Aperiodic film for X-ray focusing and preparation method thereof
By adopting the non-periodic magnetron sputtering technology of Si/B4C/W film units in X-ray focusing applications, the thickness control and deposition accuracy problems are solved, the X-ray reflection efficiency and structural stability are improved, and the long-term work is met need.
Patent Information
- Application Number
- CN202411216641.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-02
- Publication Date
- 2024-12-10
AI Technical Summary
In X-ray focusing applications, existing non-periodic films have difficulties in thickness control accuracy, insufficient deposition accuracy and poor radiation resistance, which affect the reflection efficiency and the need for long-term work.
Using Si/B4C/W film units, the Si layer, B4C layer and W layer are sequentially plated on the curved substrate by aperiodic magnetron sputtering technology to form an aperiodic multi-layer film structure, and the thickness of the W layer is controlled from bottom to top. Increment and heat treatment is performed to improve structural stability.
It achieves higher X-ray reflection efficiency, reaching more than 50%, meeting the needs of long-term work, and maintaining surface-shaped accuracy on the curved substrate, improving focus accuracy and reflection effect.
Smart Images
Figure CN119108124A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of optical elements, and in particular relates to a non-periodic film for X-ray focusing and a preparation method thereof. Background Art
[0002] At present, in the field of X-rays, when focusing the incident light, the optical elements that can be selected include capillaries, zone plates, KB mirrors, and various aspherical mirror systems. Each optical element has its own advantages and disadvantages. For example, the advantage of capillaries is that they can be made very small and do not take up space. However, the receiving surface and angle of the incident light are relatively low. Zone plates can focus X-rays to a very small size, but are only suitable for transmission. The reflective focusing optical elements are mainly KB mirrors, Montel mirrors, spherical mirrors, parabolic mirrors, etc. Focusing X-rays not only depends on the curved surface shape of the optical element, but also depends on the reflective film coated on the surface, so as to enhance the reflection flux of X-rays and achieve a monochromatic effect. Therefore, for the Montel curved focusing mirror, the non-periodic thin film technology on its surface has very important optical application value and application prospects.
[0003] The non-periodic film applied to the Montel curved focusing mirror is not an ordinary linear non-periodic film, but a non-linear non-periodic film. The non-periodic films currently obtained in China have the following defects and problems: First: the difficulty in controlling the thickness accuracy of the non-periodic film. The thickness of the non-periodic film is variable, and the thickness of each layer is different. Within a specific large range of variation values, the thickness accuracy is difficult to control and is required to reach the level of 0.1nm. Second: the deposition accuracy of the non-periodic film at different positions on the curved substrate. Since the film needs to be deposited on a curved surface, especially a parabolic surface, different thicknesses of reflective films need to be deposited at different positions during deposition. At present, there are still deficiencies in the deposition accuracy of the curved surface in China, which is bound to affect the reflection efficiency of the film. Third: Due to the need to reflect high-intensity X-rays for a long time, many X-ray films currently experience stress changes and element diffusion at the interface, resulting in changes in the film structure, drift of the diffraction energy point, poor radiation resistance, and failure to meet the requirements of long-term work. Summary of the invention
[0004] The object of the present invention is to provide a non-periodic film for X-ray focusing and a preparation method thereof. The non-periodic film provided by the present invention has better reflection efficiency for X-rays.
[0005] In order to achieve the above object, the present invention provides the following technical solutions:
[0006] The present invention provides a non-periodic film for X-ray focusing, comprising a plurality of Si / B 4 C / W thin film unit;
[0007] Each Si / B 4 The C / W thin film unit includes a Si layer, a B 4 C layer and W layer; the plurality of Si / B 4 The C / W film unit is a non-periodic multilayer film structure;
[0008] Each Si / B 4 B in C / W film unit 4 The thickness of the C layer is the same; each Si / B 4 The thickness of the Si layer in the C / W thin film unit is the same; each Si / B 4 The thickness of the W layer in the C / W film unit increases from bottom to top.
[0009] Preferably, the multiple Si / B 4 The number of cycles of the C / W film unit is 15 to 25.
[0010] Preferably, the multiple Si / B 4 Each Si / B 4 The total thickness of the C / W thin film unit is 5 to 7.8 nm.
[0011] Preferably, the B 4 The thickness of the C layer is 0.1 to 0.3 nm.
[0012] Preferably, the thickness of the Si layer is 2.5-4.5 nm.
