Heating window used in ultrahigh vacuum environment

Abstract

The invention relates to an accessory applied to molecular beam epitaxy equipment, in particular to a heating window used in an ultrahigh vacuum environment, the front side and the rear side of an observation window shell are in sealed connection with a cavity connecting pipe and observation equipment respectively, and a window opening through hole is formed in the observation window shell; the coating heating element, the shielding heat insulation sheet and the heating window insulation fixing assembly are all located in the window opening through hole; a conductive film is plated on the film-plated substrate; shielding heat insulation sheets are arranged on the front side and the rear side of the film-plated heating element; a plurality of heating window insulation fixing assemblies are arranged on the peripheries of the coating heating element and the shielding heat-resisting sheet in the circumferential direction and are used for supporting and fixing the coating substrate and the shielding heat-resisting sheet; one end of a vacuum heating electrode lead is hermetically connected with the observation window shell, the other end is connected with a power supply, and the end of the lead is clamped at a contact point of the conductive film. Elemental substances in an equipment environment cannot be deposited on the surface of the quartz glass window, and the problem that substances in a cavity of molecular beam epitaxy equipment are deposited on the surface of the window after long-time operation is solved.

Description

Technical Field

[0001] The invention relates to accessories used in molecular beam epitaxy equipment, in particular to a heating window used in an ultra-high vacuum environment. Background Art

[0002] During long-term operation, the observation window of the growth chamber of the molecular beam epitaxy equipment will continuously deposit elemental substances sputtered from the substrate stage in the cavity, causing the light transmittance of the observation window surface to gradually decrease. Finally, a layer of opaque material film will be formed on the surface of the observation window, thereby affecting the accuracy of the substrate stage temperature measurement through the observation window by external equipment, seriously affecting the quality of the molecular beam epitaxial coating products. Summary of the invention

[0003] In view of the above-mentioned problems existing in the observation window of the growth chamber of the existing molecular beam epitaxy equipment during long-term operation, the purpose of the present invention is to provide a heating window for use in an ultra-high vacuum environment.

[0004] The objective of the present invention is achieved through the following technical solutions: The present invention comprises a film-coated heating element, a shielding insulation sheet, an observation window shell, a heating window insulating fixing component and a vacuum heating electrode lead, wherein the front and rear sides of the observation window shell are respectively sealed and connected to the cavity pipe and the observation device, the observation window shell is provided with a window opening through hole, the film-coated heating element, the shielding insulation sheet and the heating window insulating fixing component are all located in the window opening through hole; the film-coated heating element comprises a film-coated substrate, the film-coated substrate is coated with a conductive film, the front and rear sides of the film-coated heating element are both provided with a shielding insulation sheet for shielding the conductive film; a plurality of heating window insulating fixing components are circumferentially arranged around the periphery of the film-coated heating element and the shielding insulation sheet, the outer edges of the film-coated substrate and the shielding insulation sheet are both supported and fixed by the heating window insulating fixing components; one end of the vacuum heating electrode lead is sealed and connected to the observation window shell, the other end of the vacuum heating electrode lead is connected to a power source, the lead end of the vacuum heating electrode lead penetrates into the observation window shell and is clamped at the contact point of the conductive film.

[0005] Wherein: the heating window insulation fixing component includes a spring and a fixing piece, and the inner wall of the window opening through hole is circumferentially provided with grooves of the same number and one-to-one corresponding to the heating window insulation fixing components, and the fixing piece is accommodated in the groove, one end of the spring abuts against the bottom of the groove, and the other end of the spring is inserted into the fixing piece and abuts against the inside of the fixing piece, and the inward side of the fixing piece is respectively clamped with the outer edges of the coating base and the shielding insulation sheet.

[0006] A through hole penetrating the fixing part is provided in the middle of the fixing part, and a window clamping groove and a shielding film clamping groove are respectively provided on the inner surface of the fixing part, the window clamping groove passes through the through hole radially, and shielding film clamping grooves are provided on both sides of the window clamping groove; the outer edge of the coated substrate is clamped in the window clamping groove, and the outer edges of the shielding heat insulation films on the front and rear sides are respectively clamped in the shielding film clamping grooves on both sides.

[0007] The coating substrate is a high temperature resistant transparent material, and the coating substrate has the same shape as the window opening through hole, which is circular, square, diamond or elliptical.

[0008] The coated substrate protrudes axially along the window opening through hole toward the middle of one side of the cavity, and the periphery of the protruding part is plated with a conductive film, and the conductive film is a ring with a notch, and the contact point is provided at the notch; the lead end of the vacuum heating electrode lead is grooved, and the contact point of the conductive film is clamped in the groove.

