Infrared window structure and preparation method thereof

Abstract

The invention provides an infrared window structure and a preparation method thereof, the infrared window structure comprises a substrate and an antireflection film arranged on one side surface of the substrate, the substrate is a zinc oxide substrate, and the antireflection film is an ytterbium oxide film. According to the invention, the transparent conductive zinc oxide is used for replacing a traditional non-conductive material as a medium-wave infrared window material, and the ytterbium oxide film with a certain thickness is arranged on the surface of the zinc oxide single crystal, so that the transmittance of the zinc oxide single crystal material in medium-wave infrared is improved, and the electromagnetic wave interference resistance of the infrared window material is improved; the application range is widened, and the use performance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of thin film design, and relates to an infrared window structure and a preparation method thereof, and in particular to a medium-wave infrared high-transmittance window structure resistant to electromagnetic wave interference and a preparation method thereof. Background Art

[0002] At present, traditional infrared window materials mainly use non-conductive insulating materials such as ZnS, which cannot effectively resist the passage of electromagnetic waves. In complex and harsh working environments, the practicality will be greatly reduced. With the development of materials science, the growth method of ZnO single crystal materials has made further breakthroughs, making transparent and conductive ZnO expected to replace ZnS and other materials and become a new generation of window materials in the mid-infrared band.

[0003] However, the transmittance of ZnO single crystal materials in the mid-wave infrared band of 3000-5000nm is only greater than 75%, and the research on coating infrared anti-reflection film on ZnO single crystal materials is still in its infancy. Therefore, it is urgent to select suitable materials and preparation methods, combine them with ZnO single crystals, and obtain an infrared window structure to overcome the defects of existing technologies and meet practical application needs. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an infrared window structure and a preparation method thereof. In the present invention, transparent conductive zinc oxide is used instead of traditional non-conductive materials as the window material for medium-wave infrared, and an ytterbium oxide film of a certain thickness is arranged on the surface of the zinc oxide single crystal, thereby improving the transmittance of the zinc oxide single crystal material in the medium-wave infrared, improving the anti-electromagnetic wave interference ability of the infrared window material, broadening the application range, and improving the performance.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides an infrared window structure, comprising a substrate and an anti-reflection film disposed on a surface of one side of the substrate, wherein the substrate is a zinc oxide substrate, and the anti-reflection film is an ytterbium oxide film.

[0007] In the present invention, transparent conductive zinc oxide is used instead of traditional non-conductive materials as the window material for medium-wave infrared, and an ytterbium oxide film of a certain thickness is arranged on the surface of the zinc oxide single crystal, thereby improving the transmittance of the zinc oxide single crystal material in the medium-wave infrared, improving the anti-electromagnetic wave interference ability of the infrared window material, broadening the application range, and improving the performance.

[0008] It should be noted that in the present invention, the zinc oxide substrate is prepared by a hydrothermal growth method, and the ytterbium oxide film is prepared by a magnetron sputtering method.

[0009] It should be noted that traditional infrared window materials have poor electrical conductivity, cannot effectively resist the passage of electromagnetic waves, and have low practicality; and the transmittance of ZnO single crystal materials in the mid-wave infrared band is low. Therefore, the present application invents a substrate and an anti-reflection film deposited on a single side surface of the substrate, and uses transparent conductive ZnO instead of traditional non-conductive materials as the window material for the mid-wave infrared. A magnetron sputtering preparation method is selected to coat a certain thickness of Yb2O3 anti-reflection film on the surface of the ZnO single crystal, thereby improving the transmittance of the ZnO single crystal material in the mid-wave infrared.

[0010] As a preferred technical solution of the present invention, the surface roughness of the substrate is Ra0.006-Ra0.007, for example, it can be Ra0.006, Ra0.0062, Ra0.0064, Ra0.0066, Ra0.0068, Ra0.007, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0011] It should be noted that the present invention does not specifically limit the shape of the substrate, and those skilled in the art can make adaptive adjustments according to actual conditions. Among them, the shape of the substrate can be a rectangle.

