Linear continuous plating method for improving n-face field passivation effect of heterojunction cell

Abstract

The present application relates to SHJ battery microcrystalline coating technology field, specifically relates to a kind of linear continuous coating method for improving heterojunction battery N face field passivation effect, comprising the following steps: step S1, the temperature of PECVD cavity is preset to 200-260 ℃, N-type monocrystalline silicon wafer is sent into PECVD cavity;Step S2, the phase angle of a pair of independent power supply in HPT power supply and passivation power supply is set to 0-180 °;Step S3, start first HPT power supply;Step S4, start first passivation power supply, obtain N1 layer on the surface of N-type monocrystalline silicon wafer;Then N2 layer, N3 layer are obtained in turn repeatedly;Step S9, N layer passivated N-type monocrystalline silicon wafer is sent out PECVD cavity;The present application forms electromagnetic field using power supply with 0-180 ° phase angle, controls deposition area while also speeding up coating rate, and since deposition area is controlled by electromagnetic field, therefore the effect that N layer gradient doping is realized in single cavity is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of SHJ battery microcrystalline coating, in particular to a linear continuous coating method for improving the N-face field passivation effect of heterojunction battery. BACKGROUND

[0002] The traditional HJT battery structure first deposits a very thin intrinsic amorphous silicon film (i-a-Si:H) and an N-type amorphous silicon film (n-a-Si:H) on the front surface of an N-type monocrystalline silicon wafer (c-Si), then deposits a very thin intrinsic amorphous silicon film (i-a-Si:H) and a P-type amorphous silicon film (p-a-Si:H) on the back surface of the silicon wafer to form a back surface field, then deposits a transparent oxide conductive film (TCO) on both surfaces of the battery, and finally makes metal electrodes on the TCO.

[0003] The current N-face technical solution on the market is as follows: after the carrier plate enters the cavity, it is heated to about 200 degrees, H2 / SiH4 is introduced, a certain ratio of doping gas PH3 is introduced, a suitable power supply power is turned on for deposition, and the carrier plate is stationary during the coating process. Because N doping needs gradient doping, after depositing N1, the cavity gas is pumped out (to prevent gas from entering the next cavity), the cavity valve is opened, the carrier plate enters the next cavity to continue the same method to deposit N2, N3, etc. Because the N layer needs gradient doping, multiple cavities are needed for the process, which increases the cost of equipment and the coating time, and the same cavity on the market cannot realize the entire N layer gradient doping process.

[0004] Therefore, how to overcome the problem that the existing microcrystalline coating process cannot perform multi-layer gradient doping in a single cavity is a technical problem that needs to be solved in the field. SUMMARY

[0005] The present application provides a linear continuous coating method for improving the N-face field passivation effect of heterojunction battery, to solve the problem that the existing N layer passivation process needs multiple cavities to deposit statically.

[0006] In a first aspect, the embodiments of the present disclosure provide a linear continuous coating method for improving N-face field passivation effect of a heterojunction cell, comprising the following steps: step S1, presetting the temperature of a PECVD cavity to 200-260 DEG C, and feeding an N-type monocrystalline silicon wafer into the PECVD cavity; step S2, setting the phase angle of a pair of independent power sources in an HPT power source and a passivation power source to 0-180 DEG; step S3, starting a first HPT power source, feeding 1000-3000 sccm of H2, setting the power of an electromagnetic field to 100-500 W, and setting the end pressure of the PECVD cavity to 60-90 Pa; step S4, starting a first passivation power source, feeding 500-2000 sccm of H2, 100-300 sccm of SiH4 and 50-100 sccm of PH3, setting the power of the electromagnetic field to 500-2000 W, and obtaining an N1 layer on the surface of the N-type monocrystalline silicon wafer, and setting the end pressure of the PECVD cavity to 60-90 Pa; step S5, starting a second HPT power source, feeding 1000-3000 sccm of H2, setting the power of the electromagnetic field to 100-500 W, and setting the end pressure of the PECVD cavity to 60-90 Pa; step S6, starting a second passivation power source, feeding 500-2000 sccm of H2, 100-300 sccm of SiH4 and 100-300 sccm of PH3, setting the power of the electromagnetic field to 500-2000 W, and obtaining an N2 layer on the surface of the N-type monocrystalline silicon wafer, and setting the end pressure of the PECVD cavity to 60-90 Pa; step S7, starting a third HPT power source, feeding 1000-3000 sccm of H2, setting the power of the electromagnetic field to 100-500 W, and setting the end pressure of the PECVD cavity to 60-90 Pa; step S8, starting a third passivation power source, feeding 500-2000 sccm of H2, 100-300 sccm of SiH4 and 100-500 sccm of PH3, setting the power of the electromagnetic field to 500-2000 W, and obtaining an N3 layer on the surface of the N-type monocrystalline silicon wafer, and setting the end pressure of the PECVD cavity to 60-90 Pa; and step S9, feeding the N-type monocrystalline silicon wafer with the N-layer passivation out of the PECVD cavity.