[0009] The shielding insulation sheet is annular, the outer edge size of the conductive film is smaller than the outer edge size of the coated substrate, and the inner edge size of the conductive film is smaller than the inner edge size of the shielding insulation sheet; a distance is left between the outer edge of the conductive film and the heating window insulation fixing assembly.

[0010] The material of the shielding heat insulation sheet is high temperature resistant metal, the shielding heat insulation sheet is not in contact with the observation window shell, and the thickness of the shielding heat insulation sheet is less than 1 / 2 of the thickness of the observation window shell.

[0011] Both axial end surfaces of the observation window shell where the window opening through hole is provided are processed with CF knife edges for vacuum metal sealing, and a plurality of screw through holes are evenly provided on the observation window shell along the circumferential direction.

[0012] The advantages and positive effects of the present invention are: The present invention maintains a high temperature on the surface of the quartz glass window by continuously heating with electricity, so that elemental substances in the equipment environment cannot be deposited on the surface of the quartz glass window, thereby ensuring the accuracy of temperature measurement by a temperature measuring device of a heated window carton substrate stage of the present invention, and solving the problem of material deposition on the window surface in the cavity of the molecular beam epitaxy equipment after long-term operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural front view of the present invention; Figure 2 for Figure 1 Right side sectional view; Figure 3 It is a front cross-sectional view of the present invention; Figure 4 This is a front view of the structure of the quartz glass window of the present invention; Figure 5 for Figure 4A side cross-sectional view of Figure 6 It is a schematic diagram of the finished structure of the coated heating element of the present invention; Figure 7 It is a schematic diagram of the structure of the fixing member of the present invention; Figure 8 It is a schematic diagram of the structure of the present invention connected to the cavity; Among them: 1 is a spring, 2 is a fixing part, 3 is a coated heating element, 4 is a shielding insulation sheet, 5 is a quartz glass window, 6 is an observation window shell, 7 is a metal sealing gasket, 8 is a vacuum heating electrode lead, 9 is a cavity pipe, 10 is an observation device, 11 is a cavity, 12 is a CF knife edge, 13 is a window opening through hole, 14 is a window clamping groove, 15 is a shielding sheet clamping groove, 16 is a through hole, 17 is a conductive film, and 18 is a through hole for screws. DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with the accompanying drawings.

[0015] like Figures 1 to 3 As shown, the present invention comprises a film-coated heating element 3, a shielding heat-insulating sheet 4, an observation window shell 6, a heating window insulating fixing assembly and a vacuum heating electrode lead 8, wherein the front and rear sides of the observation window shell 6 are respectively sealed and connected to the cavity pipe 9 and the observation device 10, and a window opening through hole 13 is provided on the observation window shell 6, and the film-coated heating element 3, the shielding heat-insulating sheet 4 and the heating window insulating fixing assembly are all located in the window opening through hole 13; the film-coated heating element 3 comprises a film-coated substrate, and a conductive film 17 is coated on the film-coated substrate, and the front and rear sides of the film-coated heating element 3 are both provided with a shielding heat-insulating sheet 4 The shielding insulation sheet 4 is used to shield the conductive film 17 that generates heat during operation; a plurality of heating window insulating fixing components are circumferentially arranged around the periphery of the coated heating element 3 and the shielding insulation sheet 4, and the outer edges of the coated substrate and the shielding insulation sheet 4 are supported and fixed by the heating window insulating fixing components; one end of the vacuum heating electrode lead 8 is connected to the observation window shell 6, and is sealed with the observation window shell 6 through a metal sealing gasket 7, and the other end of the vacuum heating electrode lead 8 is connected to a power source, and the lead end of the vacuum heating electrode lead 8 is inserted into the observation window shell 6 and clamped at the contact point of the conductive film 17.

[0016] The coating substrate is a high temperature resistant transparent material, and the coating substrate has the same shape as the window opening through hole 13, which is circular, square, diamond or elliptical. Figures 1 to 6As shown, the coating substrate of this embodiment is a circular quartz glass window 5 that is resistant to high temperature (>200°C), and correspondingly, the window opening through hole 13 is also a circular hole; the quartz glass window 5 protrudes along the axial direction of the window opening through hole 13 in the middle of one side facing the cavity 11, and the protruding part is also circular, and a conductive film 17 is plated on the periphery of the protruding part. The conductive film 17 is a circular ring with a notch, and a contact point is provided at the notch, and the contact point is a metal sheet structure. The coating substrate material can also be selected from other transparent materials (such as ceramics or zirconium oxide) that are resistant to high temperature (>200°C).