[0012] Preferably, the optical thickness of the substrate is 0.18-0.22 mm, for example, 0.18 mm, 0.19 mm, 0.2 mm, 0.21 mm, 0.22 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] The optical thickness of the substrate in the present invention is 0.18 to 0.22 mm because within this size range, the substrate has a smaller self-absorption of mid-wave infrared and a higher transmittance. If it is not within this range, the substrate will have a higher intrinsic absorption rate of mid-wave infrared. This is because the self-absorption effect of the material increases with increasing thickness. The optical thickness of the substrate is 0.18 to 0.22 mm, so that a suitable balance is achieved between the self-absorption effect and the required radiation transmission.

[0014] Preferably, the transmittance of the substrate in the mid-wave infrared band is greater than 75%, for example, it can be 76%, 78%, 80%, 82%, 85%, 86%, 90%, 92%, 95%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] As a preferred technical solution of the present invention, the resistivity of the substrate is less than 100Ω·cm, for example, it can be 99Ω·cm, 98Ω·cm, 95Ω·cm, 90Ω·cm, 86Ω·cm, 87Ω·cm, 80Ω·cm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the carrier concentration of the substrate is less than 5×10 17 cm -3 , for example, it can be 4.9×10 17 cm -3 , 4.8×10 17 cm -3 , 3.5×10 17 cm -3 , 3.2×10 17 cm -3 , 2×10 17 cm -3 , 1.8×10 17 cm -3 The above range is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0017] It should be noted that the carrier concentration of the substrate in the present invention refers to the number of electrons per unit volume of zinc oxide.

[0018] Preferably, the carrier Hall mobility of the substrate is greater than 80 cm 2 ·V -1 ·s -1 , for example, it can be 81cm 2 ·V -1 ·s -1 、83cm 2 ·V -1 ·s -1 、85cm 2 ·V -1 ·s -1 、88cm 2 ·V -1 ·s -1 、90cm 2 ·V -1 ·s -1 、92cm 2 ·V -1 ·s -1 The above range is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0019] It should be noted that the carrier Hall mobility of the substrate in the present invention refers to the migration speed of carriers in zinc oxide under the action of an external magnetic field.

[0020] As a preferred technical solution of the present invention, the optical thickness of the anti-reflection film is 900-1100nm, for example, it can be 900nm, 920nm, 940nm, 960nm, 980nm, 1000nm, 1020nm, 1040nm, 1060nm, 1080nm, 1100nm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] The optical thickness of the anti-reflection film in the present invention is 900-1100nm, because within this size range, the device has an anti-reflection effect on the mid-wave infrared band. If it is not within this range, the device will not be able to enhance the transmittance of the mid-wave infrared. This is because the size range corresponds to a quarter of the mid-wave infrared wavelength. According to the optical principle of the anti-reflection film, the optical path difference reflected on the two surfaces of the film is exactly equal to half a wavelength, thus canceling each other out. This reduces the reflection loss of light and enhances the intensity of the transmitted light.

[0022] Preferably, the refractive index of the antireflection film is 1.5-1.6, for example, it can be 1.5, 1.52, 1.54, 1.56, 1.58, 1.6, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] In a second aspect, the present invention provides a method for preparing the infrared window structure according to the first aspect, the method comprising:

[0024] The antireflection film is magnetron sputtered on the surface of the substrate to obtain an infrared window structure.

[0025] As a preferred technical solution of the present invention, the magnetron sputtering is carried out in the following manner:

[0026] Ytterbium oxide is used as a target source and argon gas is used as a discharge gas to deposit an ytterbium oxide film on the substrate.

[0027] It should be noted that the present invention uses argon because argon is an inert gas, so it will not chemically react with the target material or the base material during magnetron sputtering; in magnetron sputtering, argon is used to generate plasma. Plasma is generated by discharging argon gas, and its presence helps to dissociate the target material from the target and release it into the air in the form of atoms or ions, which are then deposited on the base material. The presence of this plasma makes the sputtering process more efficient; the use of argon can also help control the gas pressure in the sputtering chamber. By adjusting the flow rate of argon gas, the required working gas pressure can be maintained to ensure that the film preparation process is carried out in a stable environment.

[0028] Preferably, the power source for magnetron sputtering is a radio frequency power source.

[0029] It should be noted that the radio frequency power supply in the present invention refers to a power supply used to generate radio frequency electric power, and its output is generally a sine wave or a pulse, which is well known to those skilled in the art.

