A non-aluminum-based deep ultraviolet polarizing reflector and its preparation method

Abstract

The present invention belongs to the technical field of polarizing reflectors and provides a non-aluminum-based deep ultraviolet polarizing reflector and a preparation method thereof. The non-aluminum-based deep ultraviolet polarizing reflector of the present invention can have good polarization reflection efficiency for incident deep ultraviolet light within the range of 100nm to 300nm. In particular, at 240nm, the S-light reflectivity is 71%, the P-light reflectivity is 15%, and the reflectivity ratio of S-polarized light to P-polarized light reaches 4.7. In this way, during the process of polarizing or analyzing the incident light, only 2 to 3 reflections are required to obtain very pure S-polarized light. This greatly reduces the difficulty of the optical path modulation system, simplifies the optical path system, and reduces the system hardware cost. At the same time, it can ensure that the reflector has a relatively high reflectivity, improve the signal-to-noise ratio and the application efficiency of the detection system.

Description

Technical Field

[0001] The present invention relates to the technical field of polarizing reflectors, and in particular to a non-aluminum-based deep ultraviolet polarizing reflector and a preparation method thereof. Background Art

[0002] Wavelengths of 220nm to 350nm (corresponding to energies of 3.5eV to 5eV) belong to the deep ultraviolet (DUV) band. Due to its higher energy than visible light, DUV is widely used in sterilization, water purification, medical treatment, high-density optical recording, and the decomposition of hazardous substances. For example, UV light with a wavelength of 250nm to 280nm is most effective for direct sterilization; UV light with a wavelength of 270nm to 320nm is most effective for decomposing hazardous substances such as dioxins. Furthermore, a large number of DUV LEDs are used as light sources in various fields. In spectral analysis, light-modulated reflectance spectroscopy allows non-destructive testing of samples with high sensitivity and resolution. This modulation process inevitably requires the use of a large number of DUV reflectors. In some special cases, polarization-modulated DUV reflectors are used. This technique utilizes a large number of reflectors, and certain samples or specialized conditions require obtaining high reflectivity of S- or P-polarized light. Therefore, it is necessary to polarization-modulate the DUV reflectors to obtain relatively single S- or P-polarized light. Conventional modulated deep ultraviolet light provides better clarity, thereby improving the signal-to-noise ratio.

[0003] Al coatings are typically used in the deep UV band. Most deep UV reflectors on the market are made by coating Al metal films on quartz substrates. While this coating offers high reflection efficiency, its single-layer structure makes it difficult to achieve good polarization. In other words, the reflectivity of S and P light is similar, preventing a high degree of separation. This makes it difficult to polarize or analyze incident deep UV wavelength light. This is possible only if multiple mirrors are combined, but this inevitably increases the complexity of the optical system and the optical path alignment. Furthermore, the intensity of the emitted light decreases after multiple reflections. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a non-aluminum-based deep ultraviolet polarizing reflector and a preparation method thereof. The non-aluminum-based deep ultraviolet polarizing reflector provided by the present invention has excellent polarization effect.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a non-aluminum-based deep ultraviolet polarized reflector, comprising a primer layer and a multi-periodic FeO / Co / Ni layer sequentially stacked on a substrate;

[0007] The multi-periodic FeO / Co / Ni layer includes a plurality of stacked single-periodic FeO / Co / Ni layers;

[0008] The single-period FeO / Co / Ni layer includes an FeO layer, a Co layer and a Ni layer stacked in sequence;

[0009] The FeO layer in the single-period FeO / Co / Ni layer is in contact with the base layer.

[0010] Preferably, in the single-period FeO / Co / Ni layer, the thickness of the FeO layer is 12-14 nm, the thickness of the Co layer is 2-3 nm, and the thickness of the Ni layer is 8-10 nm.

[0011] Preferably, the number of periods of the multi-periodic FeO / Co / Ni layer is 50-100.

[0012] Preferably, the multi-periodic FeO / Co / Ni layer is replaced by a multi-periodic Fe2O3 / Co / Ni layer; the number of periods of the multi-periodic Fe2O3 / Co / Ni layer is 50 to 100.

[0013] Preferably, in the single-period Fe2O3 / Co / Ni layer, the thickness of the Fe2O3 layer is 12-14 nm, the thickness of the Co layer is 2-3 nm, and the thickness of the Ni layer is 8-10 nm.

