阅读说明：本技术 Perc电池的背面膜层的制作方法和perc电池 (Method for manufacturing back film layer of PERC battery and PERC battery ) 是由 林纲正 方结彬 杨苏平 陈刚 于 2021-07-09 设计创作，主要内容包括：本申请适用于太阳能电池技术领域,提供了一种PERC电池的背面膜层的制作方法和PERC电池。PERC电池的背面膜层的制作方法包括：在待沉积背面膜层的电池基片上沉积氧化铝层,氧化铝层的厚度小于5nm；在沉积了氧化铝层的电池基片上沉积氮氧化硅层；在沉积了氮氧化硅层的电池基片上沉积氮化硅层和氧化硅层。如此,使得TMA耗量低,对背膜后的激光开槽工艺要求较低,背面电路与硅基体的接触电阻较低,PERC电池的光电转换效率高。(The application is suitable for the technical field of solar cells, and provides a manufacturing method of a back film layer of a PERC cell and the PERC cell. The manufacturing method of the back film layer of the PERC battery comprises the following steps: depositing an aluminum oxide layer on the battery substrate on which the back film layer is to be deposited, wherein the thickness of the aluminum oxide layer is less than 5 nm; depositing a silicon oxynitride layer on the cell substrate on which the aluminum oxide layer is deposited; and depositing a silicon nitride layer and a silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited. Therefore, TMA consumption is low, the requirements on the laser grooving process after the back film are low, the contact resistance between a back circuit and a silicon substrate is low, and the photoelectric conversion efficiency of the PERC cell is high.)

1. A method for manufacturing a back film layer of a PERC battery is characterized by comprising the following steps:

depositing an aluminum oxide layer on the battery substrate on which the back film layer is to be deposited, wherein the thickness of the aluminum oxide layer is less than 5 nm;

depositing a silicon oxynitride layer on the cell substrate on which the aluminum oxide layer is deposited;

and depositing a silicon nitride layer and a silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited.

2. The method of claim 1, wherein depositing an aluminum oxide layer on a cell substrate on which a back side film layer is to be deposited comprises:

introducing laughing gas and TMA in the tubular PECVD to form the aluminum oxide layer;

depositing a silicon oxynitride layer on the cell substrate on which the aluminum oxide layer is deposited, comprising:

introducing laughing gas and ammonia gas into the tubular PECVD to form the silicon oxynitride layer;

depositing a silicon nitride layer and a silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited, comprising:

introducing ammonia gas and silane into the tubular PECVD to form the silicon nitride layer;

and introducing laughing gas and silane into the tubular PECVD to form the silicon oxide layer.

3. The method as claimed in claim 2, wherein in the step of introducing laughing gas and TMA into the tubular PECVD to form the aluminum oxide layer, the flow rate of the laughing gas ranges from 1slm to 20slm, the flow rate of the TMA ranges from 5 seem to 300 seem, the power of the tubular PECVD ranges from 1000w to 10000w, the deposition time ranges from 5s to 100s, and the pressure ranges from 100 and 10000 mTor.

4. The method of claim 2, wherein during the step of introducing laughing gas and ammonia gas into the tubular PECVD to form the silicon oxynitride layer, the flow rate of laughing gas ranges from 1slm to 20slm, the flow rate of ammonia gas ranges from 1slm to 20slm, and the deposition duration ranges from 5s to 500 s.

5. The method of claim 2, wherein in said step of introducing ammonia gas and silane into said tubular PECVD to form said silicon nitride layer, the flow rate of ammonia gas is in the range of 1slm to 20slm, the flow rate of silane is in the range of 100 to 5000 seem, and the deposition time period is in the range of 5 to 500 s.

6. The method of claim 2, wherein during the step of introducing laughing gas and silane into the tubular PECVD to form the silicon oxide layer, a flow rate of the laughing gas ranges from 2 seem to 20 seem, a flow rate of the silane ranges from 100 seem to 5000 seem, and a deposition duration ranges from 20s to 500 s.