[0007] In an optional embodiment, the method further comprises: step S10, performing a minority carrier lifetime test to screen out the N-type monocrystalline silicon wafer with the N-layer passivation and a minority carrier lifetime lower than 5000 us.

[0008] In an optional embodiment, the thickness of the N1 layer is 0.5-5 nm.

[0009] In an optional embodiment, the thickness of the N2 layer is 0.5-5 nm.

[0010] In an optional embodiment, the thickness of the N3 layer is 4-15 nm.

[0011] In a second aspect, the embodiments of the present disclosure provide a linear continuous coating device, which is applied to the coating of a heterojunction cell by a PECVD coating equipment using the linear continuous coating method as described above, and the linear continuous coating device comprises: a coating module arranged above the inside of a PECVD cavity, which is used to guide the electromagnetic field while PECVD deposition is carried out in a manner that the HPT power supply and the passivation power supply are arranged in sequence and are spaced apart, wherein a pair of independent power supplies with a phase angle of 0°-180° are arranged in the HPT power supply and the passivation power supply; and a transmission module arranged below the inside of the PECVD cavity, which is used to transmit a carrier plate loaded with N-type monocrystalline silicon wafers through the PECVD cavity by rollers.

[0012] In an optional embodiment, the number of the HPT power supply and the passivation power supply is not less than three.

[0013] In an optional embodiment, the power of the HPT power supply is 100-500 W, and the power of the passivation power supply is 500-2000 W.

[0014] In an optional embodiment, at least one process pump is arranged at the end of the coating module.

[0015] In a third aspect, the embodiments of the present disclosure provide a linear continuous coating system, which comprises the linear continuous coating device as described above and a heterojunction cell, and the linear continuous coating device is used to deposit N layers of passivation films on the heterojunction cell.

[0016] The linear continuous coating method for improving the N-face field passivation effect of a heterojunction cell has the following advantages:

[0017] 1. The electromagnetic field formed by the power supply with a phase angle of 0°-180° controls the deposition area and accelerates the coating rate, and since the deposition area is controlled by the electromagnetic field, the effect of N-layer gradient doping in a single cavity is achieved, which greatly improves the process efficiency and reduces the gas loss caused by the N-type monocrystalline silicon wafer entering and leaving each cavity.

[0018] 2. The addition of the HPT power supply increases the hydrogen atom injection and etches off the unqualified surface film, thereby further improving the minority carrier lifetime.

[0019] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and achieved by the structures particularly pointed out in the description and the appended drawings.

[0020] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easier to understand, the following preferred embodiments are specifically described in detail below, together with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easier to understand, the following preferred embodiments are specifically described in detail below, together with the accompanying drawings.

[0022] Figure 1 A schematic diagram of a heterojunction battery structure related to the embodiments of the present disclosure;

[0023] Figure 2 A schematic diagram of a linear continuous coating device structure related to the embodiments of the present disclosure.

[0024] In the drawings:

[0025] 1, PECVD cavity; 21, first HPT power supply; 22, first passivation power supply; 23, second HPT power supply; 24, second passivation power supply; 25, third HPT power supply; 26, third passivation power supply; 31, first gas inlet; 32, second gas inlet; 33, third gas inlet; 34, fourth gas inlet; 35, fifth gas inlet; 36, sixth gas inlet; 4, roller; 5, carrier plate; 6, gate valve; 7, process pump. DETAILED DESCRIPTION

[0026] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easier to understand, the following preferred embodiments are specifically described in detail below, together with the accompanying drawings.

