Molecular beam epitaxial shutter and device

Abstract

The invention relates to a molecular beam epitaxial shutter and device, and relates to the technical field of epitaxial growth. According to the molecular beam epitaxial shutter, the included angle is formed between the first blade and the second blade of the shutter piece, so that when the shutter piece shields the furnace opening of the source furnace, molecular beam current and heat radiation emitted from the furnace opening of the source furnace are obliquely intersected with the shutter piece, and the molecular beam current and the heat radiation fall outside the source furnace after being reflected by the shutter piece; therefore, the problem that an existing shutter structure cannot effectively prevent the source material from splashing and heat from being reflected to the furnace opening of the source furnace, so that the epitaxial growth stability and the coating quality of equipment are affected is solved.

Description

Technical Field

[0001] This invention relates to the field of epitaxial growth technology, and in particular to a molecular beam epitaxy shutter and device. Background Technology

[0002] Molecular beam epitaxy (MBE) is a method for preparing single-crystal thin films by epitaxial growth of atoms or molecules that constitute the crystal and are doped onto the surface of a substrate under ultra-high vacuum conditions, with a certain thermal motion speed and a certain composition ratio.

[0003] During thin film growth, a corresponding "shutter baffle" (hereinafter referred to as "shutter") is set at the source furnace opening. When the shutter is closed, it blocks the beam, while when it is open, it allows the beam to pass through. Through the control of the shutter, molecular beam epitaxy technology can precisely control the composition ratio of each single-crystal thin film.

[0004] like Figure 1 As shown, in conventional MBE, when shutter 101 is closed, it is perpendicular to the direction of the main molecular beam 1021. When the MBE growth chamber space is small, shutter 101 is close to the source furnace 103. When the molecular beam epitaxy shutter is closed, the main molecular beam 1021 is reflected by the shutter to form the reflected main beam 1023, and the secondary molecular beam 1022 is reflected by the shutter to form the reflected secondary beam 1024. This leads to the following problems: 1. The shutter 101 is too close to the furnace opening 104. Source materials such as gallium and indium are reflected by the shutter 101 to the furnace opening 104, causing severe corrosion of the tantalum sheath and heat insulation sheet of the gallium furnace. After indium accumulates at the furnace opening, it causes the furnace body to stick to the water cooling jacket, and the evaporation of impurities leads to doping and surface defects. 2. Since the temperature of shutter 101 is much lower than that of crucible 105, the cold material formed after the source material is reflected by shutter 101 is sputtered onto crucible 105, which can easily cause defects on the epitaxial surface. 3. The shutter 101 will also reflect thermal radiation back to the crucible 105. The moment the shutter opens and closes, it causes a sudden change in the temperature at the mouth of the crucible, which affects the stability of the growth rate.

[0005] Existing shutter structures cannot effectively prevent source material splashing and heat reflection, affecting the stability of epitaxial growth and coating quality. There is an urgent need to design new shutters to solve these problems. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a molecular beam epitaxy shutter and device.

[0007] A molecular beam epitaxy shutter for blocking or avoiding the molecular beam stream emitted from the furnace opening of a source furnace includes: A shutter blade, comprising a first leaf, a second leaf at a first included angle with the first leaf, and a first axis connecting the first leaf and the second leaf; A shutter rod, one end of which is connected with the shutter blade, for driving the shutter blade to swing so that the shutter blade blocks or avoids the molecular beam flux; The size of the first included angle satisfies the following relationship: Wherein, θ is a half angle of the first included angle, D is the source furnace diameter, H is the height from the plane where the furnace mouth is located to the first axis, r is the radius of the shutter blade projection to the plane where the furnace mouth is located, which can completely block the molecular beam flux, h is the thickness of the shutter blade.

[0008] Preferably, the shutter blade surface is provided with a reinforcing rib, which is obliquely intersected with the first axis.

[0009] Preferably, the first leaf and the second leaf are double-layer hollow structures with equal intervals.

[0010] Preferably, the shutter rod comprises: A first shutter rod, which is arranged in the hollow structure of the second leaf near one side of the first axis; A second shutter rod, which is integrally formed with the first shutter rod, and an angle is formed between the second shutter rod and the first shutter rod, and the size of the angle between the second shutter rod and the first shutter rod is determined according to the condition that the shutter blade can completely block the molecular beam flux from being sprayed to the substrate; Wherein, the first shutter rod is a flat structure, the thickness of the first shutter rod is equal to the interval of the hollow structure, and the angle between the surface of the first shutter rod and the central axis of the second shutter rod is the same as the half angle of the first included angle.