[0030] Preferably, the output power of the magnetron sputtering power supply is 50-60W, for example, it can be 50W, 52W, 54W, 56W, 58W, 60W, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the gas flow rate of the argon gas is 50-60m 3 / min, for example, it can be 50m 3 / min、52m 3 / min、54m 3 / min、56m 3 / min、58m 3 / min、60m 3 / min, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] The output power of the magnetron sputtering power supply is 50-60W and the gas flow rate of argon gas is 50-60m 3 / min, because within this range the quality of the grown ytterbium oxide film can meet the requirements for achieving anti-reflection. If it is not within this range, it will lead to poor or no anti-reflection effect. This is because the physical and chemical properties of the ytterbium oxide film are the key to achieving anti-reflection.

[0033] As a preferred technical solution of the present invention, the substrate needs to be double-sided polished before magnetron sputtering.

[0034] Preferably, the double-sided polishing is performed in the following manner:

[0035] The substrate is placed in an ethanol solution for ultrasonic treatment, and then rinsed and dried before double-sided polishing.

[0036] It should be noted that in the present invention, by performing double-sided polishing on the substrate before magnetron sputtering, the substrate's transmittance to mid-wave infrared can be increased, and it is beneficial to the deposition, attachment, and growth of the ytterbium oxide film. If the double-sided polishing is not performed, the substrate will have a large intrinsic absorption of mid-wave infrared, low transmittance, and the grown ytterbium oxide film will be of poor quality, with poor or no anti-reflection effect. Among them, the ethanol solution is used because alcohol solvents generally have good solubility, can effectively dissolve and clean many organic and inorganic substances, and alcohol solvents have high volatility, are easy to evaporate after cleaning, and will not leave obvious watermarks or stains.

[0037] Preferably, the ultrasonic treatment time is 10 to 12 min, for example, it can be 10 min, 10.3 min, 10.6 min, 10.9 min, 11 min, 11.4 min, 11.6 min, 11.8 min, 12 min, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the rinsing treatment uses deionized water.

[0039] Preferably, the drying process uses nitrogen drying.

[0040] As a preferred technical solution of the present invention, the substrate needs to be heated before magnetron sputtering.

[0041] Preferably, the heating treatment is performed in the following manner:

[0042] The substrate was placed on a rotating heating stage for heating.

[0043] It should be noted that the present invention does not specifically limit the specific shape, model, material, etc. of the rotary heating table. Those skilled in the art should know that the rotary heating table can be used during magnetron sputtering operations.

[0044] Preferably, the temperature of the heating treatment is 80-90°C, for example, 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the heating treatment time is 10 to 12 minutes, for example, it can be 10 minutes, 10.3 minutes, 10.6 minutes, 10.9 minutes, 11 minutes, 11.4 minutes, 11.6 minutes, 11.8 minutes, 12 minutes, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] The heating treatment time in the present invention is 10 to 12 minutes and the temperature is 80 to 90° C., because within this range, the thickness and quality of the grown ytterbium oxide film can achieve the effect of anti-reflection. If it is not within this range, it will lead to poor anti-reflection effect or no anti-reflection effect. This is because the physicochemical properties of the ytterbium oxide film, such as thickness, are the key to achieving anti-reflection.

[0047] Preferably, the rotation speed of the rotary heating table is 15-16 r / min, for example, it can be 15 r / min, 15.2 r / min, 15.4 r / min, 15.6 r / min, 15.8 r / min, 16 r / min, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] The rotation speed of the rotary heating stage in the present invention is 15 to 16 r / min because within this range, the deposition, adhesion and growth of the ytterbium oxide film are more uniform. If it is not within this range, the thickness of the ytterbium oxide film will be uneven, reducing the anti-reflection performance of the device. This is because the physicochemical properties of the ytterbium oxide film, such as film thickness and uniformity, are the key to achieving anti-reflection.

[0049] As a preferred technical solution of the present invention, during magnetron sputtering, the minimum linear distance between the substrate and the anti-reflection film is 5 to 6 cm, for example, it can be 5 cm, 5.2 cm, 5.4 cm, 5.6 cm, 5.8 cm, 6 cm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] It should be noted that, in the present invention, the minimum linear distance between the substrate and the antireflection film during magnetron sputtering represents the minimum linear distance between two planes.

