Low-pressure diffusion process for solar monocrystalline high-efficiency perc+se cells

Abstract

The present invention relates to the field of solar cell production diffusion. A low-pressure diffusion process for solar single crystal high-efficiency PERC+SE cells, comprising the following steps: high-temperature oxidation before diffusion, preparation of PN junction by a step-by-step diffusion method, and post-oxidation, wherein the preparation of PN junction by the step-by-step diffusion method includes a first step of low-pressure diffusion , heat preservation and buffering, the second step of low-pressure diffusion, the first step of temperature rise and the second step of temperature rise and promotion; the present invention can obtain high surface concentration and low junction depth, and the electrical performance parameters are shown as low open circuit voltage and filling, short circuit current Higher, so that the short-wave effect is poor after the module is packaged, thereby showing a low CTM (percentage of the output power of the module and the sum of the power of the cell), and the cell efficiency of the present invention is greatly improved.

Description

technical field

[0001] The present invention relates to the field of solar cell production diffusion. Background technique

[0002] With global warming, various renewable energy sources are developing rapidly. Among them, photovoltaics, as an important renewable energy source, have developed rapidly in the past fifteen years, and various types of batteries have blossomed. Among them, single-crystal high-efficiency PERC+SE batteries have initially achieved grid parity, making important contributions to the development of global new energy.

[0003] The core step in the production of solar cells is to prepare a PN junction, and the diffusion-prepared PN junction method is to use a heating method to incorporate V group impurities into P-type silicon or group III impurities into N-type silicon. The impurity element enters the silicon matrix due to thermal diffusion movement at high temperature, and its distribution in the matrix depends on the type of impurity element, initial ...

Examples

Embodiment 1

[0019] High temperature oxidation before diffusion: silicon wafer is oxidized at high temperature, and a layer of nanometer-thick SiO2 is pre-grown on the surface of the silicon wafer;

[0020] The process parameters are as follows: the pressure in the furnace is 110 mbar, the oxidation step time is maintained for 150 s, the flow rate of oxygen gas is 6000 sccm, the flow rate of nitrogen gas is 500 sccm to 2000 sccm, and the temperature is 750 ℃.

[0021] Low-pressure diffusion: The PN junction is prepared by a step-by-step diffusion method. The specific diffusion steps are as follows:

[0022] The first step of low-pressure diffusion, the process parameters are: the furnace pressure is 110 mbar, the diffusion temperature is 775 ℃; the diffusion time is 185 s; the nitrogen flow rate is 1200sccm; the phosphorus oxychloride flow rate is 900sccm; the oxygen flow rate is 700sccm;

[0023] Insulation buffer, the process conditions are: the pressure is 110mbar, the diffusion tempera...

Embodiment 2

[0030] High temperature oxidation before diffusion: silicon wafer is oxidized at high temperature, and a layer of nanometer-thick SiO2 is pre-grown on the surface of the silicon wafer;

[0031] The process parameters are as follows: the pressure in the furnace is 110 mbar, the oxidation step time is maintained for 150 s, the flow rate of oxygen gas is 6000 sccm, the flow rate of nitrogen gas is 500 sccm to 2000 sccm, and the temperature is 750 ℃.

[0032] Low-pressure diffusion: The PN junction is prepared by a step-by-step diffusion method. The specific diffusion steps are as follows:

[0033] The first step of low-pressure diffusion, the process parameters are: the furnace pressure is 110 mbar, the diffusion temperature is 775 ℃; the diffusion time is 185 s; the nitrogen flow rate is 1200sccm; the phosphorus oxychloride flow rate is 900sccm; the oxygen flow rate is 700sccm;

[0034] Insulation buffer, the process conditions are: the pressure is 110mbar, the diffusion tempera...

Embodiment 3

[0041] High temperature oxidation before diffusion: silicon wafer is oxidized at high temperature, and a layer of nanometer-thick SiO2 is pre-grown on the surface of the silicon wafer;

[0042]The process parameters are as follows: the pressure in the furnace is 110 mbar, the oxidation step time is maintained for 150 s, the flow rate of oxygen gas is 6000 sccm, the flow rate of nitrogen gas is 500 sccm to 2000 sccm, and the temperature is 750 ℃.