[0013] Preferably, the multiple Si / B 4 The C / W thin film unit consists of three Si / B 4 C / W combination unit, respectively, the first Si / B 4 C / W combination unit, second Si / B 4 C / W combination unit and third Si / B 4 C / W combination unit;
[0014] The first Si / B 4 The number of cycles of the C / W combination unit is 5 to 7; the first Si / B 4 In the C / W combination unit, the thickness difference of the W layer in two adjacent periods is 0.1-0.2 nm;
[0015] The second Si / B 4 The number of cycles of the C / W combination unit is 4 to 6; the second Si / B 4 In the C / W combination unit, the thickness difference of the W layer in two adjacent periods is 0.1 to 0.14 nm; the first Si / B 4The W layer in the last cycle of the C / W combination unit and the second Si / B 4 The thickness difference of the W layer in the first period of the C / W combination unit is 0.1 to 0.14 nm;
[0016] The third Si / B 4 The number of cycles of the C / W combination unit is 7 to 9; the third Si / B 4 In the C / W combination unit, the thickness difference of the W layer in two adjacent periods is 0.07-0.09 nm; the second Si / B 4 The W layer in the last cycle of the C / W combination unit and the third Si / B 4 The thickness difference of the W layer in the first period of the C / W combination unit is 0.07-0.09 nm.
[0017] The present invention also provides a method for preparing the non-periodic film described in the above technical solution, comprising the following steps:
[0018] With W target, B 4 C target and Si target are used as target materials, and Si layer, B 4 The C layer and the W layer are heat treated to obtain the non-periodic film.
[0019] Preferably, the magnetron sputtering conditions include: using argon as the working gas; the sputtering pressure is 0.24-0.28 torr; the sputtering power of the W target is 256-266 W, and the sputtering voltage is 335-345 V; B 4 The sputtering power of the C target is 314-324 W, and the sputtering voltage is 258-268 V; the sputtering power of the Si target is 215-225 W, and the sputtering voltage is 270-290 V; the rotation rate of the sample stage is 150-180 rpm.
[0020] Preferably, the heat treatment temperature is 200-300° C., and the insulation time is 30-60 min.
[0021] The present invention provides a non-periodic film for X-ray focusing, comprising a plurality of Si / B 4 C / W thin film unit; each Si / B 4 The C / W thin film unit includes a Si layer, a B 4 C layer and W layer; the plurality of Si / B 4 The C / W film unit is a non-periodic multilayer film structure; each Si / B 4 B in C / W film unit 4 The thickness of the C layer is the same; each Si / B 4 The thickness of the Si layer in the C / W thin film unit is the same; each Si / B 4The thickness of the W layer in the C / W film unit increases from bottom to top. 4 C / W non-periodic film has better structural stability and can meet the needs of long-term operation. When applied to the surface of Montel mirror, it has strong X-ray reflection ability and the reflection efficiency reaches more than 50%. It can be used in optical elements for focusing X-rays.
[0022] The present invention also provides a method for preparing the non-periodic thin film described in the above technical solution. The present invention accurately coats the non-periodic thin film on the curved substrate under a limited coating process, so that the surface accuracy of the curved substrate is still guaranteed after coating, thereby effectively reflecting the incident X-rays and achieving the designed focusing accuracy and effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 is a SEM image of the non-periodic film obtained in Example 1;
[0024] Figure 2 Four groups of W layers with different ratios were selected as the diffraction result comparison diagrams of multilayer films;
[0025] Figure 3 The theoretical calculation diagram of the diffraction curve when the W layer thickness is 1.78nm;
[0026] Figure 4 This is the theoretical calculation diagram of the diffraction curve when the W layer thickness gradually changes to 3.77nm. DETAILED DESCRIPTION
[0027] The present invention provides a non-periodic film for X-ray focusing, comprising a plurality of Si / B 4 C / W thin film unit;
[0028] Each Si / B 4 The C / W thin film unit includes a Si layer, a B 4 C layer and W layer; the plurality of Si / B 4 The C / W film unit is a non-periodic multilayer film structure;
[0029] Each Si / B 4 B in C / W film unit 4 The thickness of the C layer is the same; each Si / B 4 The thickness of the Si layer in the C / W thin film unit is the same; each Si / B 4 The thickness of the W layer in the C / W film unit increases from bottom to top.
[0030] In the present invention, the plurality of Si / B 4The number of cycles of the C / W thin film unit is preferably 15-25, more preferably 18-22, and even more preferably 19-20.
[0031] In the present invention, the plurality of Si / B 4 Each Si / B 4 The total thickness of the C / W thin film unit is preferably 5 to 7.8 nm.