[0051] Preferably, the magnetron sputtering is performed after the ytterbium oxide film is glowed, and deposition is performed after the glow is stabilized.

[0052] It should be noted that the term "flashing" in the present invention refers to the bright, visible flash phenomenon that occurs on the target surface when the electron beam or ion beam hits the material target during magnetron sputtering. This flash is usually accompanied by the heating and ionization process of the target surface, generating a high-temperature plasma. The particles in this plasma are focused and accelerated by the magnetic field, and then hit the material target, releasing it and finally depositing it on the substrate.

[0053] Preferably, the waiting time is 5 to 6 minutes, for example, it can be 5 minutes, 5.2 minutes, 5.4 minutes, 5.6 minutes, 5.8 minutes, 6 minutes, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0054] As a preferred technical solution of the present invention, the system vacuum degree before magnetron sputtering is less than 10 -3 Pa, for example, can be 0.8×10 -3 Pa, 0.6×10 -3 Pa, 0.5×10 -3 Pa, 0.4×10 -3 Pa, 0.2×10-3 Pa, etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] Preferably, the system vacuum degree in the magnetron sputtering is 0.8-1Pa, for example, it can be 0.8Pa, 0.84Pa, 0.88Pa, 0.9Pa, 0.92Pa, 0.96Pa, 0.99Pa, 1Pa, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] Preferably, the magnetron sputtering time is 120 to 130 min, for example, it can be 120 min, 122 min, 124 min, 126 min, 128 min, 30 min, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] Preferably, after the magnetron sputtering, the temperature of the substrate is less than 85°C, for example, it can be 84°C, 83°C, 80°C, 76°C, 68°C, 50°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0058] It should be noted that in the present invention, after magnetron sputtering, when the temperature of the substrate is less than 85°C, the rotating heating table is stopped for heating, and the vacuum is broken after the substrate cools down to room temperature. The cooling method can be natural cooling or artificial processing cooling, and the vacuum is broken by slowly filling oxygen to control the pressure of the sampling chamber.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] In the present invention, transparent and conductive zinc oxide is used instead of traditional non-conductive materials as the window material for medium-wave infrared, and a preparation method of magnetron sputtering is selected to plate an ytterbium oxide film of a certain thickness on the surface of the zinc oxide single crystal to reduce light reflection and loss, thereby forming a practical medium-wave infrared high-transmittance window structure that is resistant to electromagnetic interference, greatly improving the ability of the infrared window material to resist electromagnetic interference, broadening the scope of application, and improving the performance of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 A schematic diagram of an infrared window structure provided for a specific embodiment of the present invention;

[0062] Figure 2 A transmittance diagram of the zinc oxide substrate in the infrared window structure provided in Comparative Example 1 in the mid-wave infrared band;

[0063] Figure 3 A transmittance diagram of the infrared window structure provided in Example 1 in the mid-wave infrared band;

[0064] Figure 4 A comparison chart of the transmittance of the zinc oxide substrate and the infrared window structure provided in Comparative Example 1 and Example 1;

[0065] Among them, 1-substrate; 2-antireflection film. DETAILED DESCRIPTION

[0066] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0067] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0068] Those skilled in the art should understand that the present invention necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main inventive point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0069] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0070] In a specific embodiment, the present invention provides an infrared window structure such as Figure 1 As shown, the infrared window structure includes a substrate 1 and an anti-reflection film 2 arranged on one side surface of the substrate 1, the substrate 1 is a zinc oxide substrate 1, and the anti-reflection film 2 is an ytterbium oxide film.

[0071] It should be noted that traditional infrared window materials have poor electrical conductivity, cannot effectively prevent the passage of electromagnetic waves, and have low practicality; and the transmittance of ZnO single crystal materials in the mid-wave infrared band is low. Therefore, the present application invents a substrate 1 and an anti-reflection film 2 deposited on a single side surface of the substrate 1, and uses transparent conductive ZnO instead of traditional non-conductive materials as the window material for the mid-wave infrared. A magnetron sputtering preparation method is selected to coat a certain thickness of Yb2O3 anti-reflection film 2 on the surface of the ZnO single crystal, thereby improving the transmittance of the ZnO single crystal material in the mid-wave infrared.