[0011] Preferably, the shutter blade further comprises a shutter blade support structure, which is a flat structure fixed in the hollow structure of the first leaf, the shutter blade support structure and the first shutter rod are mirror distributed about the first axis, and the thickness of the shutter blade support structure is equal to the interval of the hollow structure.

[0012] Preferably, the molecular beam epitaxy shutter further comprises a counterweight, which is a flat structure fixed in the hollow structure of the second leaf and located away from the first axis, the thickness of the counterweight is equal to the interval of the hollow structure, and the length of the counterweight is less than the length of the shutter blade support structure.

[0013] Preferably, the shutter blade further includes a shutter blade support structure, which is a gasket disposed within the hollow structure of the first blade, and the thickness of the gasket is equal to the space between the hollow structures.

[0014] Preferably, the shutter plate further includes a shutter plate support structure, which consists of multiple sets of protrusions evenly distributed on the shutter plate, the multiple sets of protrusions facing the hollow structure, and each set of protrusions being fixedly connected within the hollow structure by welding.

[0015] Preferably, the shutter lever includes: Main rod; The first rod includes a first rod body disposed within the hollow structure of the first blade and a first leg connected to the main rod. The angle formed by the surface of the first rod body and the central axis of the first leg is the same as half of the first included angle. The second rod includes a second rod body disposed within the hollow structure of the second blade and a second leg connected to the main rod. The angle formed by the surface of the second rod body and the central axis of the second leg is the same as half of the first included angle. The first and second legs are fixedly connected to the main rod; the first and second rod bodies are flat structures, the thickness of the first and second rod bodies is equal to the space between the hollow structures, the first and second rod bodies are mirror images of each other about the first axis within the hollow structure, and the angles formed by the first and second rod bodies with the first axis are the same acute angles.

[0016] A molecular beam epitaxy apparatus includes: a source furnace; and a molecular beam epitaxy shutter as described above.

[0017] Compared with the prior art, the above-described technical solution of the present invention has the following advantages: In the molecular beam epitaxy shutter of the present invention, the first and second blades of the shutter plate have an included angle, so that the molecular beam stream and thermal radiation emitted from the furnace mouth of the source furnace intersect the shutter plate at an angle. After being reflected by the shutter plate, the molecular beam stream and thermal radiation fall outside the source furnace, thereby avoiding the problem that the existing shutter structure cannot effectively block the splashing of source material and thermal reflection to the furnace mouth, which affects the stability of epitaxial growth and the coating quality of the equipment. Attached Figure Description

[0018] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the closed state of the molecular beam epitaxy shutter in existing technology.

[0020] Figure 2 This is a front view of the molecular beam epitaxy shutter in Embodiment 1 of the present invention.

[0021] Figure 3 This is a top view of the molecular beam epitaxy shutter in Embodiment 1 of the present invention.

[0022] Figure 4 This is a side view of the molecular beam epitaxy shutter in Embodiment 1 of the present invention.

[0023] Figure 5 This is a front view of the molecular beam epitaxy shutter in the closed state of the present invention.

[0024] Figure 6 This is a side view of the molecular beam epitaxy shutter in the closed state of the present invention.

[0025] Figure 7 This is a front view of the molecular beam epitaxy shutter in the open state of the present invention.

[0026] Figure 8 This is a side view of the molecular beam epitaxy shutter in the open state of the present invention.

[0027] Figure 9 This is a schematic diagram of the first included angle of the present invention.

[0028] Figure 10 This is a front view of the shutter lever in Embodiments 2 to 4 of the present invention.

[0029] Figure 11 This is a side view of the shutter lever in Embodiments 2 to 4 of the present invention.

[0030] Figure 12 This is a front view of the molecular beam epitaxy shutter in Embodiment 2 of the present invention.

[0031] Figure 13 This is a top view of the molecular beam epitaxy shutter in Embodiment 2 of the present invention.

[0032] Figure 14 This is a front view of the molecular beam epitaxy shutter in Embodiment 3 of the present invention.

[0033] Figure 15 This is a top view of the molecular beam epitaxy shutter in Embodiment 3 of the present invention.

[0034] Figure 16 This is a front view of the molecular beam epitaxy shutter in Embodiment 4 of the present invention.

[0035] Figure 17 This is a top view of the molecular beam epitaxy shutter in Embodiment 4 of the present invention.

[0036] Figure 18 This is a front view of the molecular beam epitaxy shutter in Embodiment 5 of the present invention.

