阅读说明：本技术 一种钝化接触电池及其制备方法和应用 (Passivated contact battery and preparation method and application thereof ) 是由 安欣睿 陈海燕 张临安 李兵 邓伟伟 于 2019-11-15 设计创作，主要内容包括：本发明提供了一种钝化接触电池及其制备方法和应用,所述钝化接触电池的制备方法包括氧化层的形成方法,所述氧化层的形成方法包括：先进行化学氧化,而后进行热氧化,形成所述氧化层；钝化接触的制备方法中氧化层采用化学氧化和热氧化叠加处理生长氧化层,便于快速均匀的形成氧化层；该钝化接触电池的制备方法得到的钝化接触电池具有较好的光转化效率和良率。(The invention provides a passivated contact battery and a preparation method and application thereof, wherein the preparation method of the passivated contact battery comprises a forming method of an oxidation layer, and the forming method of the oxidation layer comprises the following steps: carrying out chemical oxidation first, and then carrying out thermal oxidation to form the oxide layer; in the preparation method of the passivation contact, the oxide layer is subjected to superposition treatment of chemical oxidation and thermal oxidation to grow the oxide layer, so that the oxide layer can be quickly and uniformly formed; the passivated contact cell obtained by the preparation method of the passivated contact cell has better light conversion efficiency and yield.)

1. A method of making a passivated contact cell, the method comprising a method of forming an oxide layer, the method of forming the oxide layer comprising: and carrying out chemical oxidation first and then carrying out thermal oxidation to form the oxide layer.

2. The method of claim 1, wherein the chemical oxidation solvent comprises any one or a combination of at least two of an aqueous solution of hydrogen peroxide and concentrated sulfuric acid, an aqueous solution of hydrogen peroxide and ammonia water, or an aqueous solution of hydrogen peroxide and hydrochloric acid;

preferably, the chemical oxidation comprises: firstly, carrying out first-step chemical oxidation in an aqueous solution of hydrogen peroxide and concentrated sulfuric acid, secondly, carrying out second-step chemical oxidation in an aqueous solution of hydrogen peroxide and ammonia water, and thirdly, carrying out third-step chemical oxidation in an aqueous solution of hydrogen peroxide and hydrochloric acid;

preferably, the concentration of hydrogen peroxide in the aqueous solution of hydrogen peroxide and concentrated sulfuric acid is 1-10 wt%, and the concentration of concentrated sulfuric acid is 50-80 wt%;

preferably, the temperature of the first step of chemical oxidation is 70-110 ℃, and the time is 5-15 min;

preferably, the concentration of hydrogen peroxide in the aqueous solution of hydrogen peroxide and ammonia water is 1-10 wt%, and the concentration of ammonia water is 1-10 wt%;

preferably, the temperature of the second step of chemical oxidation is 60-80 ℃, and the time is 5-15 min;

preferably, the concentration of hydrogen peroxide in the aqueous solution of hydrogen peroxide and hydrochloric acid is 1-10 wt%, and the concentration of hydrochloric acid is 1-10 wt%;

preferably, the temperature of the third step of chemical oxidation is 60-80 ℃ and the time is 5-15 min.

3. A method of preparing a passivated contact cell according to claim 1 or 2 wherein the time of the thermal oxidation is 2-20 min;

preferably, the temperature of the thermal oxidation is 500-.

4. A method of manufacturing a passivated contact cell according to any of claims 1-3, characterized in that the method of manufacturing a passivated contact cell comprises the steps of:

(1) doping the front surface of the N-type substrate layer to obtain the N-type substrate layer with the front surface comprising the emitter layer;

(2) carrying out chemical oxidation on the back surface of the N-type substrate layer with the emitter layer on the front surface obtained in the step (1), then carrying out thermal oxidation to form an oxide layer to obtain an N-type substrate layer with the oxide layer on the back surface, and then forming a polycrystalline silicon doped layer on the back surface of the N-type substrate layer with the oxide layer on the back surface to obtain an N-type substrate layer with a silicon oxide layer and a polycrystalline silicon doped layer on the back surface;

(3) sequentially forming an oxidation passivation layer and an antireflection layer on the front side of the N-type substrate layer with the silicon oxide layer and the polycrystalline silicon doped layer on the back side obtained in the step (2), and forming a protection layer on the back side to obtain the N-type substrate layer with a passivation structure;

(4) and (4) respectively forming a front electrode layer and a back electrode layer on the front surface and the back surface of the N-type substrate layer with the passivation structure obtained in the step (3), and obtaining the passivated contact cell.

5. The method according to any one of claims 1 to 4, wherein the step (1) further comprises performing a texturing process before doping the front side of the N-type substrate layer;

preferably, the doping manner of step (1) includes boron diffusion;

preferably, the boron diffusion comprises flux deposition, drive-in treatment and oxidation treatment;

preferably, the temperature of the flux deposition is 850-950 ℃;

preferably, the time of the source deposition is 30-50 min;

preferably, the boron source for source deposition is boron tribromide;

preferably, the source deposition is carried out in boron tribromide with the flow rate of 100-;

preferably, the temperature of the propulsion treatment is 1000-;

preferably, the time of the propelling treatment is 40-80 min;

preferably, the propelling treatment is carried out in nitrogen at a flow rate of 10-20 slm;

preferably, the temperature of the oxidation treatment is 1000-1100 ℃;

preferably, the time of the oxidation treatment is 60-100 min;