[0043] Low-pressure diffusion: The PN junction is prepared by a step-by-step diffusion method. The specific diffusion steps are as follows:

[0044] The first step of low-pressure diffusion, the process parameters are: the furnace pressure is 110 mbar, the diffusion temperature is 775 ℃; the diffusion time is 185 s; the nitrogen flow rate is 1200sccm; the phosphorus oxychloride flow rate is 900sccm; the oxygen flow rate is 700sccm;

[0045] Insulation buffer, the process conditions are: the pressure is 110mbar, the diffusion temperat...

technical field

[0001] The present invention relates to the field of solar cell production diffusion. Background technique

[0002] With global warming, various renewable energy sources are developing rapidly. Among them, photovoltaics, as an important renewable energy source, have developed rapidly in the past fifteen years, and various types of batteries have blossomed. Among them, single-crystal high-efficiency PERC+SE batteries have initially achieved grid parity, making important contributions to the development of global new energy.

[0003] The core step in the production of solar cells is to prepare a PN junction, and the diffusion-prepared PN junction method is to use a heating method to incorporate V group impurities into P-type silicon or group III impurities into N-type silicon. The impurity element enters the silicon matrix due to thermal diffusion movement at high temperature, and its distribution in the matrix depends on the type of impurity element, initial ...

Examples

Embodiment 1

[0019] High temperature oxidation before diffusion: silicon wafer is oxidized at high temperature, and a layer of nanometer-thick SiO2 is pre-grown on the surface of the silicon wafer;

[0020] The process parameters are as follows: the pressure in the furnace is 110 mbar, the oxidation step time is maintained for 150 s, the flow rate of oxygen gas is 6000 sccm, the flow rate of nitrogen gas is 500 sccm to 2000 sccm, and the temperature is 750 ℃.

[0021] Low-pressure diffusion: The PN junction is prepared by a step-by-step diffusion method. The specific diffusion steps are as follows:

[0022] The first step of low-pressure diffusion, the process parameters are: the furnace pressure is 110 mbar, the diffusion temperature is 775 ℃; the diffusion time is 185 s; the nitrogen flow rate is 1200sccm; the phosphorus oxychloride flow rate is 900sccm; the oxygen flow rate is 700sccm;

[0023] Insulation buffer, the process conditions are: the pressure is 110mbar, the diffusion tempera...

Embodiment 2

[0030] High temperature oxidation before diffusion: silicon wafer is oxidized at high temperature, and a layer of nanometer-thick SiO2 is pre-grown on the surface of the silicon wafer;

[0031] The process parameters are as follows: the pressure in the furnace is 110 mbar, the oxidation step time is maintained for 150 s, the flow rate of oxygen gas is 6000 sccm, the flow rate of nitrogen gas is 500 sccm to 2000 sccm, and the temperature is 750 ℃.

[0032] Low-pressure diffusion: The PN junction is prepared by a step-by-step diffusion method. The specific diffusion steps are as follows:

[0033] The first step of low-pressure diffusion, the process parameters are: the furnace pressure is 110 mbar, the diffusion temperature is 775 ℃; the diffusion time is 185 s; the nitrogen flow rate is 1200sccm; the phosphorus oxychloride flow rate is 900sccm; the oxygen flow rate is 700sccm;

[0034] Insulation buffer, the process conditions are: the pressure is 110mbar, the diffusion tempera...

Embodiment 3

[0041] High temperature oxidation before diffusion: silicon wafer is oxidized at high temperature, and a layer of nanometer-thick SiO2 is pre-grown on the surface of the silicon wafer;

[0042]The process parameters are as follows: the pressure in the furnace is 110 mbar, the oxidation step time is maintained for 150 s, the flow rate of oxygen gas is 6000 sccm, the flow rate of nitrogen gas is 500 sccm to 2000 sccm, and the temperature is 750 ℃.

[0043] Low-pressure diffusion: The PN junction is prepared by a step-by-step diffusion method. The specific diffusion steps are as follows:

[0044] The first step of low-pressure diffusion, the process parameters are: the furnace pressure is 110 mbar, the diffusion temperature is 775 ℃; the diffusion time is 185 s; the nitrogen flow rate is 1200sccm; the phosphorus oxychloride flow rate is 900sccm; the oxygen flow rate is 700sccm;

[0045] Insulation buffer, the process conditions are: the pressure is 110mbar, the diffusion temperat...

Images