[0072] Further, the surface roughness of the substrate 1 is Ra0.006-Ra0.007, for example, it can be Ra0.006, Ra0.0062, Ra0.0064, Ra0.0066, Ra0.0068, Ra0.007, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable. It should be noted that the present invention does not specifically limit the shape of the substrate 1, and those skilled in the art can make adaptive adjustments according to actual conditions. Among them, the shape of the substrate 1 can be a rectangle.

[0073] Furthermore, the optical thickness of the substrate 1 is 0.18-0.22 mm, for example, 0.18 mm, 0.19 mm, 0.2 mm, 0.21 mm, 0.22 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0074] Furthermore, the transmittance of the substrate 1 in the mid-wave infrared band is greater than 75%, for example, it can be 76%, 78%, 80%, 82%, 85%, 86%, 90%, 92%, 95%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0075] Furthermore, the resistivity of the substrate 1 is less than 100Ω·cm, for example, it can be 99Ω·cm, 98Ω·cm, 95Ω·cm, 90Ω·cm, 86Ω·cm, 87Ω·cm, 80Ω·cm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0076] Furthermore, the carrier concentration of the substrate 1 is less than 5×10 17 cm -3 , for example, it can be 4.9×10 17 cm -3 , 4.8×10 17 cm -3 , 3.5×10 17 cm -3 , 3.2×10 17 cm -3 , 2×1017 cm -3 , 1.8×10 17 cm -3 The above range is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0077] Furthermore, the carrier Hall mobility of the substrate 1 is greater than 80 cm 2 ·V -1 ·s -1 , for example, it can be 81cm 2 ·V -1 ·s -1 、83cm 2 ·V -1 ·s -1 、85cm 2 ·V -1 ·s -1 、88cm 2 ·V -1 ·s -1 、90cm 2 ·V -1 ·s -1 、92cm 2 ·V -1 ·s -1 The above range is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0078] Furthermore, the optical thickness of the anti-reflection film 2 is 900-1100 nm, for example, it can be 900 nm, 920 nm, 940 nm, 960 nm, 980 nm, 1000 nm, 1020 nm, 1040 nm, 1060 nm, 1080 nm, 1100 nm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0079] Furthermore, the refractive index of the antireflection film 2 is 1.5-1.6, for example, it can be 1.5, 1.52, 1.54, 1.56, 1.58, 1.6, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0080] In another specific embodiment, the present invention provides a method for preparing the above-mentioned infrared window structure, comprising:

[0081] An antireflection film 2 is magnetron sputtered on the surface of a substrate 1 to obtain an infrared window structure.

[0082] Furthermore, magnetron sputtering is performed in the following manner: using ytterbium oxide as a target source and argon as a discharge gas, an ytterbium oxide film is deposited on the substrate 1 .

[0083] Furthermore, the power source of magnetron sputtering adopts a radio frequency power source. It should be noted that the radio frequency power source in the present invention refers to a power source used to generate radio frequency electric power, and its output is generally a sine wave or a pulse, which is well known to those skilled in the art.

[0084] Furthermore, the output power of the magnetron sputtering power supply is 50-60W, for example, it can be 50W, 52W, 54W, 56W, 58W, 60W, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0085] Furthermore, the gas flow rate of argon gas is 50-60m 3 / min, for example, it can be 50m 3 / min、52m 3 / min、54m 3 / min、56m 3 / min、58m 3 / min、60m 3 / min, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0086] Furthermore, the substrate 1 needs to be double-sided polished before magnetron sputtering. The double-sided polishing is performed in the following manner: the substrate 1 is placed in an ethanol solution for ultrasonic treatment, and then rinsed and dried to complete the double-sided polishing.

[0087] Furthermore, the time of ultrasonic treatment is 10 to 12 min, for example, it can be 10 min, 10.3 min, 10.6 min, 10.9 min, 11 min, 11.4 min, 11.6 min, 11.8 min, 12 min, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0088] Furthermore, the rinsing treatment uses deionized water for rinsing, and the drying treatment uses nitrogen for drying.