7. The method of claim 1, wherein depositing a silicon nitride layer and a silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited comprises:

depositing the silicon nitride layer on the cell substrate on which the silicon oxynitride layer is deposited;

depositing the silicon oxide layer on the cell substrate on which the silicon nitride layer is deposited.

8. The method of claim 1, wherein depositing a silicon nitride layer and a silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited comprises:

depositing the silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited;

depositing the silicon nitride layer on the cell substrate on which the silicon oxide layer is deposited.

9. The PERC battery is characterized by comprising a battery substrate and a back film layer arranged on the battery substrate, wherein the back film layer comprises an aluminum oxide layer, a silicon oxynitride layer, a silicon nitride layer and a silicon oxide layer, and the thickness of the aluminum oxide layer is less than 5 nm.

10. A PERC cell comprising a cell substrate and a backside film layer disposed on the cell substrate, the backside film layer being made by the method of any of claims 1-8.

Technical Field

The application belongs to the technical field of solar cells, and particularly relates to a manufacturing method of a back film layer of a PERC cell and the PERC cell.

Background

In a back film layer of the PERC cell in the related art, an aluminum oxide layer is generally thick, which results in high TMA consumption, high cost, poor ohmic contact between a back circuit and a silicon substrate, and high requirements for a laser grooving process after a back film. Therefore, how to design the back film layer of the PERC battery to reduce the cost and improve the battery quality becomes an urgent problem to be solved.

Disclosure of Invention

The application provides a manufacturing method of a back film layer of a PERC battery and the PERC battery, and aims to solve the problem of how to design the back film layer of the PERC battery so as to reduce the cost and improve the quality of the battery.

In a first aspect, the present application provides a method for manufacturing a backside film layer of a PERC cell, including:

depositing an aluminum oxide layer on the battery substrate on which the back film layer is to be deposited, wherein the thickness of the aluminum oxide layer is less than 5 nm;

depositing a silicon oxynitride layer on the cell substrate on which the aluminum oxide layer is deposited;

and depositing a silicon nitride layer and a silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited.

Optionally, depositing an aluminum oxide layer on the cell substrate on which the back side film layer is to be deposited, comprising:

introducing laughing gas and TMA in the tubular PECVD to form the aluminum oxide layer;

depositing a silicon oxynitride layer on the cell substrate on which the aluminum oxide layer is deposited, comprising:

introducing laughing gas and ammonia gas into the tubular PECVD to form the silicon oxynitride layer;

depositing a silicon nitride layer and a silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited, comprising:

introducing ammonia gas and silane into the tubular PECVD to form the silicon nitride layer;

and introducing laughing gas and silane into the tubular PECVD to form the silicon oxide layer.

Optionally, in the step of introducing laughing gas and TMA in the tubular PECVD to form the aluminum oxide layer, a flow rate of the laughing gas ranges from 1slm to 20slm, a flow rate of the TMA ranges from 5sccm to 300sccm, a power of the tubular PECVD ranges from 1000w to 10000w, a deposition time ranges from 5s to 100s, and a pressure ranges from 100-.

Optionally, in the step of introducing laughing gas and ammonia gas into the tubular PECVD to form the silicon oxynitride layer, a flow rate of the laughing gas ranges from 1slm to 20slm, a flow rate of the ammonia gas ranges from 1slm to 20slm, and a deposition duration ranges from 5s to 500 s.

Optionally, in the step of introducing ammonia gas and silane into the tubular PECVD to form the silicon nitride layer, the flow rate of ammonia gas ranges from 1slm to 20slm, the flow rate of silane ranges from 100sccm to 5000sccm, and the deposition time period ranges from 5s to 500 s.

Optionally, in the step of introducing laughing gas and silane into the tubular PECVD to form the silicon oxide layer, a flow rate of the laughing gas ranges from 2slm to 20slm, a flow rate of the silane ranges from 100sccm to 5000sccm, and a deposition duration ranges from 20s to 500 s.

Optionally, depositing a silicon nitride layer and a silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited, comprises:

depositing the silicon nitride layer on the cell substrate on which the silicon oxynitride layer is deposited;

depositing the silicon oxide layer on the cell substrate on which the silicon nitride layer is deposited.

