A low-damage sputtering coating equipment for manufacturing high-performance solar cells

Abstract

The present invention discloses a low-damage sputtering coating apparatus for manufacturing high-performance solar cells, which comprises a vacuum chamber, a cathode target, an anode and a sample stage disposed in the vacuum chamber; the anode is located between the cathode target and the sample stage; during operation, plasma is generated between the anode and the cathode, and the target atoms / molecules bombarded by gas ions pass through the opening formed in the anode region and are deposited on the sample substrate on the surface of the sample stage. By adjusting the relative positions of the cathode target, the anode and the sample in the sputtering coating apparatus, the present invention restricts the generation of plasma between the anode and the cathode without affecting the sample area, thereby effectively avoiding damage to the surface of the cell and the surface of the deposited material during the sputtering coating process, and further improving the performance of the solar cell.

Description

Technical Field

[0001] The present invention relates to a low-damage sputtering coating device for manufacturing high-performance solar cells. Background Art

[0002] Magnetron sputtering devices are an important tool for thin film deposition and are widely used in fields such as optical thin films, electronic devices, and photovoltaic cells. By sputtering different materials, specific structures can be formed on the surface of a sample or its chemical properties can be changed, and it can also be used for surface modification, coating protective layers, etc.

[0003] The earliest magnetron sputtering devices mainly consisted of a cathode, an anode, and a vacuum chamber, and electrons were accelerated by an electric field to generate the sputtering process. Such devices were simple but had low control precision. With the increasing requirements for controlling the sputtering process, a magnetic field was further introduced to control the movement trajectory of electrons, improving the sputtering uniformity and efficiency. This technological improvement enabled magnetron sputtering to be widely used in microelectronics, optics, and other fields. With the increasing requirements for the complexity of material components and structure control, multi-target sputtering technology was developed, which could simultaneously sputter multiple materials in the same vacuum chamber to achieve the preparation of composite thin films. To obtain a higher deposition rate and improve the thin film quality, high-energy sputtering technology was also developed by increasing the electron energy and the temperature of the sputtered material. Further, to introduce specific chemical elements or compounds into the thin film, reactive sputtering technology was developed, which could introduce reactive gases during the sputtering process to form compound thin films.

[0004] Since the concept of magnetron sputtering was proposed in the late 19th century and early 20th century and put into practical application in 1976, magnetron sputtering devices have experienced a development process from simple structures to complex control, from single materials to composite materials, and from uniform deposition to reactive sputtering. Over the years, the structure of magnetron sputtering devices has used the target material (target) as the cathode, with the metal substrate as the anode placed opposite the cathode target, and the sample placed directly above the anode or between the cathode and the anode, that is, in the region between the electron beam and the sputtered material.

[0005] For inert materials and highly stable materials, the traditional design can meet the requirements. However, with the upgrading of material science, especially the preparation requirements of solar cells, the traditional design of magnetron sputtering devices is no longer applicable to the preparation of materials with easily damaged surface interfaces such as perovskite solar cells, amorphous silicon solar cells, and crystalline silicon heterojunction solar cells. When the above-mentioned easily damaged materials are bombarded by high-energy electrons and ions between the cathode and the anode, the overall performance of the battery will rapidly decline. Summary of the Invention

[0006] Object of the Invention: The object of the present invention is to provide a sputtering coating device, which can effectively avoid damaging the deposited materials on the battery wafer during the preparation of high-performance solar cell wafers when using this sputtering coating device.

[0007] Technical Solution: The sputtering coating device described in the present invention includes a vacuum chamber, a cathode target, an anode, and a sample stage disposed in the vacuum chamber; the cathode target, the anode, and the sample stage are coaxially arranged; the anode is located between the cathode target and the sample stage; during operation, plasma is generated between the anode and the cathode, and the target atoms / molecules bombarded by gas ions pass through the opening formed in the anode region and are deposited on the sample on the surface of the sample stage.

[0008] Among them, within the voltage range of 500 - 1000V, the vertical distance between the sample stage and the anode is not greater than 5 cm; the distance between the sample stage and the anode will be adaptively adjusted with the change of voltage.