[0037] Figure 19 This is a top view of the molecular beam epitaxy shutter in Embodiment 5 of the present invention.

[0038] Figure 20 This is a side view of the molecular beam epitaxy shutter in Embodiment 5 of the present invention.

[0039] Explanation of reference numerals in the accompanying drawings: 101, shutter; 1021, main molecular beam; 1022, secondary molecular beam; 1023, reflected main beam; 1024, reflected secondary beam; 103, source furnace; 104, furnace opening; 105, crucible; 2011, first blade; 2012, second blade; 2013, hollow structure; 202, shutter lever; 2021, first shutter lever; 2022, second shutter lever; 301, first axis; 401, central axis of the second shutter lever; 501, shutter plate support structure; 502, counterweight; 601, rivet; 701, main rod; 7021, first rod body; 7022, first leg; 7031, second rod body; 7032, second leg. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0041] Example 1:

[0042] like Figures 2-8 As shown, this application provides a molecular beam epitaxy shutter for blocking or avoiding the molecular beam emitted from the furnace opening 104 of the source furnace 103, comprising: A shutter blade, the shutter blade including a first blade 2011, a second blade 2012 forming a first angle with the first blade 2011, and a first axis 301 connecting the first blade 2011 and the second blade 2012; A shutter lever 202, one end of which is connected to the shutter plate, is used to drive the shutter plate to swing so that the shutter plate blocks or avoids the molecular beam.

[0043] When the shutter plate blocks the furnace opening 104, the molecular beam epitaxy shutter is in a closed state, such as... Figures 5-6 As shown; when the shutter plate avoids the furnace opening 104, the molecular beam epitaxy shutter is in the open state, as... Figures 7-8 As shown.

[0044] In this embodiment, as Figure 9As shown, the molecular beam is divided into a main molecular beam 1021 and a secondary molecular beam 1022. In actual production, the thermal radiation range is approximately the same as the molecular beam range. When the molecular beam epitaxial shutter is closed, the main molecular beam 1021 is reflected by the shutter to form a reflected main beam 1023, and the secondary molecular beam 1022 is reflected by the shutter to form a reflected secondary beam 1024. To ensure that the molecular beam and thermal radiation emitted from the furnace opening 104 fall outside the source furnace 103 after being reflected by the shutter, and considering the shutter thickness, the first included angle satisfies the following relationship: tan(2 α )>( D / 2) / H , θ >arctan( r / h ), in, α =90°- θ , α The incident angle of the molecular beam main current is 1021. θ It is half of the first included angle. D The diameter of the source furnace 103, H The height of the plane containing furnace opening 104 from the first axis 301. r The radius of the shutter that can precisely block the molecular beam stream from being projected onto the plane where the furnace opening 104 is located. h The thickness of the shutter plate; From the above formula, the size of the first included angle satisfies the following relationship: .

[0045] In this embodiment, when the shutter block blocks the furnace opening 104 of the source furnace 103, the molecular beam and thermal radiation emitted from the furnace opening 104 intersect the shutter block at an angle, so that the molecular beam and thermal radiation fall outside the source furnace 103 after being reflected by the shutter block.

[0046] Optionally, since the temperature at the furnace opening 104 of the source furnace 103 is usually as high as 800-900°C, in order to enhance the strength and stability of the shutter plate, the surface of the shutter plate is provided with reinforcing ribs, which intersect the first axis 301 at an inclination.

[0047] Optionally, to avoid deformation of the shutter blade during frequent swinging, the first blade 2011 and the second blade 2012 are double-layered hollow structures 2013 with equal intervals.

[0048] Example 2:

[0049] like Figures 10-13As shown, in this embodiment, in addition to the features included in Embodiment 1, the following features are also included.

[0050] In this embodiment, the shutter lever 202 includes: The first shutter lever 2021 is disposed in the hollow structure 2013 of the second blade 2012 on the side close to the first axis 301. The second shutter lever 2022 is integrally formed with the first shutter lever 2021, and the second shutter lever 2022 and the first shutter lever 2021 form a certain angle. The size of the angle between the second shutter lever 2022 and the first shutter lever 2021 is such that the shutter plate can completely block the molecular beam stream from being sprayed onto the substrate. The first shutter lever 2021 is a flat structure, the thickness of the first shutter lever 2021 is equal to the space between the hollow structure 2013, and the angle formed by the surface of the first shutter lever 2021 and the central axis 401 of the second shutter lever is the same as half of the first included angle.