Optionally, depositing a silicon nitride layer and a silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited, comprises:

depositing the silicon oxide layer on the cell substrate on which the silicon oxynitride layer is deposited;

depositing the silicon nitride layer on the cell substrate on which the silicon oxide layer is deposited.

In a second aspect, the present application provides a PERC battery, including a battery substrate and a back membrane layer disposed on the battery substrate, the back membrane layer includes an aluminum oxide layer, a silicon oxynitride layer, a silicon nitride layer, and a silicon oxide layer, and the thickness of the aluminum oxide layer is less than 5 nm.

In a third aspect, the PERC cell provided by the present application comprises a cell substrate and a backside film layer disposed on the cell substrate, wherein the backside film layer is manufactured by any one of the above methods.

In the method for manufacturing the back film layer of the PERC cell and the PERC cell, the thickness of the aluminum oxide layer deposited on the cell substrate is less than 5nm, so that TMA consumption is low, the requirement on a laser grooving process after the back film is low, the contact resistance between a back circuit and a silicon substrate is low, and the photoelectric conversion efficiency of the PERC cell is high.

Drawings

Fig. 1 is a schematic flow chart illustrating a method for manufacturing a backside film layer of a PERC cell according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a PERC cell according to an embodiment of the present application;

fig. 3 is a schematic flowchart of a method for manufacturing a backside film layer of a PERC cell according to an embodiment of the present application;

fig. 4 is a schematic flowchart of a method for manufacturing a back film layer of a PERC cell according to an embodiment of the present application;

fig. 5 is a schematic flowchart of a method for manufacturing a backside film layer of a PERC cell according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a PERC cell according to an embodiment of the present application.

Description of the main element symbols:

PERC cell 10, cell substrate 11, alumina layer 12, silicon oxynitride layer 13, silicon nitride layer 14, silicon oxide layer 15.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

Referring to fig. 1 and fig. 2, a method for manufacturing a back film layer of a PERC cell 10 according to an embodiment of the present application includes:

step S12: depositing an aluminum oxide layer 12 (Al) on a cell substrate 11 on which a back film layer is to be deposited₂O₃) The thickness of the alumina layer 12 is less than 5 nm;

step S13: depositing a silicon oxynitride layer 13 (SiO) on the cell substrate 11 with the deposited aluminum oxide layer 12_xN_y)；

Step S14: depositing a silicon nitride layer 14 (SiN) on the cell substrate 11 on which the silicon oxynitride layer 13 is deposited_x) And a silicon oxide layer 15 (SiO)_x)。

In the method for manufacturing the back film layer of the PERC cell 10 according to the embodiment of the present application, the thickness of the aluminum oxide layer 12 deposited on the cell substrate 11 is less than 5nm, so that TMA consumption is low, the requirements on the laser grooving process after back film processing are low, the contact resistance between the back circuit and the silicon substrate is low, and the photoelectric conversion efficiency of the PERC cell 10 is high.

It is understood that in the case where PERC cell 10 is a single-sided cell, the lower contact resistance of the back side circuitry to the silicon substrate means that the back electric field and the contact resistance of the back electrode to the silicon substrate are lower. In the case where the PERC cell 10 is a double-sided cell, the contact resistance between the back surface circuit and the silicon substrate is low, which means that the contact resistance between the back gate line and the silicon substrate is low.

Specifically, the thickness of the aluminum oxide layer 12 is, for example, 0.58nm, 0.9nm, 1nm, 1.2nm, 1.7nm, 2nm, 2.5nm, 2.8nm, 3nm, 3.6nm, 4nm, 4.2nm, 4.8nm, 4.9 nm. The specific value of the thickness of the alumina layer 12 is not limited as long as the foregoing range is satisfied.

Specifically, the morphology of the aluminum oxide layer 12 is a discontinuous island population. Therefore, the alumina layers 12 of the non-continuous island groups are uniformly distributed on the silicon chip, so that the passivation effect of the back of the battery is effectively achieved, the use amount of TMA is reduced to a certain extent, and the manufacturing cost can be reduced.