[0089] Furthermore, the substrate 1 needs to be heated before magnetron sputtering, and the heating treatment is performed in the following manner: the substrate 1 is placed on a rotating heating table for heating. It should be noted that the specific shape, model, material, etc. of the rotating heating table are not particularly limited in the present invention, and those skilled in the art should know that the rotating heating table can be used during magnetron sputtering operation.

[0090] Furthermore, the temperature of the heating treatment is 80-90°C, for example, it can be 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0091] Furthermore, the heating treatment time is 10 to 12 minutes, for example, it can be 10 minutes, 10.3 minutes, 10.6 minutes, 10.9 minutes, 11 minutes, 11.4 minutes, 11.6 minutes, 11.8 minutes, 12 minutes, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0092] Furthermore, the rotation speed of the rotary heating table is 15-16 r / min, for example, it can be 15 r / min, 15.2 r / min, 15.4 r / min, 15.6 r / min, 15.8 r / min, 16 r / min, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0093] Furthermore, during magnetron sputtering, the minimum linear distance between the substrate 1 and the anti-reflection film 2 is 5 to 6 cm, for example, 5 cm, 5.2 cm, 5.4 cm, 5.6 cm, 5.8 cm, 6 cm, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable. It should be noted that in the present invention, the minimum linear distance between the substrate 1 and the anti-reflection film 2 during magnetron sputtering represents the minimum linear distance between two planes.

[0094] Furthermore, the magnetron sputtering waits after the ytterbium oxide film glows, and then deposits after the glow stabilizes. The waiting time is 5 to 6 minutes, for example, 5 minutes, 5.2 minutes, 5.4 minutes, 5.6 minutes, 5.8 minutes, 6 minutes, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0095] Furthermore, the system vacuum degree before magnetron sputtering is less than 10 -3 Pa, for example, can be 0.8×10 -3 Pa, 0.6×10 -3 Pa, 0.5×10 -3 Pa, 0.4×10 -3 Pa, 0.2×10 -3 Pa, etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0096] Furthermore, the system vacuum degree in magnetron sputtering is 0.8-1Pa, for example, it can be 0.8Pa, 0.84Pa, 0.88Pa, 0.9Pa, 0.92Pa, 0.96Pa, 0.99Pa, 1Pa, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0097] Furthermore, the time of magnetron sputtering is 120 to 130 minutes, for example, it can be 120 minutes, 122 minutes, 124 minutes, 126 minutes, 128 minutes, 30 minutes, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0098] Further, after magnetron sputtering, the temperature of the substrate 1 is less than 85°C, for example, it can be 84°C, 83°C, 80°C, 76°C, 68°C, 50°C, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. It should be noted that in the present invention, after magnetron sputtering, the temperature of the substrate 1 is less than 85°C, the rotating heating table is stopped for heating, and the vacuum is broken after the substrate 1 is cooled to room temperature. The cooling method can be self-cooling or artificial processing cooling.

[0099] Example 1

[0100] This embodiment provides an infrared window structure and a method for manufacturing the same, wherein:

[0101] The infrared window structure comprises a substrate 1 and an anti-reflection film 2 arranged on a surface of one side of the substrate 1. The substrate 1 is a zinc oxide substrate 1, and the anti-reflection film 2 is an ytterbium oxide film.

[0102] The substrate 1 is double-sided polished and has a surface roughness of Ra0.006. The optical thickness of the substrate 1 is 0.18 mm. The transmittance of the substrate 1 in the mid-wave infrared band is 80%. The resistivity of the substrate 1 is 95 Ω·cm. The carrier concentration of the substrate 1 is 4.8×10 17 cm -3 The carrier Hall mobility of substrate 1 is 81 cm 2 ·V -1 ·s -1 .

[0103] The optical thickness of the antireflection film 2 is 900 nm, and the refractive index of the antireflection film 2 is 1.5.

[0104] The preparation method of the infrared window structure comprises:

[0105] An antireflection film 2 is magnetron sputtered on the surface of a substrate 1 to obtain an infrared window structure.

