Raw material gas pretreatment system and method for preparing CVD ZnSe

Abstract

The invention relates to the technical field of preparation of infrared crystal materials, and particularly provides a feed gas pretreatment system and method for preparing CVD ZnSe. The feed gas pretreatment system for preparing CVD ZnSe comprises a gas grading absorption filtering device, a circulating buffer device and a precision control device which are communicated in sequence, effective filtration and purification of the feed gas before entering the CVD reaction device are ensured, the gas pressure is stabilized through the circular buffer device, and the dynamic balance of the deposition process is maintained through the precise control device.

Description

Technical Field

[0001] The invention relates to the technical field of infrared crystal material preparation, and in particular to a raw material gas pretreatment system and method for preparing CVD ZnSe. Background Art

[0002] CVD ZnSe is an excellent infrared optical material. The current mainstream preparation method is chemical vapor deposition (CVD). This method produces materials with few impurities and dense materials, but it places extremely high demands on the purity of the raw materials zinc and hydrogen selenide. Although the purity of hydrogen selenide gas on the market can reach 99.9%, heavy components and light components are still inevitably present in the gas cylinder. 2 Se will inevitably decompose in trace amounts to produce Se elemental substances. Such impurities will cause defects such as reaction fluctuations, holes, and inclusions during the preparation process. Such defects are close to the wavelength of the transmitted light and will form obvious absorption and scattering effects. Moreover, the shorter the wavelength, the greater the scattering, resulting in a decrease in the transmittance of the material.

[0003] At the same time, affected by the temperature environment and other factors, the gas delivery pressure will also affect the flow stability. The CVD method for preparing ZnSe requires maintaining a stable deposition for dozens of days. Fluctuations in gas purity, pressure and flow during the process will cause the dynamic balance of the deposition process to be broken, and then cause impurities to be generated and stratified, which will greatly affect the optical uniformity of the material and cannot meet the use requirements of lasers and high-resolution imagers.

[0004] Therefore, in view of the above shortcomings, the present invention is specially proposed. Summary of the invention

[0005] The main purpose of the present invention is to propose a raw gas pretreatment system and method for preparing CVD ZnSe. The present invention ensures that the raw gas is effectively filtered and purified before entering the CVD reaction device by sequentially connecting a gas graded absorption filtration device, a circulation buffer device and a precision control device, stabilizes the gas pressure through the circulation buffer device, and maintains the dynamic balance of the deposition process through the precision control device.

[0006] The first aspect of the present invention provides a raw gas pretreatment system for preparing CVD ZnSe, which comprises a gas graded absorption filter device, a circulation buffer device and a precision control device which are connected in sequence; the gas graded absorption filter device is used to connect to an external raw gas source, and the precision control device is used to connect to a CVD reaction device to ensure that the raw gas is effectively filtered and purified before entering the CVD reaction device, and the gas pressure is stabilized by the circulation buffer device, and the dynamic balance of the deposition process is maintained by the precision control device; wherein the raw gas comprises H 2 Se gas.

[0007] In some embodiments of the present invention, the gas grading absorption and filtration device includes a multi-stage filtration device and an adsorption device connected in communication; the multi-stage filtration device is connected to the raw material gas source, and the adsorption device is connected to the circulation buffer device; the multi-stage filtration device is used to filter trace solid particles in the gas, and the adsorption device is used to adsorb small molecule gas impurities.

[0008] In some embodiments of the present invention, the multi-stage filtration device includes a primary filter and a secondary filter connected in series, the primary filter is connected to the raw material gas source, and the secondary filter is connected to the adsorption device.

[0009] In some embodiments of the present invention, the filtration particle size of the primary filter is ≥0.1 μm, and the filtration particle size of the secondary filter is ≥20 nm.

[0010] In some embodiments of the present invention, the filtration particle size of the primary filter is ≥1 μm, and the filtration particle size of the secondary filter is ≥50 nm.

[0011] In some embodiments of the present invention, the primary filter includes one of a stainless steel composite mesh filter element and a quartz filter element; and / or, the secondary filter includes one of carbon nanotubes and a nano filter mesh.

[0012] In some embodiments of the present invention, the adsorption device includes molecular sieve.