[0032] In the present invention, the B 4 The thickness of the C layer is preferably 0.1 to 0.3 nm, more preferably 0.2 nm. In the present invention, the thickness of the Si layer is preferably 2.5 to 4.5 nm, more preferably 3.69 nm.
[0033] In the present invention, the plurality of Si / B 4 The C / W thin film unit preferably includes three Si / B 4 C / W combination unit, respectively, the first Si / B 4 C / W combination unit, second Si / B 4 C / W combination unit and third Si / B 4 C / W combination unit.
[0034] In the present invention, the first Si / B 4 The number of cycles of the C / W combination unit is preferably 5 to 7, and more preferably 6; 4 In the C / W combination unit, the difference in thickness of the W layer between two adjacent periods is preferably 0.1 to 0.2 nm, more preferably 0.15 nm.
[0035] In the present invention, the second Si / B 4 The number of cycles of the C / W combination unit is preferably 4 to 6, and more preferably 5; 4 In the C / W combination unit, the thickness difference of the W layer in two adjacent periods is preferably 0.1 to 0.14 nm, and more preferably 0.12 to 0.13 nm; 4 The W layer in the last cycle of the C / W combination unit and the second Si / B 4 The thickness difference of the W layer in the first period of the C / W combination unit is preferably 0.1 to 0.14 nm, more preferably 0.12 to 0.13 nm.
[0036] In the present invention, the third Si / B 4 The number of cycles of the C / W combination unit is preferably 7 to 9, and more preferably 8; 4In the C / W combination unit, the thickness difference of the W layer in two adjacent periods is preferably 0.07-0.09 nm, more preferably 0.08 nm; the second Si / B 4 The W layer in the last cycle of the C / W combination unit and the third Si / B 4 The thickness difference of the W layer in the first period of the C / W combination unit is preferably 0.07 to 0.09 nm, more preferably 0.08 nm.
[0037] The present invention also provides a method for preparing the non-periodic film described in the above technical solution, comprising the following steps:
[0038] With W target, B 4 C target and Si target are used as target materials, and Si layer, B 4 The C layer and the W layer are heat treated to obtain the non-periodic film.
[0039] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well known to those skilled in the art.
[0040] In the present invention, the curved substrate preferably includes single-sided or double-sided polished single crystal silicon, quartz single crystal, fused quartz glass or K9 glass. Before the magnetron sputtering, the present invention also preferably includes cleaning the curved substrate, and the cleaning process preferably includes: ultrasonic cleaning in RCA solution and deionized water in sequence; ultrasonic cleaning in RCA solution to thoroughly clean particles and dust of different sizes attached to the surface of the substrate.
[0041] In the present invention, the magnetron sputtering conditions include: preferably argon is used as the working gas; the sputtering pressure is preferably 0.24-0.28 torr, more preferably 0.26 torr; the sputtering power of the W target is preferably 256-266 W, and the sputtering voltage is preferably 335-345 V; B 4 The sputtering power of the C target is preferably 314-324W, and the sputtering voltage is preferably 258-268V; the sputtering power of the Si target is preferably 215-225W, and the sputtering voltage is preferably 270-290V; the rotation rate of the sample stage is preferably 150-180rpm, and more preferably 160-170rpm. The present invention controls the sputtering power of each target material, thereby regulating the sputtering rate of each target material, thereby ensuring uniform thickness of the sputtered film.
[0042] In the present invention, the temperature of the heat treatment is preferably 200-300° C., and the holding time is preferably 30-60 min.
[0043] In order to further illustrate the present invention, a non-periodic film for X-ray focusing and a preparation method thereof provided by the present invention are described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0044] Example 1
[0045] The curved single crystal silicon substrate is mounted on the corresponding fixture and placed on the sample running carriage in the ultra-high vacuum magnetron sputtering coating machine.
[0046] The vacuum chamber was evacuated to a high vacuum of more than 1E-4Pa, and the sample was rotated simultaneously during the target scanning process at a rotation speed of 180rpm.
[0047] Plating multiple Si / B 4 C / W film, with argon as the working gas, sputtering pressure of 0.25torr, sputtering power of W target of 260W, sputtering voltage of 340V; B 4 The sputtering power of C is 319W, and the sputtering voltage is 263V; the sputtering power of Si target is 220W, and the sputtering voltage is 280V;
[0048] The sputtering cycle is 19, and in each cycle, the Si layer and B 4 The thickness of the C layer and the W layer are shown in Table 1:
[0049] Table 1 Si layer, B in each cycle 4 Thickness of C and W layers
[0050]
[0051]
[0052] After the plating is completed, a heat treatment is performed at 250° C. and the temperature is kept for 30 minutes to obtain the non-periodic thin film.