[0014] Preferably, the base layer is made of Ni; and the thickness of the base layer is 1-2 nm.

[0015] Preferably, the substrate is silicon wafer, quartz, fused quartz or K9 glass.

[0016] The present invention also provides a method for preparing the non-aluminum-based deep ultraviolet polarizing reflector described in the above technical solution, comprising the following steps:

[0017] preparing a primer layer on a substrate;

[0018] Sequentially preparing an FeO layer, a Co layer, and a Ni layer on the primer layer, and repeating the process of sequentially preparing the FeO layer, the Co layer, and the Ni layer to obtain a reflector precursor;

[0019] heat-treating the reflector precursor to obtain the non-aluminum-based deep ultraviolet polarized reflector;

[0020] Alternatively, the preparation of the FeO layer is replaced by the preparation of the Fe2O3 layer.

[0021] Preferably, the preparation method of the FeO layer is a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the FeO layer include: the target material is a ferrous oxide target, the power is 240-245W, the voltage is 256-260V, and the time is 16-18 seconds;

[0022] The preparation method of the Fe2O3 layer is a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the Fe2O3 layer include: the target material is a ferric oxide target, the power is 246-250W, the voltage is 260-265V, and the time is 16-18 seconds;

[0023] The preparation method of the Co layer is a DC magnetron sputtering method. The magnetron sputtering parameters of the Co layer include: the target material is a cobalt target, the power is 200-210W, the voltage is 232-240V, and the time is 4-5 seconds:

[0024] The Ni layer is prepared by a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the Ni layer include: a nickel target, a power of 300-310W, a voltage of 364-370V, and a time of 10-12 seconds.

[0025] Preferably, the heat treatment temperature is 80-150° C., and the time is 5-10 minutes.

[0026] The present invention provides a non-aluminum-based deep ultraviolet polarizing reflector, comprising a base layer and a multi-periodic FeO / Co / Ni layer sequentially stacked on a substrate; the multi-periodic FeO / Co / Ni layer comprises a plurality of stacked single-periodic FeO / Co / Ni layers; the single-periodic FeO / Co / Ni layer comprises a FeO layer, a Co layer, and a Ni layer stacked sequentially; and the FeO layer in the single-periodic FeO / Co / Ni layer contacts the base layer. The non-aluminum-based deep ultraviolet polarizing reflector can achieve good polarization reflection efficiency for incident deep ultraviolet light within a range of 100 nm to 300 nm. In particular, at 240 nm, the S-light reflectivity is 71%, the P-light reflectivity is 15%, and the reflectivity ratio of S-polarized light to P-polarized light reaches 4.7. Thus, during polarization or polarization analysis of incident light, only two to three reflections are required to obtain very pure S-polarized light, significantly reducing the difficulty of the optical path modulation system, simplifying the optical path system, and reducing system hardware costs. Furthermore, the reflectivity of the reflector can be ensured to be relatively high, thereby improving the signal-to-noise ratio and the application efficiency of the detection system.

[0027] The present invention also provides a method for preparing the non-aluminum-based deep ultraviolet polarized reflector described in the above technical solution, comprising the following steps: preparing a primer layer on a substrate; sequentially preparing an FeO layer, a Co layer, and a Ni layer on the primer layer, and repeating the process of sequentially preparing the FeO layer, the Co layer, and the Ni layer to obtain a reflector precursor; heat-treating the reflector precursor to obtain the non-aluminum-based deep ultraviolet polarized reflector; or, replacing the FeO layer with an Fe2O3 layer. The preparation method provided by the present invention is simple to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Graph showing the simulated calculation of the light reflectivity of Rs and Rp of the Al-based reflector obtained in Comparative Example 1;

[0029] Figure 2 This is a simulation calculation diagram of the Rs and Rp light reflectivities of the reflector obtained in Example 2. DETAILED DESCRIPTION

[0030] The present invention provides a non-aluminum-based deep ultraviolet polarized reflector, comprising a primer layer and a multi-periodic FeO / Co / Ni layer sequentially stacked on a substrate;

[0031] The multi-periodic FeO / Co / Ni layer includes a plurality of stacked single-periodic FeO / Co / Ni layers;

[0032] The single-period FeO / Co / Ni layer includes an FeO layer, a Co layer and a Ni layer stacked in sequence;

[0033] The FeO layer in the single-period FeO / Co / Ni layer is in contact with the base layer.