[0051] In this embodiment, the material of the flat structure is selected to meet the requirements of the ultra-high vacuum chamber and MBE epitaxial growth conditions, such as tantalum, molybdenum, boron nitride, etc.

[0052] In this embodiment, the first shutter lever 2021 and the second blade 2012 are connected by rivets 601.

[0053] In this embodiment, the shutter blade further includes a shutter blade support structure 501. The shutter blade support structure 501 is a flat structure fixed to the hollow structure of the first blade 2011 by rivets 601. The shutter blade support structure 501 and the first shutter lever 2021 are mirror images of each other about the first axis 301, and the thickness of the shutter blade support structure 501 is equal to the spatial spacing of the hollow structure 2013.

[0054] Since the shutter blade is usually a thin tantalum sheet, its hollow structure 2013 is prone to collapse when lacking support. In this embodiment, by setting a shutter blade support structure 501, the support force between the first blade 2011 and the second blade 2012 can be effectively improved, preventing the shutter blade from collapsing.

[0055] In this embodiment, the molecular beam epitaxy shutter further includes a counterweight 502. The counterweight 502 is a flat structure fixed inside the hollow structure of the second blade 2012 and located on the side away from the first axis 301. The thickness of the counterweight 502 is equal to the spatial spacing of the hollow structure 2013, and the length of the counterweight 502 is less than the length of the shutter support structure 501.

[0056] Since the shutter lever 202 is located on the side close to the second blade 2012, after the shutter support structure 501 is set in the first blade 2011, the center of gravity of the shutter plate does not coincide with the central axis of the shutter lever 202, which may cause problems such as shutter plate obstruction when opening and closing. In this embodiment, by setting a counterweight 502 on the side of the second blade 2012 away from the first axis 301, the center of gravity of the shutter plate can be effectively balanced, making it coincide with the central axis of the shutter lever 202, thereby avoiding damage during frequent swinging.

[0057] Example 3:

[0058] like Figures 14-15 As shown, the difference between this embodiment and embodiment two is that there is no counterweight, and the shutter support structure 501 is a pad disposed in the hollow structure 2013 of the first blade 2011. The thickness of the pad is equal to the space between the hollow structure 2013 and the first blade 2011 is connected by rivets 601.

[0059] In this embodiment, the material of the gasket is selected to meet the requirements of the ultra-high vacuum chamber and MBE epitaxial growth conditions, such as tantalum, molybdenum, boron nitride, etc. In this embodiment, using a gasket as the shutter support structure 501 helps to reduce the overall mass of the shutter, making its opening and closing movement smoother.

[0060] Example 4:

[0061] like Figures 16-17 As shown, the difference between this embodiment and embodiment two is that: there is no counterweight; the first shutter lever 2021 and the second blade 2012 are connected by spot welding; and the shutter support structure 501 consists of multiple sets of protrusions evenly distributed on the shutter blade, the multiple sets of protrusions facing the hollow structure 2013, and each set of protrusions is fixedly connected in the hollow structure 2013 by spot welding.

[0062] In this embodiment, by utilizing multiple sets of welded protrusions, the use of gaskets or flat structures is avoided. On the one hand, this reduces the overall mass of the shutter plate, thereby making its opening and closing movement smoother. On the other hand, the multiple sets of welded protrusions are evenly distributed on the shutter plate, which helps to improve the support strength of the shutter plate.

[0063] Example 5:

[0064] like Figures 18-20 As shown, in this embodiment, in addition to the features included in Embodiment 1, the following features are also included.

[0065] In this embodiment, the shutter lever 202 includes: Main rod 701; The first rod includes a first rod body 7021 disposed in the hollow structure 2013 of the first blade 2011 and a first support leg 7022 connected to the first rod 701. The angle formed by the surface of the first rod body 7021 and the central axis of the first support leg 7022 is the same as half of the first included angle. The second rod includes a second rod body 7031 disposed in the hollow structure 2013 of the second blade 2012 and a second leg 7032 connected to the main rod 701. The angle formed by the surface of the second rod body 7031 and the central axis of the second leg 7032 is the same as half of the first included angle. The first support leg 7022 and the second support leg 7032 are fixedly connected to the main rod 701 by rivets 601. The first rod body 7021 and the second rod body 7031 are flat structures. The thickness of the first rod body 7021 and the second rod body 7031 is equal to the space between the hollow structure 2013. The first rod body 7021 and the second rod body 7031 are mirror images of each other about the first axis 301 within the hollow structure 2013, and the angles formed by the first rod body 7021 and the second rod body 7031 with the first axis 301 are the same acute angles.