Specifically, before step S12, texturing, boron diffusion, SE laser, etching, and annealing may be performed on the P-type single crystal silicon wafer, thereby forming the cell substrate 11 on which the back film layer is to be deposited. The cell substrate 11 with the back side film layer to be deposited may then be placed in a coating apparatus to deposit a passivation film. In other embodiments, the aforementioned process may be performed on an N-type silicon wafer or a polycrystalline silicon wafer to form the cell substrate 11 on which the back film layer is to be deposited. And are not limited herein.

In this embodiment, the coating apparatus may be a Plasma Enhanced Chemical Vapor Deposition (PECVD) apparatus. Therefore, the basic temperature required during film coating is low, the deposition rate is high, the efficiency is high, the number of formed passivation film pinholes is small, cracking is not easy to occur, the quality is good, and the improvement of the production efficiency and the battery performance is facilitated.

In the present embodiment, after step S14, the cell substrate 11 on which the aluminum oxide layer 12, the silicon oxynitride layer 13, the silicon nitride layer 14, and the silicon oxide layer 15 are deposited may be taken out of the tube PECVD. After step S14, the cell substrate 11 on which the aluminum oxide layer 12, the silicon oxynitride layer 13, the silicon nitride layer 14, and the silicon oxide layer 15 are deposited may be subjected to front-side plating, back-side laser, and screen printing to produce the PERC cell 10.

In this embodiment, the front surface of the cell substrate 11 may be plated with a silicon oxide layer. Further, the cell substrate 11 may be subjected to an annealing treatment by thermal oxidation to form a silicon oxide layer. Thus, the recombination of the carriers at the surface can be effectively prevented, the conversion efficiency of the PERC cell 10 is improved, the PID resistance of the PERC cell 10 is improved, and the service life is prolonged.

In this embodiment, the front surface of the cell substrate 11 may be plated with a silicon nitride layer. This reduces the reflectance of the PERC cell 10 to sunlight, and is advantageous for improving the photoelectric conversion efficiency of the PERC cell 10.

In the present embodiment, back-surface grooving may be performed using a laser, a back electrode may be formed by screen printing using silver paste on the grooved battery substrate 11, a back electric field may be formed by screen printing using aluminum paste, and a front electrode may be formed by screen printing using silver paste. The printed battery substrate 11 is then sintered. Thus, the recombination rate of the surface can be reduced by the back electric field, the back surface can be passivated, and current can be output through the front electrode and the back electrode.

It will be appreciated that in other embodiments, the electrodes may be fabricated by depositing metal using a mask. The specific manner of fabricating the electrodes is not limited herein.

Additionally, the resulting PERC cell 10 may be subjected to electrical performance testing. In this manner, the performance of PERC cell 10 may be tested, facilitating timely troubleshooting and improvement.

Referring to fig. 3, optionally, step S12 includes:

step S121: nitrous oxide (N) is introduced into the tubular PECVD₂O, nitrous oxide) and TMA (trimethylaluminum) to form an aluminum oxide layer 12;

step S13 includes:

step S131: laughing gas and ammonia (NH) gas are introduced into the tubular PECVD₃) To form a silicon oxynitride layer 13;

step S14 includes:

step S141: introducing ammonia (NH) into the tubular PECVD₃) And Silane (SiH)₄) To form a silicon nitride layer 14;

step S142: laughing gas and silane were passed in the tubular PECVD to form the silicon oxide layer 15.

Therefore, the aluminum oxide layer 12, the silicon oxynitride layer 13, the silicon nitride layer 14 and the silicon oxide layer 15 are deposited by introducing gas in the tubular PECVD, so that the efficiency is high, the film forming quality is good, and the improvement of the quality of the PERC battery 10 is facilitated.

Specifically, before step S121, the method comprises: the gas in the tubular PECVD is evacuated. Thus, the influence of the residual gas in the tubular PECVD process on the subsequent deposition of the aluminum oxide layer 12 is avoided, which is beneficial to improving the quality of the PERC cell 10.

