 600° C., and the holding time range of the first annealing treatment is 60 minutes.

[0066] Execute step S30, please refer to Figure 7 , a silver film 60 is formed on the surface of the substrate 10 having the gold ball array.

[0067] In the embodiment of the present invention, the thickness of the silver film 60 is in the range of 10 nm to 20 nm, and the deposition rate of the silver film 60 is in the range of Avoid the silver film 60 being too thick so that the silver film cannot break, and avoid the silver film being too thin so that the silver film cannot completely cover the gold ball.

[0068] In the embodiment of the present invention, the thickness of the silver film 60 is 20 nm, and the deposition rate of the silver film 60 is

[0069] By means of an atomic layer deposition (ALD) method, a silver film 60 is deposited on the surface where the gold ball array 50 is formed and the surface of the substrate 10. By means of atomic layer deposition, ALD can generate a thin film that is closely attached to the gold balls, and the deposited silver film 60 is accurate to the atomic scale, and the thickness of the formed silver film 60 is more uniform.

[0070] Execute step S40, please refer to Figure 8 The substrate 10 with the silver film 60 is subjected to a second annealing treatment, the temperature of the second annealing treatment being lower than that of the first annealing treatment, so that the silver film 60 shrinks inward and condenses into a silver shell 70 on the surface of the gold ball array, thereby forming a periodically arranged gold-silver core-shell nanosphere array.

[0071] In the embodiment of the present invention, the substrate 10 deposited with the silver film is subjected to a second annealing treatment in an annealing furnace, and the heating rate of the second annealing treatment is in the range of 100°C min -1 ~120℃min -1 The temperature range of the second annealing treatment is 400° C. to 450° C., and the holding time range of the second annealing treatment is 180 min to 240 min.

[0072] In the embodiment of the present invention, the heating rate in the second annealing furnace is 100°C min -1 The temperature of the second annealing treatment is 400° C., and the holding time range of the second annealing treatment is 180 minutes.

[0073] The silver film is subjected to a second annealing treatment at a temperature of 400° C., and the adhesion between the gold ball and the substrate 10 is reduced without affecting the shape of the gold ball that has been formed, so that the gold ball is loosened on the glass sheet. During the second annealing treatment, due to the effects of the temperature field and thermal stress, the silver film deposited on the surface of the substrate 10 will periodically break and condense toward the gold ball with the gold ball as the center. As the condensation proceeds, the silver film at the substrate 10 and the gold ball will continuously squeeze the gold ball, so that the gold ball with lower adhesion is separated from the substrate 10, and then the silver enters between the gold ball and the substrate 10. As the heating proceeds, the silver film that enters between the gold ball and the substrate 10 is connected together; and under the action of thermal stress, the surface energy of the silver film that becomes a core-shell is the lowest, so that the silver film is redistributed on the surface of the gold ball, thereby forming a well-periodically arranged gold-silver core-shell nanosphere array.

[0074] The embodiment of the present invention further provides a gold-silver core-shell nanosphere array, which is prepared by the above-mentioned method for preparing a gold-silver core-shell nanosphere array.

[0075] In the embodiment of the present invention, the radius range of the gold-silver core-shell nanosphere array is 60nm-70nm, and the period range of the gold-silver core-shell nanosphere array is 700nm-750nm.

[0076] Finally, it is to be noted that any modification or equivalent replacement of part or all of the technical features based on the device structure of the present invention and the technical solution of the described embodiment, which does not deviate from the essence of the corresponding technical solution of the present invention, belongs to the patent scope of the device structure of the present invention and the described implementation scheme.

Claims

1. A method for preparing a gold-silver core-shell nanosphere array, characterized in that: include: Providing a substrate, and forming a gold disk array on the surface of the substrate; The substrate having the gold disk array is subjected to a first annealing treatment, so that the gold disk array is condensed into a gold ball array, and the heating rate range of the first annealing treatment is 100° C. min -1 ~120℃ min -1 , the temperature range of the first annealing treatment is 600° C. to 650° C., and the holding time range of the first annealing treatment is 60 min to 80 min; forming a silver film on the surface of the substrate having the gold ball array; The substrate with the silver film is subjected to a second annealing treatment, the temperature of the second annealing treatment being lower than that of the first annealing treatment, so that the silver film shrinks inward and condenses into a silver shell on the surface of the gold ball array, thereby forming a periodically arranged gold-silver core-shell nanosphere array.

2. A method for preparing a gold-silver core-shell nanosphere array as claimed in claim 1, characterized in that: The thickness of the silver film is in the range of 10 nm to 20 nm, and the deposition rate of the silver film is in the range of 5 Å s -1 ~10Å s -1 .

3. The method for preparing a gold-silver core-shell nanosphere array according to claim 1, characterized in that: The heating rate range of the second annealing treatment is 100°C min -1 ~120℃ min -1 The temperature range of the second annealing treatment is 400°C~450°C, and the holding time range of the second annealing treatment is 180min~240min.

4. A method for preparing a gold-silver core-shell nanosphere array as claimed in claim 1, characterized in that: The radius of the gold balls of the gold ball array is in the range of 40nm to 50nm, and the period of the gold ball array is in the range of 700nm to 750nm.

5. The method for preparing a gold-silver core-shell nanosphere array according to claim 1, characterized in that: The step of forming a gold disk array on the substrate surface comprises: Providing a photoresist layer substrate having a circular hole array pattern on its surface, wherein the photoresist layer is formed with a circular hole array region and a mask region, the circular hole array region has a circular hole bottom and a circular hole sidewall, and the circular hole bottom has no photoresist; forming a gold film on the surfaces of the circular hole array region and the mask region; The photoresist layer is used as a mask, and the gold film on the side wall of the circular hole and the gold film in the mask area are removed by oblique etching, and the gold film on the bottom of the circular hole is retained; After removing the photoresist in the mask area, a gold disk array is obtained.

6. A method for preparing a gold-silver core-shell nanosphere array as claimed in claim 5, characterized in that: The diameter of the gold disks of the gold disk array ranges from 300nm to 350nm, and the period of the circular hole array ranges from 600nm to 650nm.

7. A method for preparing a gold-silver core-shell nanosphere array as claimed in claim 1, characterized in that: The radius of the gold-silver core-shell nanospheres of the gold-silver core-shell nanosphere array is in the range of 60nm to 70nm, and the period of the gold-silver core-shell nanosphere array is in the range of 700nm to 750nm.

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