[0027] HPT refers to

[0028] PECVD refers to plasma enhanced chemical vapor deposition.

[0029] For example, Figure 1As shown, the current market N surface technical solution is: after the carrier plate enters the cavity, it is heated to about 200 degrees, H2 / SiH4 is introduced, and a certain ratio of doping gas PH3 is introduced, and a suitable power supply power is turned on for deposition. During the coating process, the carrier plate is stationary. Because the doping of N requires gradient doping, after the deposition of N1 is completed, the cavity gas is pumped clean (to prevent gas from entering the next cavity), the cavity valve is opened, the carrier plate enters the next cavity and continues to deposit N2, N3, etc. by the same method. Because the N layer needs gradient doping, multiple cavities are needed for the process, which increases the cost of equipment and the coating time, and the same cavity on the market cannot realize the entire N layer gradient doping process.

[0030] In view of the defects of the above scheme, the inventors have obtained the results after careful research and practice, and therefore the discovery process of the above problems and the solutions proposed by the present disclosure to solve the above problems should be the contribution of the inventors to the present disclosure in the process of the present disclosure.

[0031] Based on the above research, the embodiment of the present disclosure provides a linear continuous coating method for improving the N-face field passivation effect of a heterojunction battery, comprising the following steps: step S1, preset the temperature of the PECVD cavity to 200-260℃, and send the N-type monocrystalline silicon wafer into the PECVD cavity; step S2, set the phase angle of a pair of independent power sources in the HPT power supply and the passivation power supply to 0°-180°; step S3, start the first HPT power supply, pass in 1000-3000sccm of H2, set the power of the electromagnetic field to 100-500W, and set the end pressure of the PECVD cavity to 60-90Pa; step S4, start the first passivation power supply, pass in 500-2000sccm of H2, 100-300sccm of SiH4 and 50-100sccm of PH3, set the power of the electromagnetic field to 500-2000W, and obtain an N1 layer on the surface of the N-type monocrystalline silicon wafer, and set the end pressure of the PECVD cavity to 60-90Pa; step S5, start the second HPT power supply, pass in 1000-3000sccm of H2, set the power of the electromagnetic field to 100-500W, and set the end pressure of the PECVD cavity to 60-90Pa; step S6, start the second passivation power supply, pass in 500-2000sccm of H2, 100-300sccm of SiH4 and 100-300sccm of PH3, set the power of the electromagnetic field to 500-2000W, and obtain an N2 layer on the surface of the N-type monocrystalline silicon wafer, and set the end pressure of the PECVD cavity to 60-90Pa; step S7, start the third HPT power supply, pass in 1000-3000sccm of H2, set the power of the electromagnetic field to 100-500W, and set the end pressure of the PECVD cavity to 60-90Pa; step S8, start the third passivation power supply, pass in 500-2000sccm of H2, 100-300sccm of SiH4 and 100-500sccm of PH3, set the power of the electromagnetic field to 500-2000W, and obtain an N3 layer on the surface of the N-type monocrystalline silicon wafer, and set the end pressure of the PECVD cavity to 60-90Pa; step S9, send the N-layer passivated N-type monocrystalline silicon wafer out of the PECVD cavity; and step S10, perform a minority carrier lifetime test, and screen out N-layer passivated N-type monocrystalline silicon wafers with a minority carrier lifetime lower than 5000us.

[0032] In the embodiment of the present disclosure, specifically, the thickness of the N1 layer is 0.5-5nm, the thickness of the N2 layer is 0.5-5nm, and the thickness of the N3 layer is 4-15nm.

[0033] In the embodiments of the present disclosure, specifically, the power, the electromagnetic field and the phase angle are adjusted respectively to obtain the parameters and performance of the embodiment 1 and the comparative examples 1-3, which are shown in the following Tables 1-4. Table 1 is the parameters of the first HPT power supply and the first passivation power supply of the embodiment 1 and the comparative examples 1-3, Table 2 is the parameters of the second HPT power supply and the second passivation power supply of the embodiment 1 and the comparative examples 1-3, Table 3 is the parameters of the third HPT power supply and the third passivation power supply of the embodiment 1 and the comparative examples 1-3, and Table 4 is the performance test results of the embodiment 1 and the comparative examples 1-3.

