Heavily-doped UMG silicon epitaxially generated high-low junction-based solar cell and preparation method

Abstract

The invention discloses a heavily-doped UMG silicon epitaxially generated high-low junction-based solar cell, which comprises a plurality of cells; and each cell is provided with an aluminium electrode layer, a first silicon nitride layer, a first silicon dioxide layer, a heavily-doped UMG silicon layer, a lightly-doped silicon epitaxy layer, a second silicon dioxide layer, a second silicon nitride layer and a plurality of heavily-doped areas from bottom to top in turn, wherein the conduction type of the lightly-doped silicon epitaxy layer is the same as that of the heavily-doped UMG silicon layer; the conduction type of the heavily-doped areas is opposite to that of the heavily-doped UMG silicon layer; and the upper surfaces of the heavily-doped areas and the upper surface of the second silicon nitride layer are provided with silver electrodes. The invention also provides a preparation method for the solar cell. A low-cost UMG silicon material is utilized, heavily-doped UMG silicon crystals are grown by the heavy doping technology, and the heavily-doped UMG silicon crystals are epitaxially grown to form a high-quality silicon film so as to prepare the solar cell, so the cost of the solar cell is much lower than that of a solar cell prepared from a high-quality silicon material directly, and the photoelectric conversion efficiency is much higher than that of a solar cell prepared from a lightly-doped UMG silicon material directly.

Description

technical field

[0001] The invention belongs to the field of solar energy applications, and in particular relates to a high-efficiency, low-cost solar cell and a preparation method based on heavily doped UMG silicon epitaxy to form high-low junctions. Background technique

[0002] Since entering the 21st century, mankind is facing a serious energy crisis. Fossil energy sources such as oil are about to be exhausted, while human demand for energy is increasing day by day. This has brought renewable energy into the spotlight. Among all renewable energy sources, solar energy is a widely distributed and inexhaustible clean energy source with great application prospects. A solar cell is a semiconductor device that converts solar energy into electrical energy, but the price of solar cells is still high at present, especially the cost of silicon solar cells, which accounts for more than 90% of the photovoltaic market, is still very high, which seriously affects the development of ...

Examples

Embodiment 1

[0069] see figure 1 , the present invention is based on heavily doped UMG silicon epitaxy to generate solar cells with high and low junctions, and the order from bottom to top is as follows:

[0070] Aluminum electrode layer 1;

[0071] a first silicon nitride layer 2;

[0072] a first silicon dioxide layer 3;

[0073] Heavy doped UMG silicon layer 4, the conductivity type of this layer can be p-type or n-type;

[0074] Lightly doped silicon epitaxial layer 5, the conductivity type of this layer is the same as the conductivity type of heavily doped UMG silicon layer 4;

[0075] second silicon dioxide layer 6;

[0076] the second silicon nitride layer 7;

[0077] Wherein in the lightly doped silicon epitaxial layer 5, there are some heavily doped regions 8 distributed near the surface of the second silicon dioxide layer 6, and the conductivity type of the heavily doped regions 8 is the same as that of the heavily doped UMG silicon layer 4. type opposite;

[0078] A silve...

Embodiment 2

[0095] According to the process of Example 1, cells of heavily doped p-type UMG solar cells were prepared, the only difference being that the raw silicon ingot was polysilicon grown by directional solidification using UMG silicon, and volume A solution with a ratio of nitric acid: hydrofluoric acid: acetic acid = 3:1:10 was used for texturing.

[0096] Wherein the mass percent concentration of nitric acid is 65%, and the mass percent concentration of hydrofluoric acid is 49%.

[0097] The efficiency of the finally obtained cell reaches 15.2% (AM1.5, light intensity 100mW / cm 2 , 25℃), no light attenuation.

Embodiment 3

[0099] see image 3 , the process of preparing heavily doped n-type UMG solar cells is as follows:

[0100] UMG silicon is grown (100) single crystal silicon by the Czochralski method to obtain the raw silicon ingot, the dopant in the raw silicon ingot is phosphorus, and the doping concentration is 2×10 20 cm -3 .