[0009] Among them, the cathode target can be designed in different shapes according to the sample size, such as circular or rectangular; the cathode target can use a magnetron target or a non-magnetron target. The material of the anode is not limited to metal and can be a conductive oxide or a conductive polymer material.

[0010] Among them, a movable baffle is provided between the anode and the cathode target for covering the opening of the anode region at the initial stage of coating.

[0011] Among them, the anode is annular; the area of the annular opening is not less than the area of the upper surface of the sample stage; the anode is fixed in the vacuum chamber through a connecting bracket.

[0012] Among them, the movable baffle rotates through a rotating assembly or moves laterally through a pull rod assembly.

[0013] Among them, the anode includes multiple conductive plates, and the anode formed by the multiple conductive plates is a centrosymmetric structure, and the area of the opening of the anode region formed by the multiple conductive plates is not less than the area of the upper surface of the sample stage.

[0014] Among them, the multiple conductive plates are respectively driven to move through the corresponding rotating assembly or pull rod assembly, so that an opening of the anode region is formed between the multiple conductive plates or the opening of the anode region is closed.

[0015] Among them, when the sample stage is a metal sample stage, the sample stage is connected to an external power supply to ground the sample stage or input a negative voltage. By inputting a voltage of -50 - 0V to the sample stage, further prevent electrons from bombarding the sample surface;

[0016] Among them, a circular magnetic confinement coil is added around the sample stage. A circular magnetic confinement coil can also be added around the sample stage. When a current is introduced into the coil, an external magnetic field is formed above the sample stage to further control the plasma region.

[0017] Among them, the sample stage is a rotatable sample stage. The sample stage can be fixed in the vacuum chamber through a support; or it can rotate relative to the vacuum chamber, and the rotating sample stage can enhance the uniformity of film coating.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: By adjusting the relative positions of the cathode target, anode, and sample in the sputtering coating equipment, the present invention restricts the generation of plasma between the cathode and anode and does not affect the sample area, thereby effectively avoiding damage to the deposited materials on the battery chip during the sputtering coating process, and further improving the performance of the solar cell. Description of the Drawings

[0019] Figure 1 It is a structural design diagram of a low-damage sputtering coating equipment with a fixed anode for Example 1;

[0020] Figure 2 It is a top view of the annular anode in Example 1;

[0021] Figure 3 It is a schematic connection diagram of the connecting rod and the vacuum chamber in Example 1;

[0022] Figure 4 It is Schematic Connection Diagram I of the connecting rod and the baffle;

[0023] Figure 5 It is Schematic Connection Diagram II of the connecting rod and the baffle;

[0024] Figure 6 It is a structural design diagram of a low-damage sputtering coating equipment with a movable anode (closed state) for Example 2;

[0025] Figure 7 It is a top view of the movable anode in the closed state in Example 2;

[0026] Figure 8 It is a structural design diagram of a low-damage sputtering coating equipment with a movable anode (open state) for Example 2;

[0027] Figure 9 It is a top view of the movable anode in the open state in Example 2;

[0028] Figure 10 It is a schematic connection diagram of the pull rod and the vacuum chamber;

[0029] Figure 11 It is a structural design diagram of a low-damage sputtering coating equipment with a movable anode (closed state) for Example 3;

[0030] Figure 12 It is a structural design diagram of a low-damage sputtering coating equipment with a movable anode (open state) for Example 3;

[0031] Figure 13 The microscopic structure diagram of the surface of amorphous silicon oxide prepared by using a traditional sputtering device;

[0032] Figure 14 The microscopic structure diagram of the surface of amorphous silicon oxide prepared by using the device of Embodiment 2 of the present invention;

[0033] Figure 15 The comparison of the photoelectric conversion efficiency of crystalline silicon solar cells prepared by using a traditional sputtering device and the device of Embodiment 2 of the present invention;

[0034] Figure 16 The comparison of the photoelectric conversion efficiency of perovskite solar cells prepared by using a traditional sputtering device and the device of Embodiment 2 of the present invention. Detailed implementation manners