[0017] like Figures 1 to 7 As shown, the heating window insulation fixing assembly of this embodiment includes a spring 1 and a fixing part 2. The inner wall of the window opening through hole 13 is circumferentially provided with grooves having the same number and one-to-one correspondence as the heating window insulation fixing assembly. The fixing part 2 is accommodated in the grooves. One end of the spring 1 abuts against the bottom of the groove, and the other end of the spring 1 is inserted into the fixing part 2 and abuts against the inside of the fixing part 2. The inward side of the fixing part 2 is clamped with the outer edges of the coating base and the shielding insulation sheet 4 respectively. The fixing member 2 of this embodiment is a hollow cylindrical structure, with a circular through hole 16 penetrating the fixing member 2 in the middle, and the through hole 16 is a stepped hole. The other end of the spring 1 abuts against the step of the through hole 16. The fixing member 2 is also provided with a window clamping groove 14 and a shielding plate clamping groove 15 on the surface of the inner side (i.e., the side facing the quartz glass window 5). The window clamping groove 14 passes through the through hole 16 in the radial direction, and shielding plate clamping grooves 15 are provided on both sides of the window clamping groove 14; the outer edge of the quartz glass window 5 is clamped in the window clamping groove 14, and the outer edges of the shielding heat insulation plates 4 on the front and rear sides are clamped in the shielding plate clamping grooves 15 on both sides. The heating window insulation fixing components of this embodiment are three groups, which are evenly arranged along the circumferential direction. The spring 1 is a high temperature resistant spring, and the temperature can reach 1000-1300°C; the material used for the fixing member 2 is high temperature resistant, and can be metal or other materials (such as molybdenum or tantalum).

[0018] The conductive film 17 of the present embodiment is in the shape of a ring with a gap. The conductive film 17 is made of a conductive material such as indium tin oxide.

[0019] The shielding heat-insulating sheet 4 of this embodiment is in a circular shape and is made of a high-temperature resistant metal, such as molybdenum or tantalum. The outer edge size of the conductive film 17 (i.e., the outer diameter of the conductive film 17) is smaller than the outer edge size of the coating substrate (i.e., the outer diameter of the quartz glass window 5), and the inner edge size of the conductive film 17 (i.e., the inner diameter of the conductive film 17) is smaller than the inner edge size of the shielding heat-insulating sheet 4 (i.e., the inner diameter of the shielding heat-insulating sheet 4); the outer edge of the conductive film 17 does not contact the insulating fixing assembly of the heating window, that is, there is a gap. After all the installation is completed, the shielding heat-insulating sheet 4 does not contact the observation window shell 6, and the thickness of the shielding heat-insulating sheet 4 is less than 1 / 2 of the thickness of the observation window shell 6.

[0020] In this embodiment, the lead end of the vacuum heating electrode lead 8 is grooved. During installation, the groove on the lead end is clamped on the contact point position of the conductive film 17.

[0021] In this embodiment, both axial end faces of the observation window housing 6 where the window opening through hole 13 is provided are processed with CF (Conflat Flange) blades 12 for vacuum metal sealing. Metal sealing gaskets (material can be oxygen-free copper) are placed at the CF blades 12 of the two end faces, which are sealed and connected with the cavity pipe 9 and the observation device 10. A plurality of screw through holes 18 are evenly provided on the observation window housing 6 along the circumferential direction, which are used to connect with the cavity pipe 9 and the observation device 10.

[0022] The working principle of the present invention is: The heating window of the present invention can be used in ultra-high vacuum environment (P<1×10 -5 Pa), such as Figure 8 As shown, one side of the observation window shell 6 is connected to the flange of the cavity pipe 9 of the growth chamber of the molecular beam epitaxy equipment, and the other side is connected to the ultra-high vacuum knife-edge sealed glass observation window (observation equipment 10). Metal sealing gaskets are placed between the observation window shell 6 and the cavity pipe 9 and between the observation window shell 6 and the ultra-high vacuum knife-edge sealed glass observation window, respectively, and are fixed by screws passing through the screw holes 18. The internal space of the observation window shell 6 is vacuum and the external atmosphere is atmosphere. The other end of the vacuum heating electrode lead 8 exposed to the atmosphere is connected to a power source. After power is turned on, the surface temperature of the base glass of the quartz glass window 5 of the coated heating element 3 is maintained at 200°C, which can effectively inhibit the deposition of elemental substances on the surface of the quartz glass window 5 in the vacuum environment of the cavity 11, ensure the accuracy of temperature measurement through the temperature measuring equipment of the heating window carton substrate stage of the present invention, and solve the problem of material deposition on the window surface in the cavity of the molecular beam epitaxy equipment after long-term operation.