[0013] In some embodiments of the present invention, the multi-stage filtration device is arranged in a one-for-one standby mode and is provided with a pressure transducer for pressure monitoring.

[0014] In some embodiments of the present invention, the circulation buffer device includes a primary buffer tank and a secondary buffer tank connected in series, as well as a bypass and a pressure monitor arranged between the primary buffer tank and the secondary buffer tank; the pressure difference between the primary buffer tank and the secondary buffer tank is monitored by the pressure monitor and the pressure is stabilized by circulating buffer through the bypass, and the reflux ratio is 1:4 to 1:7.

[0015] In some embodiments of the present invention, a number of quartz balls or a number of buffer plates are arranged in the primary buffer tank; and / or, a number of laminar flow sheets are arranged in the secondary buffer tank.

[0016] In some embodiments of the present invention, the diameter of the quartz balls is 3 mm to 8 mm.

[0017] In some embodiments of the present invention, the gap between two adjacent laminar flow sheets is 0.3 mm to 1 mm.

[0018] In some embodiments of the present invention, several of the buffer plates are independently erected inside the primary buffer tank and are arranged at intervals along the length direction of the primary buffer tank, and a first gas passage that is communicated is formed between two adjacent buffer plates.

[0019] In some embodiments of the present invention, several of the laminar flow plates are independently arranged horizontally inside the secondary buffer tank and are stacked along the height direction of the secondary buffer tank, and a second gas passage that communicates with the primary buffer tank is formed between two adjacent laminar flow plates.

[0020] In some embodiments of the present invention, the precision control device includes a flow meter and a pressure transmitter that are communicatively connected. The pressure transmitter monitors the pressure change in real time and feeds back a signal to the flow meter to perform micro-dynamic adjustment of the gas flow rate.

[0021] The second aspect of the present invention provides a method for pre-treating a source gas for preparing CVD ZnSe. The source gas pre-treatment method is based on the source gas pre-treatment system described in the first aspect; the source gas pre-treatment method includes: the source gas sequentially passes through a gas grading absorption and filtration device, a circulation buffer device, and a precision control device to ensure effective filtration and purification of the source gas before it enters the CVD reaction device.

[0022] Advantages of the present invention:

[0023] By means of the gas grading absorption and filtration device, the circulation buffer device, and the precision control device that are sequentially communicated, the present invention ensures effective filtration and purification of the source gas before it enters the CVD reaction device, stabilizes the gas pressure through the circulation buffer device, and maintains the dynamic balance during the deposition process through the precision control device.

[0024] The present invention fully filters trace solid impurities in the gas through a multi-stage filtration device, and according to the characteristics of impurities such as oxygen + argon, nitrogen, carbon monoxide, carbon dioxide, total hydrocarbons, hydrogen sulfide, and water in hydrogen selenide, adopts an adsorption method for targeted removal.

[0025] Through the setting of the circulation buffer device, the present invention enables the stable conveying pressure of the gas before it enters the CVD reaction device and avoids fluctuations.

[0026] Through the setting of the precision control device, the present invention uses a mass flow controller to monitor the conveyed mass flow rate in real time. When the mass flow rate fluctuates, dynamic regulation and compensation are implemented to ensure that the actual flow rate remains stable.

[0027] The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specifically illustrates the specific embodiments of the present invention. Brief Description of the Drawings

[0028] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. In the drawings:

[0029] Figure 1 It is a side view of the CVD ZnSe material prepared in the prior art;

[0030] Figure 2 It is a side view of the CVD ZnSe material prepared in the embodiment of the present invention;

[0031] Figure 3 It is a schematic flow chart of the raw material gas pretreatment method for preparing CVD ZnSe in the embodiment of the present invention;

[0032] Figure 4 It is a schematic structural diagram of the raw material gas pretreatment system for preparing CVD ZnSe in the embodiment of the present invention;

[0033] Figure 5 It is a schematic structural diagram of the carbon nanotubes in the embodiment of the present invention;

[0034] Figure 6 It is a schematic structural diagram of the molecular sieve in the embodiment of the present invention;

[0035] Figure 7 It is a schematic structural diagram of the circulation buffer device in some embodiments of the present invention;

[0036] Figure 8 It is a schematic structural diagram of the circulation buffer device in other embodiments of the present invention;

[0037] Figure 9 It is a schematic diagram of the laminated structure of the laminar flow sheet in the buffer tank in the embodiment of the present invention;

[0038] Figure 10 It is a schematic structural diagram of the precision control device in the embodiment of the present invention.

