阅读说明：本技术 一种网状射频pecvd电极结构及其应用方法 (Mesh radio frequency PECVD electrode structure and application method thereof ) 是由 张超雄 王铭 汪涛 凌俊 郭小勇 易治凯 于 2021-01-21 设计创作，主要内容包括：本发明涉及的一种网状射频PECVD电极结构,它包括网状电极板(1)本体,所述网状电极板(1)采用9*12的网框结构,在横向每隔四个网格设置一个RF功率馈入点(2),纵向每隔三个网格设置一个RF功率馈入点(2)。所述网状电极板(1)的长度为1.95m,宽度为1.60m。所述网状电极板(1)的内网框直径为5cm,外网框直径为7cm。本发明使用网状的电极结构,同时解决射频PECVD工艺腔的边缘效应和电势驻波效应对电磁场均匀性的影响,改善非晶硅的镀膜效果,提高了太阳能电池的转换效率和产品良率,同时稳定的工艺更适合运用于量产。(The invention relates to a reticular radio frequency PECVD electrode structure, which comprises a reticular electrode plate (1) body, wherein the reticular electrode plate (1) adopts a 9 x 12 net frame structure, an RF power feed-in point (2) is arranged every other four grids in the transverse direction, and an RF power feed-in point (2) is arranged every other three grids in the longitudinal direction. The length of the reticular electrode plate (1) is 1.95m, and the width of the reticular electrode plate is 1.60 m. The diameter of an inner net frame of the reticular electrode plate (1) is 5cm, and the diameter of an outer net frame is 7 cm. The invention uses the reticular electrode structure, simultaneously solves the influence of the edge effect and the potential standing wave effect of the radio frequency PECVD process cavity on the uniformity of an electromagnetic field, improves the film coating effect of amorphous silicon, improves the conversion efficiency and the product yield of the solar cell, and simultaneously, the stable process is more suitable for mass production.)

1. A kind of netted radio frequency PECVD electrode structure, characterized by: the grid electrode plate comprises a grid electrode plate body (1), wherein the grid electrode plate body (1) adopts a 9 x 12 grid frame structure, an RF power feed-in point (2) is arranged every other four grids in the transverse direction, and an RF power feed-in point (2) is arranged every other three grids in the longitudinal direction.

2. The RF PECVD electrode structure of claim 1, wherein: the length of the reticular electrode plate (1) is 1.95m, and the width of the reticular electrode plate is 1.60 m.

3. The RF PECVD electrode structure of claim 1, wherein: the diameter of an inner net frame of the reticular electrode plate (1) is 5cm, and the diameter of an outer net frame is 7 cm.

4. A method of applying the mesh rf PECVD electrode structure of claim 1, comprising:

s1, texturing and cleaning an N-type monocrystalline silicon wafer with the size of 156.75 mm;

s2, performing amorphous silicon deposition by using a plate-type radio frequency plasma enhanced chemical vapor deposition method;

s3, using a mesh electrode plate (1), and depositing for 3 min; the reticular electrode plate (1) adopts a 9-12 mesh frame structure, one RF power feed-in point (2) is arranged every other four transverse grids, and one RF power feed-in point (2) is arranged every other three longitudinal grids;

s4, the thickness of the deposited amorphous silicon film is measured using an ellipsometer.

5. The method of claim 4, wherein the applying step comprises: the length of the reticular electrode plate (1) is 1.95m, the width of the reticular electrode plate is 1.60m, the diameter of the inner net frame is 5cm, and the diameter of the outer net frame is 7 cm.

6. The method of claim 4, wherein the applying step comprises: the technical scheme is that the reticular electrode plate (1) is arranged in a process cavity (3), each RF power feed-in point (2) is respectively connected with an RF power supply, a gas distribution system (5) is arranged below the reticular electrode plate (1), a lower electrode plate (8) is arranged below the gas distribution system (5), a graphite carrier plate (7) is arranged on the lower electrode plate (8), the gas distribution system (5) is connected with a gas inlet (6), and a gas outlet (9) is arranged at the bottom of the process cavity (3).

Technical Field

The invention relates to the technical field of high-efficiency cell manufacturing in the photovoltaic industry, in particular to a reticular radio frequency PECVD electrode structure and an application method thereof.

Background

With the wide application of solar energy, the solar photovoltaic panel industry is also developed vigorously, and a high silicon-based Heterojunction (HJT) cell is a third-generation solar cell which has the most development potential after high-efficiency PERC, has the characteristics of high conversion efficiency, high open-circuit voltage, low temperature coefficient, no light induced attenuation (LID), no induced attenuation (PID), low process temperature, high double-sided rate and the like, and has very important significance for the purposes of achieving carbon peak reaching in 2030 and realizing carbon neutralization in 2060 in China.