[0066] In this embodiment, the first and second rods are mirror-distributed so that the center of gravity of the molecular beam epitaxy shutter coincides with the center line. This makes the molecular beam epitaxy shutter less prone to unilateral wear and jamming during opening and closing, resulting in smoother operation and greatly extending the service life of the molecular beam epitaxy shutter.

[0067] Example 6:

[0068] This application provides a molecular beam epitaxy apparatus, comprising: Source furnace 103; and molecular beam epitaxy shutter as described in any of the above embodiments.

[0069] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A molecular beam epitaxy shutter for blocking or avoiding a molecular beam flux emitted from a source furnace mouth, characterized in that, The shutter piece comprises a first leaf, a second leaf at a first included angle with the first leaf, and a first axis connecting the first leaf and the second leaf. The shutter piece is connected to one end of a shutter rod for driving the shutter piece to swing so that the shutter piece blocks or avoids the molecular beam flux. The shutter piece surface is provided with a reinforcing rib which is obliquely intersected with the first axis. The first included angle satisfies the following relationship: wherein, The first leaf and the second leaf are double-layer hollow structures with equal intervals. is a half angle of the first included angle, D is the source furnace diameter, H is a height from a plane where the furnace mouth is located to the first axis, r is a radius of a shutter piece projection to the plane where the furnace mouth is located, which just can completely shield the molecular beam flux, h is the shutter piece thickness.

2. The molecular beam epitaxy shutter of claim 1, wherein, The shutter rod comprises:

3. The molecular beam epitaxy shutter of claim 1, wherein, A first shutter rod which is arranged in the hollow structure of the second leaf near one side of the first axis; 4. The molecular beam epitaxy shutter of claim 3, wherein, A second shutter rod which is integrally formed with the first shutter rod and forms an angle with the first shutter rod, and the angle between the second shutter rod and the first shutter rod is determined according to the size of the angle so that the shutter piece can completely block the molecular beam flux from spraying onto the substrate; The first shutter rod is a flat structure, the thickness of the first shutter rod is equal to the interval of the hollow structure, and the angle between the surface of the first shutter rod and the central axis of the second shutter rod is equal to half of the first included angle. The shutter piece further comprises a shutter piece support structure which is a flat structure fixed in the hollow structure of the first leaf, the shutter piece support structure is mirror-distributed about the first axis with the first shutter rod, and the thickness of the shutter piece support structure is equal to the interval of the hollow structure. The molecular beam epitaxy shutter further comprises a counterweight which is a flat structure fixed in the hollow structure of the second leaf and located away from the first axis, the thickness of the counterweight is equal to the interval of the hollow structure, and the length of the counterweight is less than the length of the shutter piece support structure.

5. The molecular beam epitaxy shutter of claim 4, wherein, The shutter piece further comprises a shutter piece support structure which is a gasket arranged in the hollow structure of the first leaf, and the thickness of the gasket is equal to the interval of the hollow structure.

6. The molecular beam epitaxy shutter of claim 5, wherein, The shutter piece further comprises a shutter piece support structure which is a plurality of groups of protrusions uniformly distributed on the shutter piece, the plurality of groups of protrusions are directed towards the hollow structure, and each group of protrusions is fixedly connected in the hollow structure by welding.

7. The molecular beam epitaxy shutter of claim 4, wherein, The shutter rod comprises:

8. The molecular beam epitaxy shutter of claim 4, wherein, A main rod; 9. The molecular beam epitaxy shutter of claim 3, wherein, A first secondary rod which comprises a first secondary rod body arranged in the hollow structure of the first leaf and a first leg connected with the main rod, and the angle between the surface of the first secondary rod body and the central axis of the first leg is equal to half of the first included angle; A second secondary rod which comprises a second secondary rod body arranged in the hollow structure of the second leaf and a second leg connected with the main rod, and the angle between the surface of the second secondary rod body and the central axis of the second leg is equal to half of the first included angle; ​ ​ The first supporting leg and the second supporting leg are fixedly connected with the main rod; the first secondary rod body and the second secondary rod body are flat structures, the thicknesses of the first secondary rod body and the second secondary rod body are equal to the spacing of the hollow structure, the first secondary rod body and the second secondary rod body are mirror-distributed about the first axis in the hollow structure, and the first secondary rod body and the second secondary rod body form the same acute angle with the first axis.

10. A molecular beam epitaxy apparatus, characterized by comprising: Comprising: a source furnace; and A molecular beam epitaxy shutter according to any one of claims 1-9.

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