[0101] Cut the raw silicon ingot into square slices with a thickness of 150 μm; mechanically polish the slices until their surface is bright, use conventional semiconductor cleaning processes to clean, chemically polish, wash with deionized water several times, and dry with infrared lamps to obtain UMG silicon wafers .

[0102] UMG silicon wafer is used as the substrate, and lightly doped silicon epitaxial layer is grown on the surface of UMG silicon wafer by CVD technology to obtain semi-finished cells. The thickness of the lightly doped silicon epitaxial layer is 25 μm, and the dopant in the lightly doped silicon epitaxial layer is POCl 3 , with a doping conc...

technical field

[0001] The invention belongs to the field of solar energy applications, and in particular relates to a high-efficiency, low-cost solar cell and a preparation method based on heavily doped UMG silicon epitaxy to form high-low junctions. Background technique

[0002] Since entering the 21st century, mankind is facing a serious energy crisis. Fossil energy sources such as oil are about to be exhausted, while human demand for energy is increasing day by day. This has brought renewable energy into the spotlight. Among all renewable energy sources, solar energy is a widely distributed and inexhaustible clean energy source with great application prospects. A solar cell is a semiconductor device that converts solar energy into electrical energy, but the price of solar cells is still high at present, especially the cost of silicon solar cells, which accounts for more than 90% of the photovoltaic market, is still very high, which seriously affects the development of ...

Examples

Embodiment 1

[0069] see figure 1 , the present invention is based on heavily doped UMG silicon epitaxy to generate solar cells with high and low junctions, and the order from bottom to top is as follows:

[0070] Aluminum electrode layer 1;

[0071] a first silicon nitride layer 2;

[0072] a first silicon dioxide layer 3;

[0073] Heavy doped UMG silicon layer 4, the conductivity type of this layer can be p-type or n-type;

[0074] Lightly doped silicon epitaxial layer 5, the conductivity type of this layer is the same as the conductivity type of heavily doped UMG silicon layer 4;

[0075] second silicon dioxide layer 6;

[0076] the second silicon nitride layer 7;

[0077] Wherein in the lightly doped silicon epitaxial layer 5, there are some heavily doped regions 8 distributed near the surface of the second silicon dioxide layer 6, and the conductivity type of the heavily doped regions 8 is the same as that of the heavily doped UMG silicon layer 4. type opposite;

[0078] A silve...

Embodiment 2

[0095] According to the process of Example 1, cells of heavily doped p-type UMG solar cells were prepared, the only difference being that the raw silicon ingot was polysilicon grown by directional solidification using UMG silicon, and volume A solution with a ratio of nitric acid: hydrofluoric acid: acetic acid = 3:1:10 was used for texturing.

[0096] Wherein the mass percent concentration of nitric acid is 65%, and the mass percent concentration of hydrofluoric acid is 49%.

[0097] The efficiency of the finally obtained cell reaches 15.2% (AM1.5, light intensity 100mW / cm 2 , 25℃), no light attenuation.

Embodiment 3

[0099] see image 3 , the process of preparing heavily doped n-type UMG solar cells is as follows:

[0100] UMG silicon is grown (100) single crystal silicon by the Czochralski method to obtain the raw silicon ingot, the dopant in the raw silicon ingot is phosphorus, and the doping concentration is 2×10 20 cm -3 .

[0101] Cut the raw silicon ingot into square slices with a thickness of 150 μm; mechanically polish the slices until their surface is bright, use conventional semiconductor cleaning processes to clean, chemically polish, wash with deionized water several times, and dry with infrared lamps to obtain UMG silicon wafers .

[0102] UMG silicon wafer is used as the substrate, and lightly doped silicon epitaxial layer is grown on the surface of UMG silicon wafer by CVD technology to obtain semi-finished cells. The thickness of the lightly doped silicon epitaxial layer is 25 μm, and the dopant in the lightly doped silicon epitaxial layer is POCl 3 , with a doping conc...

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