[0035] Embodiment 1

[0036] As Figures 1 - 2 shown, the low-damage sputtering coating device of the present invention includes a stainless-steel vacuum chamber 1, a cathode target 2, an anode 10, and a sample stage 6 disposed in the vacuum chamber 1. The cathode target 2, the anode 10, and the sample stage 6 are coaxially arranged. In the stainless-steel vacuum chamber 1, the cathode target 2 is a circular magnetron target, and the cathode target 2 is connected with a cathode power line 3, a circulating cooling water inlet pipe 4, and a circulating cooling water outlet pipe 5. The cathode target 2 is connected to an external power supply through the cathode power line 3, and the cathode target 2 is communicated with an external water storage tank through the circulating cooling water inlet pipe 4 and the circulating cooling water outlet pipe 5. The bottom of the sample stage 6 is fixedly connected with a rotating shaft 81. The rotating shaft 81 is fixedly connected with the bottom plate of the vacuum chamber 1 through a bearing seal, and the rotating shaft 81 passes through the vacuum chamber 1 and is fixedly connected with the driving end of a motor 8. A heating resistance wire and a temperature controller 9 are arranged inside the sample stage 6. The sample stage 6 is placed directly below the cathode target 2.

[0037] Within the voltage range of 500 - 1000V, the distance between the sample stage 6 and the anode 10 is not greater than 5 cm.

[0038] In this embodiment, a circular copper plate is used as the anode 10, and the anode 10 is connected to an external power supply through an anode power line 11. A movable baffle 13 is provided above the annular anode 10.

[0039] As Figure 4As shown, the baffle 13 is a circular baffle. The rotating assembly includes a connecting rod 14 connected to the baffle. One end of the connecting rod 14 is fixedly connected to the baffle 13, and the other end of the connecting rod 14 extends out of the vacuum chamber 1 and is fixedly connected to the top cover of the vacuum chamber 1 through a sealing ring and a fastening nut. The further downward movement of the baffle 13 is restricted by a limiting cross bar. When it is necessary to rotate the baffle 13, pull out the limiting cross bar, loosen the fastening nut, and rotate the connecting rod 14 to drive the baffle to rotate. When it is necessary to expose the annular opening 101, drive the baffle 13 to rotate 180° towards the side wall of the vacuum chamber 1; when it is necessary to cover the annular opening 101, rotate the connecting rod 14 in the reverse direction to drive the baffle 13 to move 180° away from the side wall of the vacuum chamber 1. Among them, the baffle is circular, with a diameter larger than the diameter of the cathode target, and the diameter of the baffle 13 is also larger than the diameter of the annular opening 101; the area of the annular opening 101 is not less than the area of the upper surface of the sample stage 6.

[0040] As Figure 3 shown, on the inner side wall of the top cover of the vacuum chamber 1, a limiting hole with the same diameter as the connecting rod 14 is opened, and on the outer side wall of the top cover of the vacuum chamber 1, a groove is opened for fixedly connecting with the fastening nut through internal and external threads. The groove has internal threads, the inner ring of the fastening nut is a smooth surface sleeved on the connecting rod 14, the outer ring of the fastening nut has external threads, and an O-ring and a washer are also embedded in the groove. The connecting rod 14 is fixedly connected to the top cover of the vacuum chamber 1 through the fastening nut.

[0041] When the device works, a plasma region is generated between the cathode target 2 and the anode 10. After the target material 12 is bombarded by ions, the surface contaminants and the target material are deposited on the surface of the baffle 13. After 0 to 60 seconds, rotate the connecting rod 14 to move the baffle 13 above the anode 10 away, and the target material passes through the annular opening 101 and is deposited on the sample on the surface of the sample stage 6. A viewing window made of transparent organic glass is provided at the position of the stainless steel vacuum chamber 1 corresponding to the baffle 13, and it is judged whether the baffle 13 is moved away through the viewing window.