[0039] Reference Signs:

[0040] 100, raw material gas pretreatment system;

[0041] 10. Gas classification absorption and filtration device; 11. Primary filter; 12. Secondary filter; 13. Adsorption device; 130. Molecular sieve;

[0042] 20. Circulation buffer device; 21. Primary buffer tank; 22. Secondary buffer tank;

[0043] 30. Precision control device; 31. Flowmeter;

[0044] 40. Raw material gas source;

[0045] 50. CVD reaction device. Specific embodiments

[0046] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above description of the drawings are intended to cover non-exclusive inclusion.

[0048] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present invention, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0049] Referring to "embodiments" herein means that specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appears at various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0050] In the description of the embodiments of the present invention, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0051] In the description of the embodiments of the present invention, the term "a plurality" means two or more (including two). Similarly, "a plurality of groups" means two or more groups (including two groups), and "a plurality of pieces" means two or more pieces (including two pieces).

[0052] CVD ZnSe is a II-VI group semiconductor material with a direct transition type energy band structure, having excellent optical transmission performance (wide transmission band @ 0.5 - 18 μm, high optical uniformity, refractive index uniformity in the ppm order, and extremely low light absorption coefficient). It is an important military and civilian infrared optical material and can be used as optical components such as lenses, prisms, and windows of high-resolution infrared thermal imagers.

[0053] The CVD ZnSe material is prepared by chemical vapor deposition (CVD), using zinc (Zn) and hydrogen selenide (H 2 Se) as the initial raw materials and argon (Ar) as the carrier. The reaction equation is:

[0054] H 2 Se (g) + Zn (g) = ZnSe (s) + H 2 (g)

[0055] During the material preparation process, the purity of the raw material gas will directly affect the optical properties of the material. Impurities in the gas will cause inclusions and defects inside the material, affect the mass uniformity of the material, and cause scattering and absorption of the material. Especially when used in high-resolution imaging systems and high-power lasers, it will cause a significant reduction in the service life and working quality of the device.

[0056] The present invention provides a raw material gas pretreatment system and method for preparing CVD ZnSe, ensuring that hydrogen selenide (H 2 Se) gas is effectively filtered and purified before entering the CVD reaction device, further stabilizing the gas pressure, efficiently maintaining the dynamic balance of the deposition process, and improving the product purity.

[0057] The first aspect of the present invention provides a raw material gas pretreatment system 100 for preparing CVD ZnSe as shown in Figure 4 . As introduced in combination with Figures 5 to 10 , the raw material gas pretreatment system 100 includes a gas grading absorption and filtration device 10, a circulation buffer device 20, and a precision control device 30 that are connected in sequence. The gas grading absorption and filtration device 10 is used to connect to the raw material gas source 40, and the precision control device 30 is used to connect to the CVD reaction device 50 to ensure effective filtration and purification of the raw material gas before entering the CVD reaction device 50, stabilizing the gas pressure through the circulation buffer device 20, and maintaining the dynamic balance of the deposition process through the precision control device 30. Among them, the raw material gas includes H 2 Se gas.

[0058] In an embodiment of the present invention, the gas graded absorption filter device 10 includes a multi-stage filter device and an adsorption device 13 which are connected to each other; wherein the multi-stage filter device is connected to the raw gas source 40, and the adsorption device 13 is connected to the circulation buffer device 20; the multi-stage filter device is mainly a physical filtration method, which is used to filter trace solid particles in the gas. Through multi-stage filtration, trace solid particles including Se in the gas can be fully filtered. The adsorption device 13 mainly uses physical adsorption or chemical reaction to adsorb small molecular gas impurities to avoid the reduction of material purity due to gas impurities entering the reactor.