Specifically, before step S131, the method includes: laughing gas and TMA in tubular PECVD were evacuated. Therefore, the influence of residual laughing gas and TMA in the tubular PECVD on the subsequent deposition process of the silicon oxynitride layer 13 is avoided, and the improvement of the quality of the PERC cell 10 is facilitated.

Specifically, before step S141, the method includes: laughing gas and ammonia gas in the tubular PECVD were evacuated. Thus, the influence of residual laughing gas and ammonia gas in the tubular PECVD on the subsequent process of depositing the silicon nitride layer 14 is avoided, and the improvement of the quality of the PERC cell 10 is facilitated.

Specifically, before step S151, the method includes: the ammonia and silane in the tubular PECVD are evacuated. Therefore, the influence of residual ammonia gas and silane in the tubular PECVD on the subsequent process of depositing the silicon oxide layer 15 is avoided, and the quality of the PERC cell 10 is improved.

Note that in the example of fig. 3, step S141 is performed first, and then step S142 is performed. In other words, the silicon nitride layer 14 is deposited first, followed by the silicon oxide layer 15. It is understood that in other examples, step S142 may be performed first, and then step S141 may be performed. In other words, the silicon oxide layer 15 is deposited first, and then the silicon nitride layer 14 is deposited. The order of step S141 and step S142 is not limited herein.

Optionally, in step S121, the flow rate of laughing gas ranges from 1slm to 20slm, the flow rate of TMA ranges from 5sccm to 300sccm, the power of the tubular PECVD ranges from 1000w to 10000w, the deposition duration ranges from 5S to 100S, and the pressure ranges from 100 to 10000 mTor.

In this way, the aluminum oxide layer 12 is deposited by limiting the range of each parameter in step S121, so that the aluminum oxide layer 12 has good quality and small thickness.

Specifically, the flow rate of laughing gas is, for example, 1slm, 2slm, 8slm, 10slm, 12slm, 15slm, 18slm, 19slm, 20 slm. TMA flow rates are, for example, 5sccm, 6sccm, 17sccm, 26sccm, 45sccm, 66sccm, 97sccm, 116sccm, 135sccm, 176sccm, 217sccm, 246sccm, 288sccm, 300 sccm. The power of the tubular PECVD is, for example, 1000w, 1010w, 1500w, 2000w, 2300w, 3800w, 5000w, 6500w, 7800w, 8000w, 9500w, 10000 w. The deposition time period is, for example, 5s, 6s, 12s, 20s, 35s, 46s, 52s, 60s, 77s, 82s, 92s, 98s, 100 s. The pressure is, for example, 100mTor, 110mTor, 830mTor, 1250mTor, 2400mTor, 3510mTor, 5630mTor, 8750mTor, 9800mTor, 10000 mTor.

Preferably, the flow rate of laughing gas is in the range of 15slm to 20 slm. For example, 15slm, 17slm, 18slm, 19slm, 20 slm. This is advantageous in further improving the quality of the alumina layer 12.

Preferably, the flow rate of TMA ranges from 5sccm to 245 sccm. Such as 5sccm, 6sccm, 17sccm, 26sccm, 45sccm, 66sccm, 97sccm, 116sccm, 135sccm, 176sccm, 217sccm, 245 sccm. This is advantageous in further improving the quality of the alumina layer 12, further reducing the amount of TMA used, and in reducing the cost.

Preferably, the power of the tubular PECVD is in the range of 6000w-10000 w. For example, 6000w, 6500w, 7800w, 8000w, 9500w, 10000 w. In this way, the quality of the alumina layer 12 can be further improved.

Preferably, the deposition time period ranges from 60s to 100 s. For example, 60s, 63s, 77s, 82s, 92s, 98s, and 100 s. This is advantageous in further improving the quality of the alumina layer 12.

Preferably, the pressure is in the range of 300-10000 mTor. For example, 300mTor, 320mTor, 830mTor, 1250mTor, 2400mTor, 3510mTor, 5630mTor, 8750mTor, 9800mTor, 10000 mTor. This is advantageous in further improving the quality of the alumina layer 12.