preferably, the oxidation treatment is carried out under the condition of introducing oxygen with the flow rate of 10-20 slm;

preferably, the doping manner in the step (1) is boron diffusion, and an emitter layer and a borosilicate glass layer are sequentially laminated on the front surface, the back surface and the side surface of the N-type substrate layer after boron diffusion;

preferably, the doping manner in the step (1) is boron diffusion, and the step (1) further includes etching the boron-diffused N-type base layer to remove the emitter layer and the borosilicate glass layer which are sequentially stacked on the back surface and the side surface;

preferably, the etching treatment comprises an acid etching treatment and/or an alkali etching treatment, preferably an alkali etching treatment;

preferably, the solution for acid etching treatment is a hydrofluoric acid solution;

preferably, the concentration of the hydrofluoric acid solution is 2-10%;

preferably, the solution for alkali etching treatment is a sodium hydroxide solution and/or a potassium hydroxide solution;

preferably, the concentration of the solution for alkali etching treatment is 10-30%;

preferably, the depth of the etching treatment is 2-10 μm;

preferably, the sheet resistance of the emitter layer in the N-type base layer with the front surface comprising the emitter layer in the step (1) is 60-150 Ω.

6. The method according to any one of claims 1 to 5, wherein the doped layer of polycrystalline silicon of step (2) is formed by depositing polycrystalline silicon by low pressure chemical vapor deposition and then doping;

preferably, the pressure of the low pressure chemical vapor deposition process is 50 to 500 mTorr;

preferably, the doping mode is phosphorus diffusion;

preferably, the phosphorus diffusion comprises a first source deposition, a drive-in process and a second source deposition;

preferably, the temperature of the first-time source deposition is 700-;

preferably, the time of the first-time source deposition is 20-40 min;

preferably, the phosphorus source for the first-time source-through deposition is phosphorus oxychloride;

preferably, the first source deposition is carried out in the phosphorus oxychloride with the flow rate of 100-;

preferably, the temperature of the propulsion treatment is 800-;

preferably, the time of the propelling treatment is 30-50 min;

preferably, the propulsion treatment is carried out in the nitrogen with the flow rate of 500-;

preferably, the temperature of the second flux deposition is 700-;

preferably, the time of the second-time source deposition is 3-8 min;

preferably, the phosphorus source for the second-time source-through deposition is phosphorus oxychloride;

preferably, the second source deposition is carried out in the phosphorus oxychloride with the flow rate of 50-500sccm simultaneously;

preferably, the sheet resistance of the polycrystalline silicon doped layer in the step (2) is 20-200 Ω;

preferably, when the polycrystalline silicon doped layer is formed in the step (2), a phosphosilicate glass layer is further stacked on the surface of the polycrystalline silicon doped layer, and the front surface of the N-type substrate layer with the oxide layer on the back surface further comprises a phosphosilicate glass layer which is wound and plated with polycrystalline silicon and wound and expanded;

preferably, the step (2) further comprises performing post-treatment on the N-type substrate layer with the doped layer obtained after the polycrystalline silicon doped layer is formed;

preferably, the post-treatment comprises the steps of sequentially removing the phosphosilicate glass layer wound and expanded on the front surface of the N-type substrate layer with the doped layer, the polycrystalline silicon wound and plated, the borosilicate glass layer and the phosphosilicate glass layer on the back surface of the N-type substrate layer with the doped layer;

preferably, the post-processing mode comprises: firstly, removing the phosphosilicate glass layer wound and expanded on the front surface of the N-type substrate layer with the doped layer by using a first acid etching method, then removing the polycrystalline silicon wound and plated on the front surface of the N-type substrate layer with the doped layer by using an alkali etching method, and finally removing the borosilicate glass layer on the front surface of the N-type substrate layer with the doped layer and the phosphosilicate glass layer on the back surface of the N-type substrate layer with the doped layer by using a second acid etching method;

preferably, the solution for the first acid etching method is hydrofluoric acid;

preferably, the concentration of the solution for the first acid etching method is 2-10%;

preferably, the solution for the alkali etching method is a sodium hydroxide solution and/or a potassium hydroxide solution;

preferably, the concentration of the solution for the alkali etching method is 10-30%;

preferably, the solution for the second acid etching method is hydrofluoric acid;

preferably, the concentration of the solution for the second acid etching method is 5-20%.

7. The production method according to any one of claims 1 to 6, wherein the oxidation passivation layer of step (3) is formed by an atomic layer deposition method;

preferably, the anti-reflection layer in the step (3) is formed by an atomic layer deposition method or a plasma chemical vapor deposition method;

preferably, the protective layer in the step (3) is formed by plasma chemical vapor deposition;

preferably, the front electrode layer and the back electrode layer in step (4) are formed in a manner that an N-type substrate layer with a passivation structure is firstly subjected to screen printing and then sintered;

preferably, the width of the paste for screen printing is 20-50 μm, and the height is 10-25 μm;

preferably, the sintering temperature is 700-850 ℃;

preferably, the sintering time is 10-100 s.