[0106] The magnetron sputtering is performed in the following manner: ytterbium oxide is used as a target source, argon gas is used as a discharge gas, and an ytterbium oxide film is deposited on the substrate 1. The power supply of the magnetron sputtering is a radio frequency power supply. The output power of the power supply of the magnetron sputtering is 50W; the gas flow rate of the argon gas is 50m 3 / min.

[0107] Before magnetron sputtering, the substrate 1 needs to be double-sided polished. The double-sided polishing is performed in the following manner: the substrate 1 is placed in an ethanol solution for ultrasonic treatment, and then the double-sided polishing is completed after rinsing and drying. The ultrasonic treatment time is 10 minutes, the rinsing treatment is rinsed with deionized water, and the drying treatment is dried with nitrogen.

[0108] The substrate 1 needs to be heated before magnetron sputtering, and the heating treatment is performed in the following manner: the substrate 1 is placed on a rotating heating table for heating at a temperature of 80° C., a heating time of 10 min, and a rotating speed of 15 r / min.

[0109] During magnetron sputtering, the minimum linear distance between the substrate 1 and the antireflection film 2 is 5 cm. The magnetron sputtering waits after the ytterbium oxide film glows, and then deposits after the glow stabilizes. The waiting time is 5 minutes, and the system vacuum before magnetron sputtering is 0.9×10 -3 Pa, the system vacuum degree during magnetron sputtering was 0.8 Pa, the magnetron sputtering time was 120 min, and after magnetron sputtering, the temperature of the substrate 1 was 80° C.

[0110] Example 2

[0111] This embodiment provides an infrared window structure and a method for preparing the same, which is different from Embodiment 1 in that:

[0112] The substrate 1 is double-sided polished and has a surface roughness of Ra0.007. The optical thickness of the substrate 1 is 0.22 mm. The transmittance of the substrate 1 in the mid-wave infrared band is 60%. The resistivity of the substrate 1 is 80 Ω·cm. The carrier concentration of the substrate 1 is 3×10 17 cm -3 The carrier Hall mobility of substrate 1 is 95 cm 2 ·V -1 ·s -1 .

[0113] The optical thickness of the antireflection film 2 is 1100 nm, and the refractive index of the antireflection film 2 is 1.6.

[0114] The preparation method of the infrared window structure comprises:

[0115] The output power of the magnetron sputtering power supply is 60W; the gas flow rate of argon is 50m 3 / min.

[0116] The ultrasonic treatment time was 12 min.

[0117] The temperature of the heating treatment is 90° C., the time of the heating treatment is 12 min, and the rotation speed of the rotary heating table is 16 r / min.

[0118] During magnetron sputtering, the minimum linear distance between the substrate 1 and the antireflection film 2 is 6 cm. The magnetron sputtering waits after the ytterbium oxide film glows, and then deposits after the glow stabilizes. The waiting time is 6 minutes, and the system vacuum before magnetron sputtering is 0.6×10 -3 Pa, the system vacuum degree in magnetron sputtering is 1 Pa, the magnetron sputtering time is 130 min, and after magnetron sputtering, the temperature of the substrate 1 is 50° C.

[0119] Other parameters and experimental conditions are the same as those in Example 1.

[0120] Comparative Example 1

[0121] This comparative example provides an infrared window structure, which is different from Example 1 in that no antireflection film 2 is provided, and other parameters and experimental conditions are the same as those of Example 1.

[0122] Comparative Example 2

[0123] This comparative example provides an infrared window structure, which is different from Example 1 in that the antireflection film 2 is an aluminum oxide film, and the other parameters and experimental conditions are the same as those of Example 1.

[0124] The infrared window structures in the above embodiments and comparative examples were tested for transmittance in the mid-wave infrared band. The specific testing method included testing the transmittance of the zinc oxide substrate, the zinc oxide coated with ytterbium oxide film, and the zinc oxide coated with aluminum oxide film in the mid-wave infrared band, using a Fourier transform infrared spectrometer. The results are as follows:

[0125] Depend on Figure 2 It can be seen that the dotted line is the atmospheric background, and the solid line indicates that the transmittance of the zinc oxide substrate is 87% to 78% in the mid-wave infrared band of 3000nm to 5000nm.