[0034] In the present invention, unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0035] The non-aluminum-based deep ultraviolet polarized reflector provided by the present invention includes a substrate. In the present invention, the substrate is preferably a silicon wafer, quartz, fused quartz or K9 glass.

[0036] The non-aluminum-based deep ultraviolet polarizing reflector provided by the present invention includes a base layer stacked on the substrate. In the present invention, the material of the base layer is preferably Ni. In the present invention, the thickness of the base layer is preferably 1 to 2 nm.

[0037] The non-aluminum-based deep ultraviolet polarized reflector provided by the present invention includes a multi-periodic FeO / Co / Ni layer stacked on the base layer. In the present invention, the multi-periodic FeO / Co / Ni layer includes several stacked single-periodic FeO / Co / Ni layers. In the present invention, the number of periods of the multi-periodic FeO / Co / Ni layer is preferably 50 to 100. In the present invention, the single-periodic FeO / Co / Ni layer includes a FeO layer, a Co layer and a Ni layer stacked in sequence. In the present invention, the thickness of the FeO layer in the single-periodic FeO / Co / Ni layer is preferably 12 to 14 nm, specifically preferably 12 nm; the thickness of the Co layer is preferably 2 to 3 nm, specifically preferably 2 nm; the thickness of the Ni layer is preferably 8 to 10 nm, specifically preferably 8 nm. In the present invention, the FeO layer in the single-periodic FeO / Co / Ni layer is in contact with the base layer.

[0038] In the present invention, the multi-periodic FeO / Co / Ni layer is preferably replaced by a multi-periodic Fe2O3 / Co / Ni layer; the number of periods of the multi-periodic Fe2O3 / Co / Ni layer is 50 to 100. In the present invention, the single-periodic Fe2O3 / Co / Ni layer includes a Fe2O3 layer, a Co layer, and a Ni layer stacked in sequence. In the present invention, the thickness of the Fe2O3 layer in the single-periodic Fe2O3 / Co / Ni layer is preferably 12 to 14 nm, the thickness of the Co layer is preferably 2 to 3 nm, and the thickness of the Ni layer is preferably 8 to 10 nm. In the present invention, the Fe2O3 layer in the single-periodic Fe2O3 / Co / Ni layer is in contact with the base layer.

[0039] The present invention also provides a method for preparing the non-aluminum-based deep ultraviolet polarizing reflector described in the above technical solution, comprising the following steps:

[0040] preparing a primer layer on a substrate;

[0041] Sequentially preparing an FeO layer, a Co layer, and a Ni layer on the primer layer, and repeating the process of sequentially preparing the FeO layer, the Co layer, and the Ni layer to obtain a reflector precursor;

[0042] heat-treating the reflector precursor to obtain the non-aluminum-based deep ultraviolet polarized reflector;

[0043] Alternatively, the preparation of the FeO layer is replaced by the preparation of the Fe2O3 layer.

[0044] The present invention prepares a primer layer on a substrate.

[0045] In the present invention, before preparing the primer layer on the substrate, the substrate is preferably cleaned; the cleaning preferably includes a first cleaning and a second cleaning, performed sequentially. The first cleaning agent is preferably an RCA cleaning agent; the second cleaning agent is preferably water, preferably deionized water. In the present invention, both the first cleaning and the second cleaning are preferably performed under ultrasonic conditions. In the present invention, the cleaning can remove organic and inorganic impurities on the substrate.

[0046] In the present invention, the preparation method of the base layer is preferably a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the base layer include: the target material is preferably a nickel target, the power is preferably 300W, the voltage is preferably 364V, and the time is preferably 3 seconds.

[0047] After preparing the base layer, the present invention sequentially prepares an FeO layer, a Co layer and a Ni layer on the base layer, and repeats the process of sequentially preparing the FeO layer, the Co layer and the Ni layer to obtain a reflector precursor.

[0048] In the present invention, the preparation method of the FeO layer is preferably a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the FeO layer include: the target material is preferably a ferrous oxide target, the power is preferably 240-245W, the voltage is preferably 256-260V, and the time is preferably 16-18 seconds.