8. The method of any one of claims 1-7, wherein the method of making a passivated contact cell comprises the steps of:

(1) the method comprises the following steps of (1) texturing an N-type substrate layer in advance, and then performing boron diffusion on the textured N-type substrate layer under the condition that a boron source is boron tribromide to obtain the N-type substrate layer with an emitter layer and a borosilicate glass layer sequentially laminated on the front surface, the back surface and the side surface;

(2) etching the N-type substrate layers which are obtained in the step (1) and are sequentially laminated with the emitter layer and the borosilicate glass layer on the front surface, the back surface and the side surface to remove the emitter layer and the borosilicate glass layer which are sequentially laminated on the back surface and the side surface, so as to obtain the N-type substrate layer of which the front surface comprises the emitter layer and the borosilicate glass layer, wherein the sheet resistance of the emitter layer is 60-150 omega;

(3) and (3) carrying out chemical oxidation on the back surface of the N-type substrate layer with the front surface comprising the emitter layer and the borosilicate glass layer, which is obtained in the step (2), in three steps sequentially: firstly, carrying out chemical oxidation in an aqueous solution of hydrogen peroxide and concentrated sulfuric acid (the concentration of the hydrogen peroxide is 1-10 wt%, and the concentration of the concentrated sulfuric acid is 50-80 wt%) at the temperature of 70-110 ℃ for 5-15 min; secondly, carrying out chemical oxidation in an aqueous solution of hydrogen peroxide and ammonia water (the concentration of the hydrogen peroxide is 1-10 wt%, and the concentration of the ammonia water is 1-10 wt%) at the temperature of 60-80 ℃ for 5-15 min; thirdly, carrying out chemical oxidation in aqueous solution of hydrogen peroxide and hydrochloric acid (the concentration of the hydrogen peroxide is 1-10 wt% and the concentration of the hydrochloric acid is 1-10 wt%) at the temperature of 60-80 ℃ for 5-15 min; secondly, carrying out thermal oxidation at the temperature of 500-; depositing polycrystalline silicon on the surface of the oxidation layer by a chemical vapor deposition method under the condition that the pressure is 50-500mTorr, and performing phosphorus diffusion under the condition that a phosphorus source is phosphorus oxychloride to obtain an N-type substrate layer with a doped layer;

(4) removing the phosphorosilicate glass layer on the front surface of the N-type substrate layer with the doped layer obtained in the step (3) through a first acid etching method, then removing the polycrystalline silicon wound and plated on the front surface of the N-type substrate layer with the doped layer through an alkali etching method, and finally removing the borosilicate glass layer on the front surface of the N-type substrate layer with the doped layer and the phosphorosilicate glass layer on the back surface through a second acid etching method to obtain the N-type substrate layer with the silicon oxide layer and the polycrystalline silicon doped layer on the back surface, wherein the square resistance of the polycrystalline silicon doped layer is 20-200 omega;

(5) forming an oxidation passivation layer on the front side of the processed N-type substrate layer with the silicon oxide layer and the N-type polycrystalline silicon layer on the back side obtained in the step (4) by an atomic layer deposition method, forming an antireflection layer by an atomic layer deposition method or a plasma chemical vapor deposition method, and forming a protection layer on the back side by a plasma chemical vapor deposition method to obtain the N-type substrate layer with a passivation structure;

(6) and (4) firstly carrying out screen printing on the N-type substrate layer with the passivation structure obtained in the step (5), and then sintering at the temperature of 700-850 ℃ for 10-100s to form a front electrode layer and a back electrode layer so as to obtain the passivation contact battery.

9. A passivated contact cell, wherein the passivated contact cell is obtained by the method of making a passivated contact cell according to any of claims 1-8.

10. Use of a passivated contact cell according to claim 9 as an energy cell in a solar ac power plant.

Technical Field

The invention belongs to the field of solar cells, relates to a passivated contact cell and a preparation method and application thereof, and particularly relates to a preparation method of the passivated contact cell, the passivated contact cell prepared by the preparation method, and the application of the passivated contact cell.

Background

In recent years, with the development of single crystal solar cells, especially the successful industrialization of passivated emitter and back field (PERC) technology, the efficiency improvement of mass production of cell efficiency on P-type silicon wafers approaches the bottleneck. More sunlight is projected to the N-type battery with longer minority carrier lifetime and smaller attenuation. The three cell structures of N-type PERT, Heterojunction (HJT), and tunnel oxide passivation contact (TOPCon) are also receiving increasing attention. The TOPCon structure utilizes an ultrathin oxide layer and doped polysilicon to form passivation contact, provides good passivation effect on the surface and contact parts, and has low contact resistance. Therefore, compared with the PERX structure, the TOPCon structure can bring advantages in terms of Fill Factor (FF) on the premise of ensuring open-circuit voltage (Voc) by reducing metal contact area to reduce contact recombination loss. Meanwhile, the passivation effect of the ultrathin oxide layer and the doped polysilicon is superior to that of common passivation films such as SiNx, and the Voc of the TOPCon battery can reach more than 700mV in mass production. Compared to HJT cells, TOPCon cells compensate for short circuit current (Isc) and FF, although Voc is lower, and ultimately the efficiency is not much different. More importantly, the mass production of TOPCon batteries only needs to simply transform the existing PERC or N-PERT production line, and a polysilicon deposition device is added (boron doping devices are added to the PERC production line), while the whole production line needs to be replaced by HJT, and huge early-stage investment is needed. Also, the requirement for HJT is more stringent in cleanliness than TOPCon.