Optionally, in step S131, the flow rate of laughing gas ranges from 1slm to 20slm, the flow rate of ammonia gas ranges from 1slm to 20slm, and the deposition duration ranges from 5S to 500S.

In this way, by limiting the range of each parameter in step S131, the deposition of the silicon oxynitride layer 13 is achieved, so that the quality of the silicon oxynitride layer 13 is better.

Specifically, the flow rate of laughing gas is, for example, 1slm, 2slm, 8slm, 10slm, 12slm, 15slm, 18slm, 19slm, 20 slm. The flow rate of ammonia gas is, for example, 1slm, 2slm, 8slm, 10slm, 12slm, 15slm, 18slm, 19slm, or 20 slm. The deposition time is, for example, 5s, 6s, 12s, 80s, 135s, 146s, 222s, 360s, 477s, 482s, 492s, 500 s.

Preferably, the flow rate of laughing gas is in the range of 17slm to 20 slm. For example 17slm, 18slm, 19slm, 20 slm. This is advantageous in further improving the quality of the silicon oxynitride layer 13.

Preferably, the flow rate of ammonia is in the range of 6slm to 20 slm. For example, 6slm, 8slm, 10slm, 12slm, 15slm, 18slm, 19slm, 20 slm. This is advantageous in further improving the quality of the silicon oxynitride layer 13.

Preferably, the deposition time period ranges from 300s to 500 s. For example 300s, 360s, 477s, 482s, 492s, 500 s. This is advantageous in further improving the quality of the silicon oxynitride layer 13.

Alternatively, in step S141, the flow rate of ammonia gas ranges from 1slm to 20slm, the flow rate of silane ranges from 100sccm to 5000sccm, and the deposition time period ranges from 5S to 500S.

In this way, by limiting the range of each parameter in step S141, the deposition of the silicon nitride layer 14 is achieved, so that the quality of the silicon nitride layer 14 is better.

Specifically, the flow rate of ammonia gas is, for example, 1slm, 2slm, 8slm, 10slm, 12slm, 15slm, 18slm, 19slm, or 20 slm. The flow rate of silane is, for example, 100sccm, 110sccm, 500sccm, 850sccm, 1210sccm, 2420sccm, 3550sccm, 4210sccm, 4850sccm, 5000 sccm. The deposition time is, for example, 5s, 6s, 12s, 80s, 135s, 146s, 222s, 360s, 477s, 482s, 492s, 500 s.

Preferably, the flow rate of ammonia is in the range of 16slm to 20 slm. For example, 16slm, 18slm, 19slm, 20 slm. This is advantageous in further improving the quality of the silicon nitride layer 14.

Preferably, the flow rate of silane ranges from 1200sccm to 5000 sccm. Such as 1200sccm, 1300sccm, 1850sccm, 1210sccm, 2420sccm, 3550sccm, 4210sccm, 4850sccm, 5000 sccm. This is advantageous in further improving the quality of the silicon nitride layer 14.

Preferably, the deposition time period ranges from 5s to 280 s. For example, 5s, 6s, 12s, 80s, 135s, 146s, 222s, 280 s. This is advantageous in further improving the quality of the silicon nitride layer 14.

Optionally, in step S142, the flow rate of the laughing gas ranges from 2slm to 20slm, the flow rate of the silane ranges from 100sccm to 5000sccm, and the deposition time period ranges from 20S to 500S.

In this way, the silicon oxide layer 15 is deposited by limiting the range of each parameter in step S142, so that the quality of the silicon oxide layer 15 is better.

Specifically, the flow rate of laughing gas is, for example, 2slm, 8slm, 10slm, 12slm, 15slm, 18slm, 19slm, 20 slm. The flow rate of silane is, for example, 100sccm, 110sccm, 500sccm, 850sccm, 1210sccm, 2420sccm, 3550sccm, 4210sccm, 4850sccm, 5000 sccm. The deposition time is, for example, 20s, 23s, 36s, 80s, 135s, 146s, 222s, 360s, 477s, 482s, 492s, 500 s.