[0053] Performance Testing
[0054] Figure 1 is the SEM image of the non-periodic film obtained in Example 1. Figure 1 It can be seen that the entire non-periodic film has a clear interface, neat and sharp edges, and no trace of mutual diffusion between the two materials. The thickness of the W layer increases as it moves away from the substrate, forming a non-periodic sandwich structure.
[0055] Figure 2 Four groups of different proportions of W layers were selected as the diffraction results of multilayer films for comparison. It can be seen that the film effect of different W layers is that the reflectivity is different. The W layer has a greater impact on the actual reflectivity, and the other layer materials are relatively less sensitive.
[0056] Figure 3 The theoretical calculation diagram of the diffraction curve when the W layer thickness is 1.78nm (corresponding to the diffraction angle of 0.79°) is shown in Figure 2. Figure 3 It can be seen that the highest reflection efficiency has exceeded 80%;
[0057] Figure 4 The theoretical calculation diagram of the diffraction curve when the thickness of the W layer gradually changes to 3.77nm (corresponding to a diffraction angle of 0.63°). Figure 4 It can be seen that the reflection efficiency is about 80%, and the diffraction angle is reduced compared to the incident angle of the thinner W layer.
[0058] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A non-periodic film for X-ray focusing, characterized in that: Includes multiple Si / B4C / W thin film units; Each Si / B4C / W thin film unit comprises a Si layer, a B4C layer and a W layer stacked in sequence; the plurality of Si / B4C / W thin film units are a non-periodic multilayer film structure; The thickness of the B4C layer in each Si / B4C / W thin film unit is the same; the thickness of the Si layer in each Si / B4C / W thin film unit is the same; the thickness of the W layer in each Si / B4C / W thin film unit increases from bottom to top.
2. The preparation method according to claim 1, characterized in that: The number of cycles of the plurality of Si / B4C / W thin film units is 15-25.
3. The preparation method according to claim 1 or 2, characterized in that: The total thickness of each Si / B4C / W thin film unit in the plurality of Si / B4C / W thin film units is 5 to 7.8 nm.
4. The preparation method according to claim 3, characterized in that: The thickness of the B4C layer is 0.1-0.3 nm.
5. The preparation method according to claim 3, characterized in that: The thickness of the Si layer is 2.5-4.5 nm.
6. The preparation method according to claim 3, characterized in that: The plurality of Si / B4C / W thin film units include three Si / B4C / W combination units from bottom to top, namely a first Si / B4C / W combination unit, a second Si / B4C / W combination unit and a third Si / B4C / W combination unit; The number of periods of the first Si / B4C / W combination unit is 5 to 7; in the first Si / B4C / W combination unit, the thickness difference of the W layer in two adjacent periods is 0.1 to 0.2 nm; The number of periods of the second Si / B4C / W combination unit is 4 to 6; in the second Si / B4C / W combination unit, the thickness difference of the W layer in two adjacent periods is 0.1 to 0.14 nm; the thickness difference of the W layer in the last period of the first Si / B4C / W combination unit and the W layer in the first period of the second Si / B4C / W combination unit is 0.1 to 0.14 nm; The number of periods of the third Si / B4C / W combination unit is 7 to 9; in the third Si / B4C / W combination unit, the thickness difference of the W layer in two adjacent periods is 0.07 to 0.09 nm; the thickness difference between the W layer in the last period of the second Si / B4C / W combination unit and the W layer in the first period of the third Si / B4C / W combination unit is 0.07 to 0.09 nm.
7. The method for preparing a non-periodic thin film according to any one of claims 1 to 6, characterized in that: The following steps are involved: With W target, B4C target and Si target as target materials, Si layer, B4C layer and W layer are sequentially non-periodic magnetron sputtered on a curved substrate, and the non-periodic film is obtained after heat treatment.
8. The preparation method according to claim 7, characterized in that: The conditions of the magnetron sputtering include: argon is used as the working gas; the sputtering gas pressure is 0.24-0.28 torr; the sputtering power of the W target is 256-266 W, and the sputtering voltage is 335-345 V; the sputtering power of the B4C target is 314-324 W, and the sputtering voltage is 258-268 V; the sputtering power of the Si target is 215-225 W, and the sputtering voltage is 270-290 V; the rotation rate of the sample stage is 150-180 rpm.
9. The preparation method according to claim 1, characterized in that: The heat treatment temperature is 200-300° C., and the heat preservation time is 30-60 minutes.