[0042] As Figure 5 shown, in this embodiment, the baffle 13 can also be two rectangular baffles joined together. The two baffles are respectively driven to rotate by corresponding connecting rods. When it is necessary to open the two joined baffles to form an opening, the two baffles can be rotated 180° in opposite directions respectively, and the area of the opening formed by the two baffles is larger than the area of the annular opening 101.

[0043] Embodiment 2

[0044] As Figures 6 - 9As shown in the figure, the low-damage sputtering coating equipment of the present invention includes a stainless-steel vacuum chamber 1, a cathode target 2, an anode 10, and a sample stage 6 disposed in the vacuum chamber 1. The cathode target 2, the anode 10, and the sample stage 6 are coaxially arranged. In the vacuum chamber 1, the cathode target 2 is a circular magnetron target, and the cathode target 2 is connected with a cathode power line 3, a circulating cooling water inlet pipe 4, and a circulating cooling water outlet pipe 5. The cathode target 2 is connected to an external power source through the cathode power line 3, and the cathode target 2 is communicated with an external water storage tank through the circulating cooling water inlet pipe 4 and the circulating cooling water outlet pipe 5. The sample stage 6 is fixed in the vacuum chamber 1 through a support 7. A heating resistance wire and a temperature controller 9 are arranged inside the sample stage 6. The sample stage 6 is placed directly below the cathode target 2.

[0045] In the voltage range of 500 - 1000V, the distance between the sample stage 6 and the anode 10 is not greater than 5 cm.

[0046] In this embodiment, two rectangular copper plates are used as the anode 10 and also as the baffle at the initial stage of coating. The anode 10 is connected to an external power source through an anode power line 11.

[0047] When the device works, a plasma region is generated between the cathode target 2 and the anode 10. After the target material 12 is bombarded by ions, the surface contaminants and the target material are deposited on the surface of the anode 10. After 0 - 60 seconds, the two rectangular copper plates that are horizontally joined together are moved to the open (separated) state through a pull rod assembly. The target material passes through the opening 102 formed in the anode region and is deposited on the sample on the surface of the sample stage 6. A viewing window made of transparent organic glass is provided at the corresponding position of the stainless-steel vacuum chamber 1 for the anode 10, and it is judged whether the anode 10 is moved away through the viewing window. Or in this embodiment, a transparent organic glass vacuum chamber is directly adopted.

[0048] The pull rod assembly includes a pull rod 8 connected to the rectangular copper plate. Each rectangular copper plate is connected to three pull rods 8 (two of the pull rods 8 are connected to the upper surface of the copper plate, and one pull rod 8 is connected to the lower surface of the copper plate). One end of the pull rod 8 is fixedly connected to the rectangular copper plate, and the other end of the pull rod 8 extends out of the vacuum chamber 1 and is fixedly connected to the side wall of the vacuum chamber 1 through a sealing ring and a fastening nut. Loosen the fastening nut (the loosening degree is such that the pull rod can be pulled), pull the pull rod 8, and drive the two rectangular copper plates to move relatively, that is, move towards the side wall of the vacuum chamber at the same time; or push the pull rod 8 to drive the two rectangular copper plates to move towards each other, that is, move away from the side wall of the vacuum chamber at the same time.

[0049] As Figure 10As shown in the figure, a limiting hole with a diameter 4 mm larger than that of the pull rod 8 is opened on the inner side wall of the vacuum chamber 1. An insulating ceramic sleeve with a wall thickness of 2 mm is sleeved between the limiting hole and the pull rod 8. A groove for fixedly connecting with a fastening nut through internal and external threads is opened on the outer side wall of the vacuum chamber. The groove has internal threads, and the inner ring of the fastening nut is a smooth surface. An insulating ceramic sleeve with a wall thickness of 2 mm is also sleeved between the inner ring of the nut and the pull rod 8; the outer ring has external threads, so that the fastening nut fixes the pull rod on the side wall of the vacuum chamber. An O-ring seal and a washer are also embedded in the groove. The pull rod 8 is fixedly connected to the side wall of the vacuum chamber 1 through the fastening nut; when the fastening nut is loosened, the pull rod 8 is manually moved horizontally relative to the vacuum chamber 1, and the surface of the pull rod 8 is coated with an insulating rubber coating.