[0049] In the present invention, the preparation of the FeO layer is replaced by the preparation of the Fe2O3 layer. In the present invention, the preparation method of the Fe2O3 layer is preferably a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the Fe2O3 layer include: the target material is preferably a ferric oxide target, the power is preferably 246-250W, the voltage is preferably 260-265V, and the time is preferably 16-18 seconds.

[0050] In the present invention, the preparation method of the Co layer is preferably a DC magnetron sputtering method, and the magnetron sputtering parameters of the Co layer include: the target material is preferably a cobalt target, the power is preferably 200-210W, the voltage is preferably 232-240V, and the time is preferably 4-5 seconds.

[0051] In the present invention, the preparation method of the Ni layer is preferably a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the Ni layer include: the target material is preferably a nickel target, the power is preferably 300-310W, the voltage is preferably 364-370V, and the time is preferably 10-12 seconds.

[0052] After obtaining the reflector precursor, the present invention performs heat treatment on the reflector precursor to obtain the non-aluminum-based deep ultraviolet polarized reflector.

[0053] In the present invention, the temperature of the heat treatment is preferably 80 to 150° C., and the time is preferably 5 to 10 minutes.

[0054] In the present invention, the heat treatment can remove the stress between the film layers.

[0055] The non-aluminum-based deep ultraviolet polarizing reflector and its preparation method provided by the present invention are described in detail below with reference to the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0056] Example 1

[0057] (1) The silicon wafer is ultrasonically cleaned with RCA cleaning agent and deionized water to ensure that there are no organic and inorganic impurities and set aside.

[0058] (2) A 2 nm thick underlying nickel layer was prepared on the treated substrate. The preparation parameters included: the target material was a nickel target, the power was 300 W, the voltage was 364 V, and the time was 3 seconds.

[0059] (3) A ferrous oxide layer with a thickness of 12 nm was prepared on the underlying nickel layer. The preparation parameters included: the target material was a ferrous oxide target, the power was 240 W, the voltage was 256 V, and the time was 18 seconds.

[0060] (4) A cobalt layer with a thickness of 2 nm was prepared on the ferrous oxide layer. The preparation parameters included: the target material was a cobalt target, the power was 200 W, the voltage was 232 V, and the time was 4 seconds.

[0061] (5) A nickel layer with a thickness of 8 nm was prepared on the cobalt layer. The preparation parameters included: the target material was a nickel target, the power was 300 W, the voltage was 364 V, and the time was 12 seconds.

[0062] Repeat (3)(4)(5) 49 times to obtain a precursor of an iron oxide / cobalt / nickel multilayer structure with 50 cycles;

[0063] (6) The precursor was heat treated at 80°C for 6 min to obtain a non-aluminum-based deep ultraviolet polarized reflector with a period number of 50.

[0064] Example 2

[0065] The difference from Example 1 is that (3)(4)(5) are repeated 99 times in sequence to obtain a non-aluminum-based deep ultraviolet polarizing reflector with a period number of 100.

[0066] Example 3

[0067] The difference from Example 1 is:

[0068] (3) A 12 nm thick iron oxide layer was prepared on the underlying nickel layer. The preparation parameters included: the target material was an iron oxide target, the power was 246 W, the voltage was 260 V, and the time was 18 seconds.

[0069] Example 4

[0070] The difference from Example 3 is that (3)(4)(5) is repeated 99 times in sequence to obtain a non-aluminum-based deep ultraviolet polarizing reflector with a period number of 100.

[0071] Example 5

[0072] The difference from Example 1 is that the heat treatment temperature in (6) is 150°C.

[0073] Comparative Example 1

[0074] An Al-based reflecting mirror comprises a silicon wafer and an aluminum film coated on the silicon wafer, wherein the thickness of the aluminum film is 6nm.

[0075] Based on the reflectivity of extreme ultraviolet light, the reflectivity of S-polarized light, the reflectivity of P-polarized light, and the ratio of the reflection efficiency of the reflectivity of S-polarized light to the reflectivity of P-polarized light at 240 nm of the reflectors obtained in Examples 1 to 5 and Comparative Example 1 were measured. The results are shown in Table 1.