[0059] In the embodiments of the present invention, the multi-stage filtering device can be designed with filtering stages according to actual needs, such as two-stage filtering, three-stage filtering, etc. In some embodiments of the present invention, the multi-stage filtering device includes a primary filter 11 and a secondary filter 12 arranged in series, wherein the primary filter 11 is connected to the raw gas source 40, and the secondary filter 12 is connected to the adsorption device 13. Through the secondary filtration, trace solid particles including Se element in the gas can be fully filtered.

[0060] In some embodiments of the present invention, the filter particle size of the primary filter 11 is ≥0.1 μm, and the filter particle size of the secondary filter 12 is ≥20 nm. The primary filter 11 needs to satisfy the particle size ≥0.1 μm, that is, the minimum particle size that can be filtered is 0.1 μm; the secondary filter 12 needs to satisfy the particle size ≥20 nm, that is, the minimum particle size that can be filtered is 20 nm.

[0061] In some embodiments of the present invention, the filter particle size of the primary filter 11 is ≥1 μm, and the filter particle size of the secondary filter 12 is ≥50 nm. The primary filter 11 needs to satisfy the particle size ≥1 μm, that is, the minimum particle size that can be filtered is 1 μm; the secondary filter 12 needs to satisfy the particle size ≥50 nm, that is, the minimum particle size that can be filtered is 50 nm.

[0062] In some embodiments of the present invention, the primary filter 11 includes one of a stainless steel composite mesh filter element and a quartz filter element.

[0063] In some embodiments of the present invention, the secondary filter 12 includes one of carbon nanotubes and nanofilters. Figure 5 A schematic diagram of the structure of carbon nanotubes in an embodiment of the present invention is shown.

[0064] In the embodiment of the present invention, due to the high viscosity of Se, the multi-stage filter device is set up in a one-in-one-standby mode, and a pressure transmission device is set on the delivery pipeline to monitor the pressure. When the pressure value exceeds the set deviation, an alarm is issued to remind the user to switch to the standby multi-stage filter device in time to avoid filter blockage due to high viscosity.

[0065] In an embodiment of the present invention, the adsorption device 13 includes a molecular sieve 130. Refer to Figure 6 As shown, the molecular sieve 130 adsorbs small molecule gas impurities through physical or chemical reactions, avoiding the decrease in material purity caused by the entry of gas impurities into the reaction furnace.

[0066] In some embodiments of the present invention, the molecular sieve 130 can be one or a combination of models such as 5A, 13X, AW-500, etc.

[0067] In an embodiment of the present invention, after the above filtration and adsorption, the impurities in the gas have been removed. However, due to environmental and front-end device factors, the pressure may be unstable, and a circulation buffer device 20 is needed to stabilize the pressure.

[0068] In an embodiment of the present invention, the circulation buffer device 20 includes a first-stage buffer tank 21 and a second-stage buffer tank 22 arranged in series, as well as a bypass and a pressure monitor arranged between the first-stage buffer tank 21 and the second-stage buffer tank 22; the pressure difference between the first-stage buffer tank 21 and the second-stage buffer tank 22 is monitored by the pressure monitor, and the pressure is stabilized through circulation buffering via the bypass. A bypass circulation buffering parameter reflux ratio is set. Specifically, the reflux ratio is the ratio of the flow rate at the outlet of the second-stage buffer tank to the flow rate returning to the inlet of the first-stage buffer tank through the bypass. In an embodiment of the present invention, the reflux ratio is set to 1:4 to 1:7. Exemplarily, the reflux ratio can be one of 1:4, 1:5, 1:6, 1:7 or any value satisfying the above range.

[0069] In some embodiments of the present invention, a number of quartz balls are filled in the first-stage buffer tank 21. Refer to Figure 7 As shown, filling the first-stage buffer tank 21 with quartz balls can effectively disperse the air flow and reduce the pressure.

[0070] In some embodiments of the present invention, the diameter of the quartz balls is 3 mm to 8 mm. Exemplarily, the diameter of the quartz balls can be one of 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm or any value satisfying the above range.

[0071] In some embodiments of the present invention, a number of buffer plates are provided in the first-stage buffer tank 21. By arranging a plate structure in the first-stage buffer tank 21, the air flow passes through the gaps of the plate structure for buffering.