Claims

1. A heated window for use in an ultra-high vacuum environment, characterized in that: The invention comprises a film-coated heating element (3), a shielding heat-insulating sheet (4), an observation window shell (6), a heating window insulating fixing assembly and a vacuum heating electrode lead (8), wherein the front and rear sides of the observation window shell (6) are respectively sealedly connected to a cavity pipe (9) and an observation device (10), the observation window shell (6) is provided with a window opening through hole (13), the film-coated heating element (3), the shielding heat-insulating sheet (4) and the heating window insulating fixing assembly are all located in the window opening through hole (13); the film-coated heating element (3) comprises a film-coated substrate, the film-coated substrate is coated with a conductive film (17), the film-coated heating element ( 3) are provided with shielding heat-insulating sheets (4) for shielding the conductive film (17) on both the front and rear sides; a plurality of heating window insulating fixing components are provided around the periphery of the coated heating element (3) and the shielding heat-insulating sheet (4); the outer edges of the coated substrate and the shielding heat-insulating sheet (4) are supported and fixed by the heating window insulating fixing components; one end of the vacuum heating electrode lead (8) is sealedly connected to the observation window shell (6), the other end of the vacuum heating electrode lead (8) is connected to a power source, and the lead end of the vacuum heating electrode lead (8) is inserted into the observation window shell (6) and clamped at the contact point of the conductive film (17).

2. The heated window for use in an ultra-high vacuum environment according to claim 1, characterized in that: The heating window insulation fixing assembly comprises a spring (1) and a fixing member (2); the inner wall of the window opening through hole (13) is provided with grooves in the circumferential direction, the number of which is the same as that of the heating window insulation fixing assembly and which correspond one to one; the fixing member (2) is accommodated in the grooves; one end of the spring (1) abuts against the bottom of the groove; the other end of the spring (1) is inserted into the fixing member (2) and abuts against the inside of the fixing member (2); the inward side of the fixing member (2) is clamped against the outer edges of the coating base and the shielding heat insulation sheet (4) respectively.

3. The heating window for use in an ultra-high vacuum environment according to claim 2, characterized in that: A through hole (16) penetrating the fixing member (2) is provided in the middle of the fixing member (2), and a window clamping groove (14) and a shielding sheet clamping groove (15) are respectively provided on the inner surface of the fixing member (2), the window clamping groove (14) radially passes through the through hole (16), and shielding sheet clamping grooves (15) are provided on both sides of the window clamping groove (14); the outer edge of the coated substrate is clamped in the window clamping groove (14), and the outer edges of the shielding heat insulation sheet (4) on the front and rear sides are respectively clamped in the shielding sheet clamping grooves (15) on both sides.

4. The heated window for use in an ultra-high vacuum environment according to claim 1, characterized in that: The coating substrate is a high temperature resistant transparent material, and the coating substrate has the same shape as the window opening through hole (13), which is circular, square, diamond or elliptical.

5. The heated window for use in an ultra-high vacuum environment according to claim 1, characterized in that: The coated substrate protrudes in the middle of one side toward the cavity (11) along the axial direction of the window opening through hole (13), and the outer periphery of the protruding portion is plated with a conductive film (17), the conductive film (17) is annular with a notch, and the contact point is provided at the notch; the lead end of the vacuum heating electrode lead (8) is grooved, and the contact point of the conductive film (17) is clamped in the groove.

6. The heated window for use in an ultra-high vacuum environment according to claim 1, characterized in that: The shielding heat-insulating sheet (4) is annular, the outer edge size of the conductive film (17) is smaller than the outer edge size of the coating substrate, and the inner edge size of the conductive film (17) is smaller than the inner edge size of the shielding heat-insulating sheet (4); a distance is left between the outer edge of the conductive film (17) and the heating window insulation fixing assembly.

7. The heated window for use in an ultra-high vacuum environment according to claim 1, characterized in that: The material of the shielding heat-insulating sheet (4) is high-temperature resistant metal, the shielding heat-insulating sheet (4) does not contact the observation window shell (6), and the thickness of the shielding heat-insulating sheet (4) is less than 1 / 2 of the thickness of the observation window shell (6).

8. The heated window for use in an ultra-high vacuum environment according to claim 1, characterized in that: The axial end surfaces of the observation window housing (6) on which the window opening through hole (13) is provided are both machined with CF knife edges (12) for vacuum metal sealing, and a plurality of screw through holes (18) are evenly provided in the circumferential direction on the observation window housing (6).

Images