[0034] Table 1

[0035]

[0036] Table 2

[0037]

[0038] Table 3

[0039]

[0040] Table 4

[0041]

[0042] In the embodiments of the present disclosure, specifically, the gas flow rate in the embodiment 1 and the comparative examples 1-3 is in units of sccm.

[0043] In the embodiments of the present disclosure, specifically, it can be known from the comparison between the embodiment 1 and the comparative examples 1 that the HPT process can effectively improve the minority carrier lifetime, but the electromagnetic field and the phase angle are still the main factors affecting the improvement of the minority carrier lifetime.

[0044] In the embodiments of the present disclosure, specifically, it can be known from the comparison between the embodiment 1 and the comparative examples 2 and 3 that without the phase angle and the electromagnetic field, a good gradient doping cannot be formed, and without field passivation, the minority carrier lifetime will be seriously reduced.

[0045] Please refer to Figure 2 , Figure 2 A linear continuous coating device is shown, which is applied to the coating of a heterojunction cell wafer by a PECVD coating equipment using a linear continuous coating method as described above. The linear continuous coating device comprises: a coating module arranged above the inside of a PECVD cavity 1, which is arranged in a manner of being separated by an HPT power supply and a passivation power supply in sequence to guide the electromagnetic field while PECVD deposition is carried out, wherein a pair of independent power supplies with a phase angle of 0°-180° are arranged in the HPT power supply and the passivation power supply; a transmission module arranged below the inside of the PECVD cavity 1, which is used to transmit a carrier plate 5 loaded with N-type monocrystalline silicon wafers through the PECVD cavity 1 by a roller 4.

[0046] In the embodiments of the present disclosure, specifically, the number of the HPT power supply and the passivation power supply is not less than three.

[0047] In the embodiments of the present disclosure, specifically, the power of the HPT power supply is 100-500 W, and the power of the passivation power supply is 500-2000 W.

[0048] In the embodiments of the present disclosure, specifically, the end of the coating module is provided with at least one process pump 7, and only one process pump is needed to control the air flow direction and pressure at the tail, without the need for a gate valve in the middle, so that the equipment cost is greatly reduced.

[0049] In the embodiments of the present disclosure, specifically, the first gas inlet 31 is suitable for carrying out vapor deposition work in the electromagnetic field range after the first HPT power supply 21 is started, the second gas inlet 32 is suitable for carrying out vapor deposition work in the electromagnetic field range after the first passivation power supply 22 is started, the third gas inlet 33 is suitable for carrying out vapor deposition work in the electromagnetic field range after the second HPT power supply 23 is started, the fourth gas inlet 34 is suitable for carrying out vapor deposition work in the electromagnetic field range after the second passivation power supply 24 is started, the fifth gas inlet 35 is suitable for carrying out vapor deposition work in the electromagnetic field range after the third HPT power supply 25 is started, and the sixth gas inlet 36 is suitable for carrying out vapor deposition work in the electromagnetic field range after the third passivation power supply 26 is started.

[0050] The embodiments of the present disclosure also provide a linear continuous coating system, which comprises the linear continuous coating device as described above, and a heterojunction cell piece, and the linear continuous coating device is used for depositing N layers of passivation films on the heterojunction cell piece.

[0051] In summary, the present application forms an electromagnetic field by using a power supply with a phase angle of 0°-180°, controls the deposition area, and accelerates the coating rate, and since the deposition area is controlled by the electromagnetic field, the effect of N-layer gradient doping in a single cavity is achieved, the process efficiency is greatly improved, and the gas loss caused by the N-type monocrystalline silicon piece entering and leaving each cavity is reduced.

[0052] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0053] The above-described embodiments according to the present application are intended to be illustrative only. Changes can be made by those skilled in the art, without departing from the scope of the present application, which is defined by the following claims. The technical scope of the present application is not limited to the above-described embodiments. The technical scope of the present application must be determined based on the scope of the claims.