[0072] Refer to Figure 8As shown, several buffer plates are independently and vertically arranged inside the primary buffer tank 21, and are spaced along the length direction of the primary buffer tank 21. The gas inlet and gas outlet of the primary buffer tank 21 are respectively opened on the opposite sides of the primary buffer tank 21 along the length direction. A first gas channel that is communicated is formed between two adjacent buffer plates, and the first gas channel communicates the gas inlet and gas outlet of the primary buffer tank 21.

[0073] In an embodiment of the present invention, the gap or spacing between two adjacent buffer plates is 5 mm to 10 mm. Exemplarily, the gap between two adjacent buffer plates can be one of 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or any value satisfying the above range value.

[0074] In an embodiment of the present invention, a plurality of laminar flow plates are arranged inside the secondary buffer tank 22. By arranging a laminar flow plate laminated structure inside the secondary buffer tank 22, the air flow passes through the gaps between the laminar flow plates for buffering.

[0075] See Figure 9 As shown, several laminar flow plates are independently and horizontally arranged inside the secondary buffer tank 22, and are laminated along the height direction of the secondary buffer tank 22. The gas inlet and gas outlet of the secondary buffer tank 22 are respectively opened on the opposite sides of the secondary buffer tank 22 along the length direction. A second gas channel that communicates with the primary buffer tank 21 is formed between two adjacent laminar flow plates, and the second gas channel communicates the gas inlet and gas outlet of the secondary buffer tank 22.

[0076] In some embodiments of the present invention, the gap between two adjacent laminar flow plates, which can also be understood as the spacing between two adjacent laminar flow plates along the height direction, is 0.3 mm to 1 mm. Exemplarily, the gap between two adjacent laminar flow plates can be one of 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm or any value satisfying the above range value.

[0077] In an embodiment of the present invention, the precision control device 30 includes a flow meter 31 and a pressure transmitter that are communicatively connected. The pressure transmitter monitors the pressure change in real time and feeds back a signal to the flow meter 31 for micro-dynamic adjustment of the gas flow.

[0078] The second aspect of the present invention provides a method for preprocessing a source gas for preparing CVD ZnSe, and the source gas preprocessing method is based on the source gas preprocessing system described in the first aspect.

[0079] See Figure 3As shown, the key to the raw gas pretreatment method for preparing CVD ZnSe in the present invention is that the raw gas passes through the gas graded absorption filter device, the circulation buffer device and the precision control device in sequence to ensure that the raw gas is effectively filtered and purified before entering the CVD reaction device.

[0080] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the amounts of the experimental reagents, unless otherwise specified, are the amounts of reagents used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0081] Example 1

[0082] A raw material gas pretreatment system and method for preparing CVD ZnSe, see Figure 3 and Figure 4 As shown, the raw gas pretreatment system 100 for preparing CVDZnSe includes a gas grading absorption filter device 10, a circulation buffer device 20 and a precision control device 30 which are connected in sequence; the gas grading absorption filter device 10 is externally connected to a raw gas source 40, and the precision control device 30 is connected to a CVD reaction device 50.

[0083] The gas graded absorption filter device 10 adopts a two-stage filter device and a molecular sieve 130. The first-stage filter 11 adopts a stainless steel composite mesh filter element for filtration, and the filtration particle size is 0.1μm. The second-stage filter 12 adopts carbon nanotube filtration, and the filtration particle size is 20nm. Through the two-stage filtration, trace solid particles including Se element in the gas can be fully filtered. Because Se has a large viscosity, the two-stage filter device adopts one for use and one for backup. A pressure transmission is set on the pipeline. When the pressure value exceeds the deviation, an alarm is issued and the backup route is switched in time to avoid filter blockage due to high viscosity. The molecular sieve 130 adopts 5A molecular sieve.