[0050] Example 3

[0051] As Figures 11 - 12 shown, the low-damage sputtering coating equipment of the present invention includes a stainless-steel vacuum chamber 1 and a cathode target 2, an anode 10 and a sample stage 6 arranged in the vacuum chamber 1. The cathode target 2, the anode 10 and the sample stage 6 are coaxially arranged; in the stainless-steel vacuum chamber 1, the cathode target 2 is a circular magnetron target, and a cathode power line 3, a circulating cooling water inlet pipe 4 and a circulating cooling water outlet pipe 5 are connected to the cathode target 2; the cathode target 2 is connected to an external power supply through the cathode power line 3, and the cathode target 2 is communicated with an external water storage tank through the circulating cooling water inlet pipe 4 and the circulating cooling water outlet pipe 5. The sample stage 6 is fixed in the vacuum chamber 1 through a support 7; in this embodiment, a metal sample stage 6 is used, and the sample stage 6 is connected to an external power supply through a power line 16, and a voltage of -50 to 0 V is input to the sample stage 6. A heating resistance wire and a temperature controller 9 are arranged inside the sample stage 6; the sample stage 6 is placed directly below the cathode target 2.

[0052] In the voltage range of 500 to 1000 V, the distance between the sample stage 6 and the anode 10 is not greater than 5 cm.

[0053] In this embodiment, two rectangular copper plates are used as the anode 10 and also as a baffle at the initial stage of coating. The anode 10 is connected to an external power supply through an anode power line 11. In this embodiment, a magnetic confinement device is also provided outside the sample stage 6. The magnetic confinement device includes a cylindrical bracket 15 and an electromagnetic coil 14 wound around the cylindrical bracket 15. Electric current is passed through the electromagnetic coil 14 in the magnetic confinement device, so as to input a magnetic field 13 above the sample stage 6 to further control the plasma region.

[0054] The pull rod assembly in Example 3 is the same as that in Example 2, and the only difference is that there is a protrusion on the pull rod 8 as a limiting component. When the device works, a plasma region is generated between the cathode target 2 and the anode 10. After the target material 12 is bombarded by ions, the surface contaminants and the target material are deposited on the surface of the anode 10. After 0 to 60 seconds, the pull rod 101 is pulled to move the two rectangular copper plates joined together horizontally to the open (separated) state, and the target material passes through the opening 102 formed in the anode region and is deposited on the sample on the surface of the sample stage 6. There is no observation window provided on the vacuum chamber 1 in this embodiment. Therefore, there is a protrusion on the pull rod 8 as a limiting component. When pulling the pull rod 8, it can be stopped from pulling out further when reaching the position of the protrusion.

[0055] Sputtering the amorphous silicon oxide material for the passivation layer of crystalline silicon solar cells using a traditional magnetron sputtering device: Install the silicon oxide target; place the monocrystalline silicon sample substrate on the sample stage; turn on the power supply; turn on the circulating water; check the gas valve to ensure it is closed, and turn on the vacuum pump to evacuate to a pressure value of 10 -4 Pa; maintain the evacuation, turn on the argon gas valve to keep the pressure in the vacuum chamber at about 3×10 -1 Pa; turn on the DC power supply, adjust the power to 100W, turn on the RF power supply switch, and glow discharge starts in the cavity, and the film coating begins; the film coating time is 10 min; after the film coating is completed, turn off the DC power supply, close the gas valve, open the vacuum valve to break the vacuum, and after the temperature drops to <100 °C, turn off the main power supply; Figure 12 For the surface of the amorphous silicon oxide prepared using the traditional sputtering device as described above, through Figure 12 it can be seen that the surface of the obtained sample material is rough and has many defects.

[0056] Sputtering the amorphous silicon oxide material for the passivation layer of crystalline silicon solar cells using the device in Example 2: Install the silicon oxide target; place the monocrystalline silicon sample substrate on the sample stage 6; turn on the power supply; turn on the circulating water; check the gas valve to ensure it is closed, and turn on the vacuum pump to evacuate to a pressure value of 10 -4 Pa; maintain the evacuation, turn on the argon gas valve to keep the pressure in the vacuum chamber at about 3*10 -1 Pa; ensure that the two rectangular copper plates are closed, turn on the DC power supply, adjust the power to 100W, turn on the RF power supply switch, and glow discharge starts in the cavity; wait for 1 min. After the contaminants on the target surface are removed, pull the pull rod 8 simultaneously to both sides to move the two rectangular copper plates to the open (separated) state, and the target material passes through the opening 102 formed in the anode region and is deposited on the sample on the surface of the sample stage 6, and the film coating begins; the film coating time is 10 min; after the film coating is completed, turn off the DC power supply, close the gas valve, open the vacuum valve to break the vacuum, push the pull rod 8 simultaneously to both sides to close the two rectangular copper plates, and after the temperature drops to <100 °C, turn off the main power supply. Figure 13For the surface of amorphous silicon oxide prepared by the device of the above-mentioned Usage Example 2, through Figure 13 it can be seen that the surface of the material is smooth, dense and has few defects.

[0057] Prepare crystalline silicon solar cells with the samples of Figure 13 and Figure 14 respectively, and the photoelectric conversion efficiency of the crystalline silicon solar cells is as shown in Figure 15 ; the photoelectric conversion efficiency of the perovskite solar cells prepared by using the traditional sputtering equipment and the equipment of Example 2 of the present invention is as shown in Figure 16 , indicating that the photoelectric conversion efficiency of the solar cells prepared by using the equipment of the present invention is significantly improved.

Claims

1. A method for preparing a passivation layer of an amorphous silicon oxide solar cell, characterized in that: The method is prepared by using the following equipment. The equipment includes a vacuum chamber (1), a cathode target (2), an anode (10), and a sample stage (6) disposed in the vacuum chamber (1); the anode (10) is located between the cathode target (2) and the sample stage (6); during operation, plasma is generated between the anode (10) and the cathode, and the target atoms / molecules bombarded by gas ions are deposited onto the sample on the surface of the sample stage (6) through the opening formed in the anode region. Among them, in the voltage range of 500 - 1000V, the distance between the sample stage (6) and the anode (10) is not greater than 5 cm; the anode (10) is composed of two rectangular copper plates, and the anode (10) formed by the two rectangular copper plates is a centrosymmetric structure, and the opening area of the anode region formed by the two rectangular copper plates is not less than the area of the upper surface of the sample stage (6); the two rectangular copper plates are respectively driven to move by corresponding pull rod assemblies to form an opening in the anode region or to close the opening in the anode region. The specific process of the preparation method is as follows: Install a silicon oxide target; Place a single crystal silicon sample substrate on the sample stage (6); Turn on the power supply; Turn on the circulating water; Check the gas valve to ensure that the gas valve is closed, and turn on the vacuum pump to evacuate to a pressure value of 10 -4 Pa; Keep evacuating, turn on the argon gas valve to maintain the pressure in the vacuum chamber at 3×10 -1 Pa, ensure that the two rectangular copper plates are closed, turn on the DC power supply, adjust the power to 100 W, turn on the RF power supply switch, and glow discharge starts in the cavity; Wait for 1 min. After the contaminants on the target surface are removed, pull the pull rods (8) simultaneously to both sides to move the two rectangular copper plates to the open state. The target material passes through the opening (102) formed in the anode region and deposits on the sample on the surface of the sample stage (6), and the film coating starts; The film coating time is 10 min.

2. The preparation method according to claim 1, wherein: When the sample stage (6) is a metal sample stage, the sample stage (6) is connected to an external power supply to ground the sample stage (6) or input a negative voltage.

3. The preparation method according to claim 2, characterized in that: A circular magnetic confinement coil (14) is added around the sample stage (6).

4. The preparation method according to claim 1, characterized in that: The sample stage (6) is a rotatable sample stage.

Images