Claims

1. A linear continuous coating method for improving the passivation effect of the N-plane field in heterojunction solar cells, characterized in that, Includes the following steps: The coating module is located inside the upper part of the same PECVD chamber. It performs PECVD deposition while simultaneously guiding the electromagnetic field, with the HPT power supply and passivation power supply set alternately. Step S1: Preset the temperature of the PECVD chamber to 200-260℃ and send the N-type single crystal silicon wafer into the PECVD chamber; Step S2: Set the phase angle of a pair of independent power supplies within the HPT power supply and passivation power supply to >0° and ≤180°; Step S3: Start the first HPT power supply, supply 1000-3000 sccm of H2, set the electromagnetic field power to 100-500W, and set the end pressure of the PECVD cavity to 60-90 Pa. Step S4: Start the first passivation power supply, and pass in 500-2000 sccm of H2, 100-300 sccm of SiH4 and 50-100 sccm of PH3. Set the power of the electromagnetic field to 500-2000 W to obtain an N1 layer on the surface of the N-type single crystal silicon wafer. Set the end pressure of the PECVD cavity to 60-90 Pa. Step S5: Start the second HPT power supply, supply 1000-3000 sccm of H2, set the electromagnetic field power to 100-500W, and set the end pressure of the PECVD cavity to 60-90 Pa. Step S6: Start the second passivation power supply, and pass in 500-2000 sccm of H2, 100-300 sccm of SiH4 and 100-300 sccm of PH3. Set the power of the electromagnetic field to 500-2000 W to obtain an N2 layer on the surface of the N-type single crystal silicon wafer. Set the end pressure of the PECVD cavity to 60-90 Pa. Step S7: Start the third HPT power supply, supply 1000-3000 sccm of H2, set the electromagnetic field power to 100-500W, and set the end pressure of the PECVD chamber to 60-90 Pa. Step S8: Start the third passivation power supply, and pass in 500-2000 sccm of H2, 100-300 sccm of SiH4 and 100-500 sccm of PH3. Set the power of the electromagnetic field to 500-2000 W to obtain an N3 layer on the surface of the N-type single crystal silicon wafer. Set the end pressure of the PECVD cavity to 60-90 Pa. Step S9: The N-layer passivated N-type single-crystal silicon wafer is sent out of the PECVD cavity.

2. The linear continuous coating method for improving the passivation effect of the N-plane field in heterojunction solar cells as described in claim 1, characterized in that, Also includes: Step S10: Perform minority carrier lifetime testing to screen out N-type single-crystal silicon wafers with N-layer passivation that have a minority carrier lifetime of less than 5000 µs.

3. The linear continuous coating method for improving the N-plane field passivation effect of heterojunction solar cells as described in claim 1, characterized in that, The thickness of the N1 layer is 0.5-5 nm.

4. The linear continuous coating method for improving the N-plane field passivation effect of heterojunction solar cells as described in claim 1, characterized in that, The thickness of the N2 layer is 0.5-5 nm.

5. The linear continuous coating method for improving the N-plane field passivation effect of heterojunction solar cells as described in claim 1, characterized in that, The thickness of the N3 layer is 4-15 nm.

6. A linear continuous coating apparatus, characterized in that, The linear continuous coating apparatus is used in the coating of heterojunction solar cells in a PECVD coating equipment employing the linear continuous coating method as described in any one of claims 1-5, wherein the linear continuous coating apparatus comprises: The coating module, located above the interior of the same PECVD chamber, performs PECVD deposition while simultaneously guiding the electromagnetic field, with the HPT power supply and passivation power supply arranged alternately. Both the HPT power supply and the passivation power supply are equipped with a pair of independent power supplies with a phase angle of >0° and ≤180°. The transfer module, located inside the lower part of the PECVD cavity, is used to transfer the carrier plate loaded with N-type single crystal silicon wafers through the PECVD cavity via rollers.

7. The linear continuous coating apparatus as described in claim 6, characterized in that, The number of HPT power supplies and passivation power supplies shall not be less than three.

8. The linear continuous coating apparatus as described in claim 6, characterized in that, The power of the HPT power supply is 100-500W; The passivation power supply has a power of 500-2000W.

9. The linear continuous coating apparatus as described in claim 6, characterized in that, At least one process pump is installed at the end of the coating module.

10. A linear continuous coating system, characterized in that, The invention includes a linear continuous coating apparatus as described in any one of claims 6-9, and a heterojunction solar cell, wherein the linear continuous coating apparatus is used to deposit an N-layer passivation film on the heterojunction solar cell.

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