[0084] After filtration and adsorption, impurities in the gas have been removed, but due to environmental and front-end device factors, the pressure is unstable, and a circulating buffer device 20 is needed to stabilize the pressure. The circulating buffer device 20 includes a primary buffer tank 21 and a secondary buffer tank 22 arranged in series. The primary buffer tank 21 is filled with quartz balls with a diameter of 5 mm, which can effectively disperse the airflow and reduce the pressure; the secondary buffer tank 22 uses a number of laminar sheets, and the gap between two adjacent laminar sheets is 1 mm. A bypass and a pressure gauge are set between the primary buffer tank 21 and the secondary buffer tank 22. When the pressure difference between the primary buffer tank 21 and the secondary buffer tank 22 is large, the bypass is opened for circulating buffering to stabilize the pressure, and the reflux ratio is set to 1:5.

[0085] After the pressure is stabilized, the gas will enter the precision control device 30, in which the gas flow pressure transmitter is provided at the rear end of the flow meter 31. When the pressure changes, the signal is fed back to the flow meter 31 for micro-dynamic adjustment to ensure that the flow is not disturbed by the pressure, and finally the raw gas H of CVD ZnSe is realized. 2 Se pretreatment.

[0086] Example 2

[0087] A raw material gas pretreatment system and method for preparing CVD ZnSe, see Figure 3 and Figure 4 As shown, the raw gas pretreatment system 100 for preparing CVDZnSe includes a gas grading absorption filter device 10, a circulation buffer device 20 and a precision control device 30 which are connected in sequence; the gas grading absorption filter device 10 is externally connected to a raw gas source 40, and the precision control device 30 is connected to a CVD reaction device 50.

[0088] The gas graded absorption filter device 10 adopts a double-stage filter device and a molecular sieve 130. The first-stage filter 11 adopts a quartz filter element for filtration, and the filtration particle size is 1 μm. The second-stage filter 12 adopts a nano filter mesh, and the filtration particle size is 50 nm. Through double-stage filtration, trace solid particles including Se in the gas can be fully filtered. Because Se has a high viscosity, the double-stage filter device adopts one for use and one for backup to avoid clogging of the filter due to high viscosity. The molecular sieve 130 adopts 5A and 13X molecular sieves to form multi-stage adsorption.

[0089] After filtration and adsorption, impurities in the gas have been removed, but the pressure is unstable, and a circulating buffer device 20 is needed to stabilize the pressure. The circulating buffer device 20 includes a primary buffer tank 21 and a secondary buffer tank 22 arranged in series. A plurality of buffer plates are arranged in the primary buffer tank 21, and the airflow passes through the gap of the plate structure for buffering; a plurality of laminar sheets are used in the secondary buffer tank 22, and the gap between two adjacent laminar sheets is 1mm. A bypass and a pressure gauge are arranged between the primary buffer tank 21 and the secondary buffer tank 22. When the pressure difference between the primary buffer tank 21 and the secondary buffer tank 22 is large, the bypass is opened for circulating buffering to stabilize the pressure, and the reflux ratio is 1:5.

[0090] After the pressure is stabilized, the gas will enter the precision control device 30, in which the gas flow pressure transmitter is provided at the rear end of the flow meter 31. When the pressure changes, the signal is fed back to the flow meter for micro-dynamic adjustment to ensure that the flow is not disturbed by the pressure, and finally the raw gas H of CVD ZnSe is realized. 2 Se pretreatment.

[0091] Performance Testing

[0092] In the present invention, the raw material gas H of CVD ZnSe is pretreated by using the method in Example 1 or Example 2, and the CVD ZnSe material is prepared from this raw material gas H. At the same time, the CVD ZnSe material prepared in the prior art is used as a comparative example. 2 Se is pretreated, and the CVD ZnSe material is prepared from this raw material gas H 2 Se. Meanwhile, the CVD ZnSe material prepared in the prior art is used as a comparative example.

[0093] The CVD ZnSe material prepared in the present invention and the CVD ZnSe material in the prior art are tested for performance by the same method.

[0094] Sample side test piece: It can reflect the mass uniformity of zinc selenide every day during the entire production cycle.