[0076] Table 1 Performance test results of the reflectors obtained in the embodiments and comparative examples

[0077]

[0078] Figure 1 The Rs and Rp light reflectivity simulation calculation diagram of the Al-based reflector obtained in Comparative Example 1 is shown in FIG. Figure 2 The figure is a simulation calculation diagram of the light reflectivity of Rs and Rp of the reflector obtained in Example 2. Figure 1 and 2 It can be seen that although the reflectivity of the Al-based reflector is higher, if a polarizer is made, the reflector provided by the present invention can obtain a better S light and P light suppression ratio, that is, the polarization and analysis efficiency of the reflector provided by the present invention is higher.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A non-aluminum-based deep ultraviolet polarizing reflector, characterized in that: It includes a base layer and a multi-period FeO / Co / Ni layer stacked in sequence on a substrate; The multi-periodic FeO / Co / Ni layer includes a plurality of stacked single-periodic FeO / Co / Ni layers; The single-period FeO / Co / Ni layer includes an FeO layer, a Co layer and a Ni layer stacked in sequence; The FeO layer in the single-period FeO / Co / Ni layer is in contact with the base layer.

2. The non-aluminum-based deep ultraviolet polarizing reflector according to claim 1, characterized in that: In the single-period FeO / Co / Ni layer, the thickness of the FeO layer is 12-14 nm, the thickness of the Co layer is 2-3 nm, and the thickness of the Ni layer is 8-10 nm.

3. The non-aluminum-based deep ultraviolet polarizing reflector according to claim 1 or 2, characterized in that: The number of periods of the multi-periodic FeO / Co / Ni layer is 50-100.

4. The non-aluminum-based deep ultraviolet polarizing reflector according to claim 1, characterized in that: The multi-periodic FeO / Co / Ni layer is replaced by a multi-periodic Fe2O3 / Co / Ni layer; the number of periods of the multi-periodic Fe2O3 / Co / Ni layer is 50 to 100.

5. The non-aluminum-based deep ultraviolet polarizing reflector according to claim 4, characterized in that: In the single-period Fe2O3 / Co / Ni layer, the thickness of the Fe2O3 layer is 12-14 nm, the thickness of the Co layer is 2-3 nm, and the thickness of the Ni layer is 8-10 nm.

6. The non-aluminum-based deep ultraviolet polarizing reflector according to claim 1 or 4, characterized in that: The base layer is made of Ni; the thickness of the base layer is 1-2 nm.

7. The non-aluminum-based deep ultraviolet polarizing reflector according to claim 1 or 4, characterized in that: The substrate is silicon wafer, quartz, fused quartz or K9 glass.

8. The method for preparing the non-aluminum-based deep ultraviolet polarizing reflector according to any one of claims 1 to 7, characterized in that: The following steps are involved: preparing a primer layer on a substrate; Sequentially preparing an FeO layer, a Co layer, and a Ni layer on the primer layer, and repeating the process of sequentially preparing the FeO layer, the Co layer, and the Ni layer to obtain a reflector precursor; heat-treating the reflector precursor to obtain the non-aluminum-based deep ultraviolet polarized reflector; Alternatively, the preparation of the FeO layer is replaced by the preparation of the Fe2O3 layer.

9. The preparation method according to claim 8, characterized in that The preparation method of the FeO layer is a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the FeO layer include: the target material is a ferrous oxide target, the power is 240-245W, the voltage is 256-260V, and the time is 16-18 seconds; The preparation method of the Fe2O3 layer is a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the Fe2O3 layer include: the target material is a ferric oxide target, the power is 246-250W, the voltage is 260-265V, and the time is 16-18 seconds; The preparation method of the Co layer is a DC magnetron sputtering method. The magnetron sputtering parameters of the Co layer include: the target material is a cobalt target, the power is 200-210W, the voltage is 232-240V, and the time is 4-5 seconds: The Ni layer is prepared by a DC magnetron sputtering method, and the DC magnetron sputtering parameters of the Ni layer include: a nickel target, a power of 300-310W, a voltage of 364-370V, and a time of 10-12 seconds.

10. The preparation method according to claim 8, characterized in that The heat treatment temperature is 80-150° C. and the time is 5-10 minutes.

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