[0126] Depend on Figure 3 It can be seen that the dotted line is the atmospheric background, and the solid line shows that the transmittance of the zinc oxide substrate coated with ytterbium oxide is 94% to 81% in the mid-wave infrared band of 3000nm to 5000nm.

[0127] Depend on Figure 4 It can be seen that the dotted line is the transmittance of the zinc oxide substrate in the mid-wave infrared band of 3000nm to 5000nm, and the solid line is the transmittance of the zinc oxide substrate coated with ytterbium oxide in the mid-wave infrared band of 3000nm to 5000nm. The transmittance of the zinc oxide substrate coated with ytterbium oxide is significantly improved.

[0128] In summary, the present invention uses transparent conductive zinc oxide instead of traditional non-conductive materials as the window material for medium-wave infrared, and arranges an ytterbium oxide film of a certain thickness on the surface of the zinc oxide single crystal, thereby improving the transmittance of the zinc oxide single crystal material in the medium-wave infrared, improving the anti-electromagnetic interference ability of the infrared window material, broadening the application range, and improving the performance.

[0129] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. An infrared window structure, characterized in that: The infrared window structure comprises a substrate and an anti-reflection film arranged on a surface of one side of the substrate; The substrate is a zinc oxide substrate, and the anti-reflection film is an ytterbium oxide film.

2. The infrared window structure according to claim 1, characterized in that: The surface roughness of the substrate is Ra0.006-Ra0.007; Preferably, the optical thickness of the substrate is 0.18 to 0.22 mm; Preferably, the transmittance of the substrate in the mid-wave infrared band is greater than 75%.

3. The infrared window structure according to claim 1 or 2, characterized in that: The resistivity of the substrate is less than 100 Ω·cm; Preferably, the carrier concentration of the substrate is less than 5×10 17 cm -3 ; Preferably, the carrier Hall mobility of the substrate is greater than 80 cm 2 ·V -1 ·s -1 .

4. The infrared window structure according to any one of claims 1 to 3, characterized in that: The optical thickness of the antireflection film is 900-1100 nm; Preferably, the refractive index of the antireflection film is 1.5-1.

6.

5. A method for preparing the infrared window structure according to any one of claims 1 to 4, characterized in that: The preparation method comprises: The antireflection film is magnetron sputtered on the surface of the substrate to obtain an infrared window structure.

6. The preparation method according to claim 5, characterized in that: The magnetron sputtering is carried out in the following manner: Using ytterbium oxide as a target source and argon as a discharge gas, an ytterbium oxide film is deposited on the substrate; Preferably, the power source for magnetron sputtering is a radio frequency power source; Preferably, the output power of the magnetron sputtering power supply is 50-60W; Preferably, the gas flow rate of the argon gas is 50-60m 3 / min.

7. The preparation method according to claim 5 or 6, characterized in that: The substrate needs to be double-sided polished before magnetron sputtering; Preferably, the double-sided polishing is performed in the following manner: The substrate is placed in an ethanol solution for ultrasonic treatment, and then rinsed and dried before double-sided polishing. Preferably, the ultrasonic treatment time is 10 to 12 minutes; Preferably, the rinsing treatment uses deionized water for rinsing; Preferably, the drying process uses nitrogen drying.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The substrate needs to be heated before magnetron sputtering; Preferably, the heating treatment is performed in the following manner: placing the substrate on a rotating heating table for heating; Preferably, the temperature of the heating treatment is 80-90°C; Preferably, the heating treatment time is 10 to 12 minutes; Preferably, the rotation speed of the rotary heating table is 15-16 r / min.

9. The preparation method according to any one of claims 5 to 8, characterized in that: During magnetron sputtering, the minimum linear distance between the substrate and the antireflection film is 5 to 6 cm; Preferably, the magnetron sputtering is performed after the ytterbium oxide film glows, and deposition is performed after the glow stabilizes; Preferably, the waiting time is 5 to 6 minutes.

10. The preparation method according to any one of claims 5 to 9, characterized in that: The system vacuum degree before magnetron sputtering is less than 10 -3 Pa; Preferably, the system vacuum degree in the magnetron sputtering is 0.8-1 Pa; Preferably, the magnetron sputtering time is 120 to 130 minutes; Preferably, after the magnetron sputtering, the temperature of the substrate is less than 85°C.

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