[0095] Specifically, the two sides of zinc selenide perpendicular to the growth direction are sliced, polished, and polished to obtain a side view. Among them, Figure 1 shows the side view of the CVD ZnSe material in the prior art, with relatively serious delamination and poor mass uniformity of the material. Figure 2 shows the side view of the CVD ZnSe material in the present invention, where the side delamination disappears and the mass uniformity is greatly improved.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A raw gas pretreatment system for preparing CVD ZnSe, characterized in that: It comprises a gas graded absorption filter device, a circulation buffer device and a precision control device which are connected in sequence; the gas graded absorption filter device is used to connect to an external raw gas source, the precision control device is used to connect to a CVD reaction device to ensure that the raw gas is effectively filtered and purified before entering the CVD reaction device, and the gas pressure is stabilized by the circulation buffer device, and the dynamic balance of the deposition process is maintained by the precision control device; Wherein, the raw material gas includes H2Se gas.

2. The raw material gas pretreatment system for preparing CVD ZnSe according to claim 1, characterized in that: The gas graded absorption and filtering device comprises a multi-stage filtering device and an adsorption device which are connected to each other; the multi-stage filtering device is connected to the raw gas source, and the adsorption device is connected to the circulation buffer device; The multi-stage filtering device is used to filter trace solid particles in the gas, and the adsorption device is used to adsorb small molecular gas impurities.

3. The raw material gas pretreatment system for preparing CVD ZnSe according to claim 2, characterized in that: The multi-stage filtering device comprises a primary filter and a secondary filter arranged in series, the primary filter is connected to the raw gas source, and the secondary filter is connected to the adsorption device; Preferably, the filter particle size of the primary filter is ≥0.1 μm, and the filter particle size of the secondary filter is ≥20 nm; Preferably, the filtration particle size of the primary filter is ≥1 μm, and the filtration particle size of the secondary filter is ≥50 nm.

4. The raw material gas pretreatment system for preparing CVD ZnSe according to claim 3, characterized in that: The primary filter comprises a stainless steel composite mesh filter element or a quartz filter element; and / or, The secondary filter comprises one of carbon nanotubes and nano filter nets.

5. The raw material gas pretreatment system for preparing CVD ZnSe according to claim 2, characterized in that: The adsorption device includes a molecular sieve; Preferably, the multi-stage filtering device adopts a one-backup-one-use configuration, and is provided with a pressure transmission device for pressure monitoring.

6. The raw material gas pretreatment system for preparing CVD ZnSe according to claim 1, characterized in that: The circulating buffer device comprises a primary buffer tank and a secondary buffer tank arranged in series, and a bypass and a pressure monitor arranged between the primary buffer tank and the secondary buffer tank; The pressure monitor is used to monitor the pressure difference between the primary buffer tank and the secondary buffer tank and the bypass is used for circulating buffering to stabilize the pressure, and the reflux ratio is 1:4 to 1:

7.

7. The raw material gas pretreatment system for preparing CVD ZnSe according to claim 6, characterized in that: A plurality of quartz balls or a plurality of buffer plates are arranged in the primary buffer tank; and / or, A plurality of laminar flow sheets are arranged in the secondary buffer tank; Preferably, the diameter of the quartz ball is 3 mm to 8 mm; Preferably, the gap between two adjacent laminar sheets is 0.3 mm to 1 mm.

8. The raw material gas pretreatment system for preparing CVD ZnSe according to claim 7, characterized in that: A plurality of buffer plates are independently erected inside the primary buffer tank and are arranged at intervals along the length direction of the primary buffer tank, and a first gas channel connected to each other is formed between two adjacent buffer plates; Preferably, a plurality of the laminar sheets are independently and horizontally arranged inside the secondary buffer tank, and are stacked along the height direction of the secondary buffer tank, and a second gas channel connected to the primary buffer tank is formed between two adjacent laminar sheets.

9. The raw material gas pretreatment system for preparing CVD ZnSe according to claim 1, characterized in that: The precision control device includes a flow meter and a pressure transmitter that are communicatively connected. The pressure transmitter monitors pressure changes in real time and feeds back signals to the flow meter to perform micro-dynamic adjustments to the gas flow.

10. A method for pretreating raw material gas for preparing CVD ZnSe, characterized in that: The raw gas pretreatment method is based on the raw gas pretreatment system according to any one of claims 1 to 9; The raw gas pretreatment method comprises: The raw gas passes through the gas graded absorption filtration device, the circulation buffer device and the precision control device in sequence to ensure that the raw gas is effectively filtered and purified before entering the CVD reaction device.

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