As a key process of the HJT battery, the PECVD can prepare an amorphous silicon film to form a built-in electric field, so that the transport of photon-generated carriers is accelerated. Therefore, the product yield, the conversion efficiency and the service life of the solar cell are seriously influenced by the coating uniformity of the PECVD. At present, the nonuniformity of electromagnetic field distribution in the plate-type PECVD process cavity mainly comes from the edge effect, the potential standing wave effect, the skin effect and the like of the electrode, and the influence of the factors on the electromagnetic field uniformity is changed along with the change of the frequency of the electrode. For a Radio Frequency (RF) power supply used for large-scale production of HJT batteries, the frequency is 13.98MHz, and the edge effect and the potential standing wave effect are the main factors influencing the coating uniformity.

The edge effect means that the electric field lines extend from the area between the polar plates to the external space due to the limitation of the shape of the electrode, and the electric field lines are changed into open distribution from parallel lines, thereby influencing the coating uniformity of the edge part. The potential standing wave effect means that an electromagnetic field of plasma collides with a polar plate boundary in the process of propagation and propagates from the polar plate boundary to the interior of the plasma, and when the wavelength of the electromagnetic wave is close to the size of the cavity, the electric field is superposed in the center of the polar plate, so that the ionization rate of central gas is far greater than that of the edge part. For these electromagnetic effects, the mainstream solution at present is to use a multi-point feeding technique in combination with a trapezoidal electrode design, so as to greatly reduce the influence of the edge effect and the potential standing wave effect on the edge of the PECVD carrier plate and the coating uniformity of the internal cell.

However, due to the shape limitation of the trapezoid electrode, the uniformity of the coating of the edge carrier plate perpendicular to the trapezoid direction is not improved well. Meanwhile, due to structural limitation, the RF power feed point can only be connected to the electrode perpendicular to the trapezoid, so that the improvement of the standing wave effect of the potential of the trapezoid electrode by multi-point feeding is not perfect. Therefore, there is a need for a plate design that addresses both the edge effect and the potential standing wave effect of a RF PECVD process chamber.

Disclosure of Invention

The invention aims to overcome the defects and provide a mesh-shaped radio frequency PECVD electrode structure, which is used for solving the problem of poor uniformity of an amorphous silicon film caused by edge effect and potential standing wave effect in the PECVD process of an HJT battery.

The purpose of the invention is realized as follows:

a reticular radio frequency PECVD electrode structure comprises a reticular electrode plate body, wherein the reticular electrode plate adopts a 9 x 12 net frame structure, an RF power feed-in point is arranged every other four transverse grids, and an RF power feed-in point is arranged every other three longitudinal grids.

A mesh radio frequency PECVD electrode structure, the length of mesh electrode board is 1.95m, and the width is 1.60 m.

The mesh radio frequency PECVD electrode structure is characterized in that the diameter of an inner mesh frame of a mesh electrode plate is 5cm, and the diameter of an outer mesh frame of the mesh electrode plate is 7 cm.

An application method of a mesh radio frequency PECVD electrode structure comprises the following contents:

s1, texturing and cleaning an N-type monocrystalline silicon wafer with the size of 156.75 mm;

s2, performing amorphous silicon deposition by using a plate-type radio frequency plasma enhanced chemical vapor deposition method;

s3, using a mesh electrode plate, and depositing for 3 min; the reticular electrode plate adopts a 9-by-12 net frame structure, an RF power feed-in point is arranged every other four grids in the transverse direction, and an RF power feed-in point is arranged every other three grids in the longitudinal direction;

s4, the thickness of the deposited amorphous silicon film is measured using an ellipsometer.

An application method of a mesh radio frequency PECVD electrode structure is characterized in that the length of a mesh electrode plate is 1.95m, the width of the mesh electrode plate is 1.60m, the diameter of an inner mesh frame is 5cm, and the diameter of an outer mesh frame is 7 cm.

The application method of the reticular radio frequency PECVD electrode structure is characterized in that the reticular electrode plate is arranged in a process cavity, each RF power feed-in point is respectively connected with an RF power supply, a gas distribution system is arranged below the reticular electrode plate, a lower polar plate is arranged below the gas distribution system, a graphite carrier plate is arranged on the lower polar plate, the gas distribution system is connected with a gas inlet, and a gas outlet is arranged at the bottom of the process cavity.

Compared with the prior art, the invention has the beneficial effects that:

the invention uses the reticular electrode structure, and the reticular structure has a relatively symmetrical structure, so compared with a trapezoidal structure, the invention has more reasonable structure on the vertical and horizontal edges, more perfectly matches with the multi-point feed-in technology, and reduces the influence of the transverse edge effect on the uniformity of the coating film; meanwhile, the influence of the edge effect and the potential standing wave effect of the radio frequency PECVD process cavity on the uniformity of an electromagnetic field is solved, the film coating effect of amorphous silicon is improved, the conversion efficiency and the product yield of the solar cell are improved, and meanwhile, the stable process is more suitable for mass production.

Drawings

Fig. 1 is a schematic structural diagram of embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of an application of embodiment 1 of the present invention.

FIG. 3 is a schematic structural view of comparative example 1 of the present invention.

Wherein:

the device comprises a reticular electrode plate 1, an RF power feed-in point 2, a process cavity 3, a trapezoidal electrode plate 4, a gas distribution system 5, a gas inlet 6, a graphite carrier plate 7, a lower electrode plate 8 and a gas outlet 9.

Detailed Description

For a better understanding of the technical aspects of the present invention, reference will now be made in detail to the accompanying drawings. It should be understood that the following specific examples are not intended to limit the embodiments of the present invention, but are merely exemplary embodiments of the present invention. It should be noted that the description of the positional relationship of the components, such as the component a is located above the component B, is based on the description of the relative positions of the components in the drawings, and is not intended to limit the actual positional relationship of the components.

Example 1:

referring to fig. 1, the invention relates to a mesh-shaped radio frequency PECVD electrode structure, which comprises a mesh-shaped electrode plate 1 body, wherein the mesh-shaped electrode plate 1 is designed by adopting a 9 x 12 mesh frame, the length is 1.95m, the width is 1.60m, the diameter of the inner mesh frame is 5cm, and the diameter of the outer mesh frame is 7 cm.

One RF power feed point 2 is provided every fourth grid in the transverse direction, and one RF power feed point 2 is provided every third grid in the longitudinal direction. This multi-point feeding scheme is equivalent to dividing the grid electrode plate 1 into nine equal-sized small blocks, and applying RF power to these small block areas can greatly reduce the influence of the potential standing wave effect. Meanwhile, compared with a trapezoidal electrode, the screen frame design can reduce the influence of the transverse edge effect on the uniformity of the coated film.

Referring to fig. 2, the application method of a mesh-type rf PECVD electrode structure according to the present invention comprises the following steps:

s1, texturing and cleaning an N-type monocrystalline silicon wafer (180 mu m) with the size of 156.75 mm;

s2, performing amorphous silicon deposition by using a plate type radio frequency plasma enhanced chemical vapor deposition method (RF-PECVD);

s3, using the mesh electrode plate 1, and depositing for 3 min; the reticular electrode plate 1 is designed by adopting a 9-12 mesh frame, the length is 1.95m, the width is 1.60m, the diameter of the inner mesh frame is 5cm, and the diameter of the outer mesh frame is 7 cm;

s4, the thickness of the deposited amorphous silicon film is measured using an ellipsometer.

The reticular electrode plate 1 is arranged in the process cavity 3, each RF power feed-in point 2 is respectively connected with an RF power supply, a gas distribution system 5 is arranged below the reticular electrode plate 1, a lower electrode plate 8 is arranged below the gas distribution system 5, a graphite carrier plate 7 is arranged on the lower electrode plate 8, the gas distribution system 5 is connected with a gas inlet 6, and a gas outlet 9 is arranged at the bottom of the process cavity 3.

Comparative example 1:

referring to fig. 3, the difference of comparative example 1 with respect to example 1 is that the comparative example 1 employs a trapezoidal polar plate 4, the trapezoidal polar plate 4 and a gas distribution system 5 are disposed in a process chamber 3, four end points in the middle of the trapezoidal polar plate 4 in the vertical direction are respectively connected to an RF power supply, the gas distribution system 5 is disposed below the trapezoidal polar plate 4, a lower polar plate 8 is disposed below the gas distribution system 5, a graphite carrier plate 7 is disposed on the lower polar plate 8, the gas distribution system 5 is connected to a gas inlet 6, and a gas outlet 9 is disposed at the bottom of the process chamber 3.

The application method of comparative example 1 includes the following:

s1, texturing and cleaning an N-type monocrystalline silicon wafer (180 mu m) with the size of 156.75 mm;

s2, performing amorphous silicon deposition by using a plate type radio frequency plasma enhanced chemical vapor deposition method (RF-PECVD);

s3, using a trapezoidal multi-point feed electrode, and depositing for 3 min;

s4, the thickness of the deposited amorphous silicon film is measured using an ellipsometer.

The amorphous silicon film thicknesses obtained in comparative example 1 and example 1 were compared in the following table:

compared with the conventional HJT cell preparation method in comparative example 1, the amorphous silicon film obtained by using the mesh electrode used in example 1 has more uniform thickness, which fully shows that the mesh electrode can provide more uniform electromagnetic field.

The above is only a specific application example of the present invention, and the protection scope of the present invention is not limited in any way. All the technical solutions formed by equivalent transformation or equivalent replacement fall within the protection scope of the present invention.