Preferably, the flow rate of laughing gas is in the range of 10slm to 20 slm. The flow rate of laughing gas is, for example, 10slm, 12slm, 15slm, 18slm, 19slm, 20 slm. This is advantageous in further improving the quality of the silicon oxide layer 15.

Preferably, the flow rate of silane ranges from 2000sccm to 5000 sccm. Such as 2000sccm, 2210sccm, 2420sccm, 3550sccm, 4210sccm, 4850sccm, 5000 sccm. This is advantageous in further improving the quality of the silicon oxide layer 15.

Preferably, the deposition time period ranges from 200s to 500 s. For example 200s, 222s, 360s, 477s, 482s, 492s, 500 s. This is advantageous in further improving the quality of the silicon oxide layer 15.

Referring to fig. 4 and fig. 2, optionally, step S14 includes:

step S143: depositing a silicon nitride layer 14 on the cell substrate 11 on which the silicon oxynitride layer 13 is deposited;

step S144: a silicon oxide layer 15 is deposited on the cell substrate 11 on which the silicon nitride layer 14 is deposited.

In this manner, the silicon nitride layer 14 is deposited first, and then the silicon oxide layer 15 is deposited, thereby achieving deposition of the silicon nitride layer 14 and the silicon oxide layer 15. Therefore, a deposition mode of the silicon nitride layer 14 and the silicon oxide layer 15 is provided, which can be selected according to the specific conditions of the subsequent back laser, so as to achieve the optimal slotting morphology, ensure that the silicon substrate and the aluminum paste form good contact, and simultaneously play a good protection role for the aluminum oxide layer 13.

Referring to fig. 5 and 6, optionally, step S14 includes:

step S145: depositing a silicon oxide layer 15 on the cell substrate 11 on which the silicon oxynitride layer 13 is deposited;

step S146: a silicon nitride layer 14 is deposited on the cell substrate 11 on which the silicon oxide layer 15 is deposited.

In this manner, the silicon oxide layer 15 is deposited first, and then the silicon nitride layer 14 is deposited, thereby achieving deposition of the silicon nitride layer 14 and the silicon oxide layer 15. Therefore, a deposition mode of the silicon nitride layer 14 and the silicon oxide layer 15 is provided, which can be selected according to the specific conditions of the subsequent back laser, so as to achieve the optimal slotting morphology, ensure that the silicon substrate and the aluminum paste form good contact, and simultaneously play a good protection role for the aluminum oxide layer 13.

The PERC battery 10 of the embodiment of the application comprises a battery substrate 11 and a back film layer arranged on the battery substrate 11, wherein the back film layer comprises an aluminum oxide layer 12, a silicon oxynitride layer 13, a silicon nitride layer 14 and a silicon oxide layer 15, and the thickness of the aluminum oxide layer 12 is smaller than 5 nm.

The PERC cell 10 of the embodiment of the present application includes a cell substrate 11 and a back film layer disposed on the cell substrate 11, and the back film layer is manufactured by any one of the above methods.

According to the PERC cell 10, the thickness of the aluminum oxide layer 12 deposited on the cell substrate 11 is smaller than 5nm, so that TMA consumption is low, the requirement on a laser grooving process after back film is low, the contact resistance between a back circuit and a silicon substrate is low, and the photoelectric conversion efficiency of the PERC cell 10 is high.

For explanation and explanation of PERC cell 10, reference is made to the foregoing description, and further description is omitted here to avoid redundancy.

The following table is a table comparing the performance of the PERC cell in the related art and the PERC cell of the example of the present application.

Process for the preparation of a coating

Thickness of aluminum oxide layer

Consumption of TMA

UOC

ISC

RS

EFF

This application

2nm

1mg

688mV

13.58A

2.10mΩ

22.97％

Related art

6nm

4mg

688 mV

13.57A

2.19mΩ

22.94％

Obviously, compared with the related art, the PERC cell according to the embodiment of the present application reduces the thickness of the aluminum oxide layer, reduces TMA consumption, increases short-circuit current, reduces resistance, and increases photoelectric conversion efficiency under the condition that the open-circuit voltage is kept flat.

The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed.