Dielectric passivation film for reducing electro-induced degradation of PERC battery and preparation method of dielectric passivation film

A technology of electric attenuation and passivation film, which is applied in the direction of circuits, photovoltaic power generation, electrical components, etc., can solve the problems that are not suitable for industrial mass production, the reduction effect is not obvious, and the technical difficulty is large, so as to achieve enhanced passivation effect, The effect of moderate technical difficulty and high compatibility

CN110965044AInactive Publication Date: 2020-04-07ZHEJIANG AIKO SOLAR ENERGY TECH CO LTD +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2020-04-07
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a dielectric passivation film for reducing the electro-induced degradation of a PERC battery and a preparation method of the dielectric passivation film. Al2O3, SiOx and SiNx are sequentially deposited on the back surface of a silicon wafer, wherein SiNx is formed in two times, and the method comprises the following steps: introducing ammonia gas and silane into a reactionchamber at a temperature of 410-425 DEG C according to a ratio of (3-5): (0.5-2) to form a first layer SiNx with a refractive index less than 2.24%; and introducing ammonia gas and silane into a reaction chamber at a temperature of 435-445 DEG C according to a ratio of (6-7.5): (0.5-1.5) to form a second layer SiNx with a refractive index less than 2.20%, wherein the refractive index of the firstlayer SiNx is greater than that of the second layer SiNx. By the dielectric passivation film, CID can be reduced effectively; and the dielectric passivation film is low in cost and moderate in technical difficulty, and is easy for industrial mass production.
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Description

technical field

[0001] The invention relates to the manufacturing field of solar cells, in particular to a dielectric passivation film for reducing the electric attenuation of PERC cells and a preparation method thereof. Background technique

[0002] Crystalline silicon solar cells have become mainstream products in the current photovoltaic market due to their good stability and high efficiency. However, the efficiency of P-type crystalline silicon solar cells will be greatly attenuated under the condition of light or electricity, which seriously limits the further development of the industry. After exploration and research by scientists, in 1973, Fishcher et al. proposed the concept of light-induced degradation (LID), that is, the efficiency of p-type cells will be greatly attenuated after being illuminated in the actual environment, and the light-induced degradation is mainly It is manifested that the output power of photovoltaic modules drops sharply in the first few day...

Examples

Embodiment approach

[0048] The refractive index of the first layer of SiNx is 2.20%-2.24%, and the refractive index of the second layer of SiNx is 2.16%-2.19%;

[0049] Alternatively, the refractive index of the first layer of SiNx is 2.18%-2.20%, and the refractive index of the second layer of SiNx is 2.12%-2.16%;

[0050] Alternatively, the refractive index of the first layer of SiNx is 2.16%-2.19%, and the refractive index of the second layer of SiNx is 2.10%-2.14%.

[0051] Further, the silicon oxide layer is carried out in a reaction chamber with a temperature of 385-420°C, a plasma power of 5000-6500W, a pressure of 800-1200mTor, and a deposition duty ratio of (1-3): (150)ms. The nitrous oxide flow rate is 4000-5000 sccm, the silane flow rate is 100-200 sccm, and the deposition time is 210s-250s. The silicon oxide passivation layer has good compactness, which can reduce the minority carrier recombination rate on the back surface of the silicon wafer, improve the open circuit voltage and sh...

Embodiment 1

[0066] P-type monocrystalline silicon wafer (10 -16 cm -1 ), after texturing, diffusion, SE laser, etching and normal pressure annealing, PERC coating on the back, including:

[0067] (1) Deposition of Al 2 o 3 1;

[0068] (2) Deposition of SiOx 2: The SiOx 2 process is carried out in a reaction chamber with a temperature of 400°C, a plasma power of 6000W, a pressure of 1000mTor, and a deposition duty ratio of 2:150ms. is 220s-240s;

[0069] (3) Deposition of the first layer of SiNx31: The process of the first layer of SiNx31 is carried out in a reaction chamber with a temperature of 420°C, a plasma power of 5500W, a pressure of 1600mTor, and a deposition duty ratio of 2:60ms, and the ratio of ammonia gas to silane is 3.6 :0.93, refractive index 2.18%-2.20%.

[0070] (3) Deposition of the second layer of SiNx32: The process of the second layer of SiNx32 is carried out in a reaction chamber with a temperature of 440°C, a plasma power of 5500W, a pressure of 1600mTor, and ...

Embodiment 2

[0072] P-type monocrystalline silicon wafer (10 -16 cm -1 ), after texturing, diffusion, SE laser, etching and normal pressure annealing, PERC coating on the back, including:

[0073] (1) Deposition of Al 2 o 3 1;

[0074](2) Deposition of SiOx 2: The SiOx 2 process is carried out in a reaction chamber with a temperature of 400°C, a plasma power of 6000W, a pressure of 1000mTor, and a deposition duty ratio of 2:150ms. is 220s-240s;

[0075] (3) Deposition of the first layer of SiNx31: The process of the first layer of SiNx31 is carried out in a reaction chamber with a temperature of 420°C, a plasma power of 5500W, a pressure of 1600mTor, and a deposition duty ratio of 2:60ms, and the ratio of ammonia gas to silane is 3.7 :0.90, refractive index 2.16%-2.19%.

[0076] (3) Deposition of the second layer of SiNx32: The process of the second layer of SiNx32 is carried out in a reaction chamber with a temperature of 440°C, a plasma power of 5500W, a pressure of 1600mTor, and a...