CN206340553U discloses an N-type double-sided solar cell, which includes a silicon nitride layer, an aluminum oxide layer, a boron diffusion layer, an N-type silicon substrate, a phosphorus diffusion layer, and a silicon nitride passivation antireflection film, which are stacked in sequence, wherein the silicon nitride layer and the aluminum oxide layer form a stacked aluminum oxide/silicon nitride passivation layer, an etching groove corresponding to each secondary gate line electrode is formed on the aluminum oxide/silicon nitride passivation layer by etching, and the secondary gate line electrode is filled in the etching groove to form ohmic contact, but the cell efficiency still needs to be improved.

CN105244412A discloses a passivation method of a boron emitter of an N-type crystalline silicon battery, which comprises the following passivation steps: firstly, respectively forming a phosphorus-doped N + layer and a boron emitter P + layer on two sides of an N-type silicon substrate; then carrying out oxidation passivation treatment on the N-type silicon substrate, and respectively generating silicon oxide films on the phosphorus-doped N + layer and the boron emitter P + layer; finally, depositing SiNx thin films on the silicon oxide thin films on the two sides of the N-type silicon substrate; the preparation process is simple, the controllability of the manufacturing process is strong, the equipment cost is low, the material consumption cost is low, the preparation method can be compatible with the equipment of the current crystalline silicon cell manufacturing production line, and the preparation method is suitable for large-scale industrial production, but the solar energy efficiency of the preparation method still needs to be improved.

Therefore, there is a need for a passivated contact cell with high light conversion efficiency and simple fabrication process.

Disclosure of Invention

The invention aims to provide a passivated contact battery and a preparation method and application thereof, wherein an oxide layer is formed by superposition of chemical oxidation and thermal oxidation treatment, so that the oxide layer is conveniently and uniformly formed, and a certain cleaning effect is achieved; the passivated contact cell prepared by the preparation method of the passivated contact cell has better light conversion efficiency and yield.

In order to achieve the purpose, the invention adopts the following technical scheme:

one of the objects of the present invention is to provide a method for manufacturing a passivated contact cell, said method comprising a method for forming an oxide layer, said method for forming an oxide layer comprising: and carrying out chemical oxidation first and then carrying out thermal oxidation to form the oxide layer.

In the present invention, the solvent for chemical oxidation includes any one of or a combination of at least two of an aqueous solution of hydrogen peroxide and concentrated sulfuric acid, an aqueous solution of hydrogen peroxide and aqueous ammonia, or an aqueous solution of hydrogen peroxide and hydrochloric acid.

In the present invention, the chemical oxidation includes: the first step of chemical oxidation is carried out in the aqueous solution of hydrogen peroxide and concentrated sulfuric acid, the second step of chemical oxidation is carried out in the aqueous solution of hydrogen peroxide and ammonia water, and the third step of chemical oxidation is carried out in the aqueous solution of hydrogen peroxide and hydrochloric acid.

In the present invention, the concentration of hydrogen peroxide in the aqueous solution of hydrogen peroxide and concentrated sulfuric acid is 1 to 10 wt% (e.g., 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, etc.), and the concentration of concentrated sulfuric acid is 50 to 80 wt% (e.g., 50 wt%, 52 wt%, 55 wt%, 57 wt%, 60 wt%, 62 wt%, 65 wt%, 67 wt%, 70 wt%, 72 wt%, 75 wt%, 77 wt%, 80 wt%, etc.). When the concentration of hydrogen peroxide and/or concentrated sulfuric acid in the aqueous solution of hydrogen peroxide and concentrated sulfuric acid is not within the range, the formed oxide layer may be thicker or thinner.

In the present invention, the temperature of the first step chemical oxidation is 70-110 ℃ (e.g. 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, etc.), and the time is 5-15min (e.g. 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min, 15min, etc.).

In the present invention, the concentration of hydrogen peroxide in the aqueous solution of hydrogen peroxide and aqueous ammonia is 1 to 10 wt.% (e.g., 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc.), and the concentration of aqueous ammonia is 1 to 10 wt.% (e.g., 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc.). When the concentration of hydrogen peroxide and/or ammonia in the aqueous solution of hydrogen peroxide and ammonia is not within this range, the oxide layer formed may be thicker or thinner, or the substrate surface may be etched.

In the present invention, the temperature of the second step chemical oxidation is 60-80 ℃ (e.g. 60 ℃, 62 ℃, 65 ℃, 67 ℃, 70 ℃, 72 ℃, 75 ℃, 77 ℃, 80 ℃ etc.), and the time is 5-15min (e.g. 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min, 15min, etc.).

In the present invention, the concentration of hydrogen peroxide in the aqueous solution of hydrogen peroxide and hydrochloric acid is 1 to 10 wt.% (e.g., 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc.), and the concentration of hydrochloric acid is 1 to 10 wt.% (e.g., 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc.). When the concentration of hydrogen peroxide and/or hydrochloric acid in the aqueous solution of hydrogen peroxide and ammonia water is out of this range, the oxide layer formed is thicker or thinner.

In the present invention, the temperature of the third step of chemical oxidation is 60-80 ℃ (e.g., 60 ℃, 62 ℃, 65 ℃, 67 ℃, 70 ℃, 72 ℃, 75 ℃, 77 ℃, 80 ℃, etc.), and the time is 5-15min (e.g., 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min, 15min, etc.).

In the present invention, the time of the thermal oxidation is 2-20min, such as 2min, 5min, 7min, 10min, 12min, 15min, 17min, 20min, etc.

In the present invention, the thermal oxidation temperature is 500-600 deg.C, such as 500 deg.C, 510 deg.C, 520 deg.C, 530 deg.C, 540 deg.C, 550 deg.C, 560 deg.C, 570 deg.C, 580 deg.C, 590 deg.C, 600 deg.C, etc.

In the present invention, the method of making the passivated contact cell comprises the steps of:

(1) doping the front surface of the N-type substrate layer to obtain the N-type substrate layer with the front surface comprising the emitter layer;

(2) carrying out chemical oxidation on the back surface of the N-type substrate layer with the emitter layer on the front surface obtained in the step (1), then carrying out thermal oxidation to form an oxide layer to obtain an N-type substrate layer with the oxide layer on the back surface, and then forming a polycrystalline silicon doped layer on the back surface of the N-type substrate layer with the oxide layer on the back surface to obtain an N-type substrate layer with a silicon oxide layer and a polycrystalline silicon doped layer on the back surface;

(3) sequentially forming an oxidation passivation layer and an antireflection layer on the front side of the N-type substrate layer with the silicon oxide layer and the polycrystalline silicon doped layer on the back side obtained in the step (2), and forming a protection layer on the back side to obtain the N-type substrate layer with a passivation structure;

(4) and (4) respectively forming a front electrode layer and a back electrode layer on the front surface and the back surface of the N-type substrate layer with the passivation structure obtained in the step (3), and obtaining the passivated contact cell.

The preparation method of the passivated contact electrode is simple, easy to realize and has a relatively high industrial application prospect.

In the present invention, the N-type substrate refers to silicon doped with an element of main group V, and illustratively includes a phosphorus-doped single crystal silicon wafer or a phosphorus-doped pseudo single crystal silicon wafer; the N-type base layer will be referred to hereinafter in the same sense.

In the present invention, the step (1) further includes performing a texturing process before doping the front side of the N-type substrate layer.

In the invention, the pyramid structure is formed by texturing the surface of the N-type silicon wafer layer, so that incident light can be reflected and refracted on the silicon surface for multiple times, and the short-circuit voltage and the conversion efficiency of the cell are improved.

In the invention, the doping manner in the step (1) comprises boron diffusion.

In the present invention, the boron diffusion includes a flux deposition, a drive-in process, and an oxidation process.

In the present invention, the temperature of the flux deposition is 850-.

In the present invention, the deposition time of the flux source is 30-50min, such as 30min, 32min, 35min, 37min, 40min, 42min, 45min, 47min, 50min, etc.

In the invention, the boron source for the through-source deposition is boron tribromide.

In the present invention, the source deposition is performed in boron tribromide at a flow rate of 100-1000sccm (e.g., 100sccm, 200sccm, 300sccm, 400sccm, 500sccm, 600sccm, 700sccm, 800sccm, 900sccm, 1000sccm, etc.).

In the present invention, the temperature of the boosting treatment is 1000-.

In the present invention, the time of the propelling treatment is 40-80min, such as 40min, 45min, 50min, 55min, 60min, 65min, 70min, 75min, 80min, etc.

In the present invention, the propulsion process is performed in nitrogen gas at a flow rate of 10 to 20slm (e.g., 10slm, 11slm, 12slm, 13slm, 14slm, 15slm, 16slm, 17slm, 18slm, 19slm, 20slm, etc.).

In the present invention, the temperature of the oxidation treatment is 1000-.

In the present invention, the time of the oxidation treatment is 60-100min, such as 60min, 65min, 70min, 75min, 80min, 85min, 90min, 95min, 100min, etc.

In the present invention, the oxidation treatment is performed under the condition that oxygen gas is introduced at a flow rate of 10 to 20slm (for example, 10slm, 11slm, 12slm, 13slm, 14slm, 15slm, 16slm, 17slm, 18slm, 19slm, 20slm, etc.).

In the invention, the doping mode in the step (1) is boron diffusion, and an emitter layer and a borosilicate glass layer are sequentially laminated on the front surface, the back surface and the side surface of the N-type substrate layer after boron diffusion.

In the present invention, the lamination refers to a positional state of the end office, and does not represent a forming process.

In the invention, the doping manner in the step (1) is boron diffusion, and the step (1) further comprises the step of etching the boron-diffused N-type base layer to remove the emitter layer and the borosilicate glass layer which are sequentially laminated on the back surface and the side surface.

According to the invention, the emitter layer and the borosilicate glass layer are formed on the front surface of the N-type substrate layer in a boron diffusion mode, so that phosphorus can be effectively prevented from diffusing into the front emitter layer when a polycrystalline silicon doping layer is subsequently carried out, masking treatment is not required, the process cost and time are greatly saved, and the borosilicate glass layer can be simultaneously removed when the phosphorus silicate glass layer and the wound and plated polycrystalline silicon are subsequently removed, so that the use of a final passivated contact battery is not influenced.

In the present invention, the etching treatment includes an acid etching treatment and/or an alkali etching treatment, preferably an alkali etching treatment.

In the invention, the solution for acid etching treatment is hydrofluoric acid.

In the present invention, the concentration of the solution for acid etching treatment is 2 to 10%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

In the invention, the solution for alkali etching treatment is a sodium hydroxide solution and/or a potassium hydroxide solution.

In the present invention, the concentration of the alkali etching solution is 10 to 30%, for example, 10%, 12%, 15%, 17%, 20%, 22%, 25%, 27%, 30%, etc.

In the present invention, the depth of the etching treatment is 2 to 10 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

In the present invention, the sheet resistance of the emitter layer in the N-type base layer whose front side includes the emitter layer in step (1) is 60 to 150 Ω, for example, 60 Ω, 70 Ω, 80 Ω, 90 Ω, 100 Ω, 110 Ω, 120 Ω, 130 Ω, 140 Ω, 150 Ω, and the like. In the invention, the polysilicon doping layer in the step (2) is formed by depositing polysilicon by a low pressure chemical vapor deposition method and then doping.

In the present invention, the low pressure chemical vapor deposition process is at a pressure of 50 to 500mTorr, such as 50mTorr, 100mTorr, 120mTorr, 150mTorr, 180mTorr, 200mTorr, 220mTorr, 250mTorr, 270mTorr, 300mTorr, 350mTorr, 400mTorr, 450mTorr, 500mTorr, and the like.

In the invention, the doping mode is phosphorus diffusion.

In the invention, the phosphorus diffusion comprises a first source deposition, a drive-in process and a second source deposition.

In the present invention, the temperature of the first pass deposition is 700-.

In the present invention, the time of the first-time source deposition is 20-40min, such as 20min, 22min, 25min, 27min, 30min, 32min, 35min, 37min, 40min, etc.

In the invention, the phosphorus source for the first-time source-through deposition is phosphorus oxychloride.

In the present invention, the first source deposition is performed in introducing phosphorus oxychloride with a flow rate of 100sccm and 1000sccm (e.g., 100sccm, 200sccm, 300sccm, 400sccm, 500sccm, 600sccm, 700sccm, 800sccm, 900sccm, 1000sccm, etc.);

in the present invention, the temperature of the boosting treatment is 800-.

In the present invention, the time of the advancing treatment is 30-50min, such as 30min, 32min, 35min, 37min, 40min, 42min, 45min, 47min, 50min, etc.

In the present invention, the propulsion process is performed in nitrogen gas with a flow rate of 500-5000sccm (e.g., 500sccm, 1000sccm, 1500sccm, 2000sccm, 2500sccm, 3000sccm, 3500sccm, 4000sccm, 4500sccm, 5000sccm, etc.);

in the present invention, the temperature of the second pass deposition is 700-.

In the present invention, the time of the second flux deposition is 3-8min, such as 3min, 4min, 5min, 6min, 7min, 8min, etc.

In the invention, the phosphorus source for the second-time source-through deposition is phosphorus oxychloride.

In the present invention, the second source deposition is performed by introducing phosphorus oxychloride with a flow rate of 50-500sccm (e.g., 50sccm, 100sccm, 150sccm, 200sccm, 250sccm, 300sccm, 350sccm, 400sccm, 450sccm, 500sccm, etc.).

In the invention, the sheet resistance of the polysilicon doped layer in the step (2) is 20-200 Ω, such as 20 Ω, 50 Ω, 70 Ω, 100 Ω, 120 Ω, 150 Ω, 170 Ω, 200 Ω, and the like.

In the invention, when the polycrystalline silicon doped layer is formed in the step (2), a phosphorosilicate glass layer is further laminated on the surface of the polycrystalline silicon doped layer, and the front surface of the N-type substrate layer with the oxide layer on the back surface further comprises a phosphorosilicate glass layer which is wound and plated with polycrystalline silicon and wound and expanded.

In the invention, the step (2) further comprises performing post-treatment on the N-type substrate layer with the doped layer obtained after the polycrystalline silicon doped layer is formed.

In the invention, the post-treatment comprises the steps of sequentially removing the phosphosilicate glass layer wound and expanded on the front surface of the N-type substrate layer with the doped layer, the polycrystalline silicon wound and plated, the borosilicate glass layer and the phosphosilicate glass layer on the back surface of the N-type substrate layer with the doped layer.

In the present invention, the post-processing method includes: firstly removing the phosphosilicate glass layer wound and expanded on the front surface of the N-type substrate layer with the doped layer by using a first acid etching method, then removing the polycrystalline silicon wound and plated on the front surface of the N-type substrate layer with the doped layer by using an alkali etching method, and finally removing the borosilicate glass layer on the front surface of the N-type substrate layer with the doped layer and the phosphosilicate glass layer on the back surface of the N-type substrate layer with the doped layer by using a second acid etching method.

In the invention, the solution for the first acid etching method is hydrofluoric acid.

In the present invention, the concentration of the first acid etching solution is 2 to 10%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

In the invention, the solution for the alkali etching method is a sodium hydroxide solution and/or a potassium hydroxide solution.

In the present invention, the concentration of the solution for alkali etching is 10 to 30%, for example, 10%, 12%, 15%, 17%, 20%, 22%, 25%, 27%, 30%, etc.

In the invention, the solution for the second acid etching method is hydrofluoric acid.

In the present invention, the concentration of the solution for the second acid etching method is 5 to 20%, for example, 5%, 7%, 10%, 12%, 15%, 17%, 20%, etc.

In the invention, the oxidation passivation layer in the step (3) is formed by an atomic layer deposition method.

In the invention, the anti-reflection layer in the step (3) is formed by an atomic layer deposition method or a plasma chemical vapor deposition method.

In the invention, the protective layer in the step (3) is formed by plasma chemical vapor deposition.

In the invention, the front electrode layer and the back electrode layer in the step (4) are formed in a manner that the N-type substrate layer with the passivation structure is firstly subjected to screen printing and then sintered.

According to the invention, the front electrode layer and the back electrode layer are formed by adopting screen printing and sintering modes, and grooving treatment is not required, because the electrode material is silver paste or silver-aluminum paste, the protective layer, the oxidation passivation layer and the anti-reflection layer can be burnt through, so that the electrode material is connected with the emitter layer and the polycrystalline silicon doped layer.

In the present invention, the paste for screen printing has a width of 20 to 50 μm (e.g., 20 μm, 22 μm, 25 μm, 27 μm, 30 μm, 32 μm, 35 μm, 37 μm, 40 μm, 42 μm, 45 μm, 47 μm, 50 μm, etc.) and a height of 10 to 25 μm (e.g., 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, etc.).

In the present invention, the sintering temperature is 700-850 deg.C, such as 700 deg.C, 720 deg.C, 750 deg.C, 770 deg.C, 800 deg.C, 820 deg.C, 850 deg.C, etc.

In the present invention, the sintering time is 10 to 100s, for example, 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, etc.

As a preferred technical scheme of the invention, the preparation method comprises the following steps:

(1) the method comprises the following steps of (1) texturing an N-type substrate layer in advance, and then performing boron diffusion on the textured N-type substrate layer under the condition that a boron source is boron tribromide to obtain the N-type substrate layer with an emitter layer and a borosilicate glass layer sequentially laminated on the front surface, the back surface and the side surface;

(2) etching the N-type substrate layers which are obtained in the step (1) and are sequentially laminated with the emitter layer and the borosilicate glass layer on the front surface, the back surface and the side surface to remove the emitter layer and the borosilicate glass layer which are sequentially laminated on the back surface and the side surface, so as to obtain the N-type substrate layer of which the front surface comprises the emitter layer and the borosilicate glass layer, wherein the sheet resistance of the emitter layer is 60-150 omega;

(3) and (3) carrying out chemical oxidation on the back surface of the N-type substrate layer with the front surface comprising the emitter layer and the borosilicate glass layer, which is obtained in the step (2), in three steps sequentially: firstly, carrying out chemical oxidation in an aqueous solution of hydrogen peroxide and concentrated sulfuric acid (the concentration of the hydrogen peroxide is 1-10 wt%, and the concentration of the concentrated sulfuric acid is 50-80 wt%) at the temperature of 70-110 ℃ for 5-15 min; secondly, carrying out chemical oxidation in an aqueous solution of hydrogen peroxide and ammonia water (the concentration of the hydrogen peroxide is 1-10 wt%, and the concentration of the ammonia water is 1-10 wt%) at the temperature of 60-80 ℃ for 5-15 min; thirdly, carrying out chemical oxidation in aqueous solution of hydrogen peroxide and hydrochloric acid (the concentration of the hydrogen peroxide is 1-10 wt% and the concentration of the hydrochloric acid is 1-10 wt%) at the temperature of 60-80 ℃ for 5-15 min; secondly, carrying out thermal oxidation at the temperature of 500-600 ℃ for 2-20min to grow and form an oxide layer to obtain an N-type substrate layer with the oxide layer on the back surface, then depositing polycrystalline silicon on the surface of the oxide layer by a chemical vapor deposition method under the condition that the pressure is 50-500mTorr, and carrying out phosphorus diffusion under the condition that a phosphorus source is phosphorus oxychloride to obtain the N-type substrate layer with the doped layer;

(4) removing the phosphorosilicate glass layer on the front surface of the N-type substrate layer with the doped layer obtained in the step (3) through a first acid etching method, then removing the polycrystalline silicon wound and plated on the front surface of the N-type substrate layer with the doped layer through an alkali etching method, and finally removing the borosilicate glass layer on the front surface of the N-type substrate layer with the doped layer and the phosphorosilicate glass layer on the back surface through a second acid etching method to obtain the N-type substrate layer with the silicon oxide layer and the polycrystalline silicon doped layer on the back surface, wherein the square resistance of the polycrystalline silicon doped layer is 20-200 omega;

(5) forming an oxidation passivation layer on the front side of the processed N-type substrate layer with the silicon oxide layer and the N-type polycrystalline silicon layer on the back side obtained in the step (4) by an atomic layer deposition method, forming an antireflection layer by an atomic layer deposition method or a plasma chemical vapor deposition method, and forming a protection layer on the back side by a plasma chemical vapor deposition method to obtain the N-type substrate layer with a passivation structure;

(6) and (4) firstly carrying out screen printing on the N-type substrate layer with the passivation structure obtained in the step (5), and then sintering at the temperature of 700-850 ℃ for 10-100s to form a front electrode layer and a back electrode layer so as to obtain the passivation contact battery.

It is a fourth object of the present invention to provide a passivated contact cell prepared by the method of the third object.

The passivated contact cell comprises:

an N-type base layer;

the emitter layer, the oxidation passivation layer, the anti-reflection layer and the front electrode layer are sequentially arranged on the front surface of the N-type substrate layer, and the front electrode layer sequentially penetrates through the anti-reflection layer and the oxidation passivation layer and is connected with the emitter layer;

and the oxide layer, the polycrystalline silicon doping layer, the protection layer and the back electrode layer are sequentially arranged on the back surface of the N-type substrate layer, and the back electrode layer penetrates through the protection layer and is connected with the polycrystalline silicon doping layer.

The passivated contact cell of the invention has the advantages of long bulk minority carrier lifetime, low attenuation and high light conversion efficiency; the oxidation layer and the polycrystalline silicon doping layer are arranged on the reverse side of the N-type substrate layer, and passivation contact is formed between the oxidation layer and the polycrystalline silicon doping layer and the protection layer, so that the low contact resistance is realized under the effect of ensuring good surface contact, and the advantage of filling factors can be kept on the premise of ensuring open-circuit voltage. In addition, the cell structure is also suitable for single-sided and double-sided photovoltaic modules.

In the present invention, it is to be understood that the terms "front" and "back" indicate orientations and positional relationships based on those shown in the drawings, which are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the invention, it is to be noted that, unless explicitly stated or limited otherwise, the terms "connected" and "connected" are to be interpreted broadly, e.g. as a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

In the present invention, the thickness of the N-type underlayer is 180 μm, such as 180 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 150 μm, 155 μm, 160 μm, 165 μm, 170 μm, 175 μm, 180 μm, etc.

In the present invention, the emitter layer is a P + emitter layer.

In the present invention, the thickness of the emitter layer is 0.2 to 2 μm, for example, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2 μm, etc. When the thickness of the emitter layer is higher than 2 μm, the collection efficiency of electron-hole pairs is low, and the short-circuit current of the battery is reduced; when the thickness of the emitter layer is less than 0.2 μm, there is a risk that the front metal electrode penetrates through the PN junction, resulting in a decrease in fill factor.

In the present invention, the oxidation passivation layer is an aluminum oxide passivation layer.

In the present invention, the thickness of the oxidation passivation layer is 2-20nm, such as 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm, 20nm, etc. When the thickness of the oxidation passivation layer is higher than 20nm, the contact of the back electrode is influenced; when the thickness of the oxidation passivation layer is less than 2nm, there is a risk of poor thermal stability and affecting the passivation effect.

In the invention, the anti-reflection layer is a silicon nitride anti-reflection layer.

In the present invention, the thickness of the antireflective layer is 50 to 200nm, for example, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, etc.

In the present invention, the antireflection layer has a refractive index of 1.9 to 2.2%, for example, 1.9%, 2.0%, 2.1%, 2.2%, etc. If the refractive index of the antireflective layer is too high or too low, the short circuit current of the passivated contact cell will be affected, thereby affecting the light conversion efficiency of the passivated contact cell.

In the present invention, the front electrode layer is a metal electrode layer.

In the invention, the front electrode layer is a silver-aluminum alloy electrode layer.

In the present invention, the thickness of the front electrode layer is 10 to 30 μm, for example, 10 μm, 12 μm, 15 μm, 17 μm, 20 μm, 22 μm, 25 μm, 27 μm, 30 μm, and the like.

In the present invention, the oxide layer is a silicon oxide layer.

In the present invention, the thickness of the oxide layer is 1 to 3nm, for example, 1nm, 1.2nm, 1.5nm, 1.7nm, 2nm, 2.2nm, 2.5nm, 2.7nm, 3nm, etc. When the thickness of the oxide layer is higher than 3nm, good contact with the back electrode cannot be formed; when the thickness of the oxide layer is less than 1nm, the passivation effect is affected.

In the present invention, the thickness of the doped layer of polysilicon is 50-300nm, such as 50nm, 70nm, 100nm, 120nm, 150nm, 170nm, 200nm, 220nm, 250nm, 270nm, 300nm, etc. When the thickness of the polycrystalline silicon doped layer is higher than 300nm, the parasitic absorption of the layer to a long-wave spectrum can cause the long-wave response of the battery to be too low; when the thickness of the doped layer of polysilicon is less than 50nm, the sintering of the back electrode is affected.

In the present invention, the protective layer is a silicon nitride layer.

In the present invention, the thickness of the protective layer is 50 to 200nm, for example, 50nm, 70nm, 100nm, 120nm, 150nm, 170nm, 200 nm.

In the present invention, the back electrode layer is a metal electrode layer.

In the present invention, the back electrode layer is a silver electrode layer.

In the present invention, the back electrode layer has a thickness of 5 to 20 μm, for example, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, or the like.

The invention also provides the use of the passivated contact cell according to one of the above objects as an energy cell in a solar ac power generation device.

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

in the preparation method of the passivation contact, the oxide layer is subjected to superposition treatment of chemical oxidation and thermal oxidation to grow the oxide layer, so that the oxide layer is conveniently and uniformly formed, and a certain cleaning effect is achieved; the passivated contact cell obtained by the preparation method of the passivated contact cell has better light conversion efficiency and yield, and the light conversion efficiency is as high as 23.27%.

Drawings

FIG. 1 is a schematic diagram of the structure of a passivated contact cell in example 1 of the invention;

the substrate comprises an N-type substrate layer 1, an emitter layer 2, an oxidation passivation layer 3, an antireflection layer 4, a front electrode layer 5, an oxidation layer 6, a polycrystalline silicon doping layer 7, a protection layer 8 and a back electrode layer 9.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

The embodiment provides a preparation method of a passivated contact electrode, which comprises the following steps:

(1) carrying out texture etching on an N-type substrate layer (a phosphorus-doped monocrystalline silicon wafer) in advance, then carrying out boron diffusion on the textured N-type substrate layer in three steps, wherein in the first step, in boron tribromide with the flow rate of 500sccm, source deposition is carried out at the temperature of 900 ℃ for 40min, in the second step, in nitrogen with the flow rate of 15slm, propulsion treatment is carried out at the temperature of 1050 ℃ for 60min, in the third step, in oxygen with the flow rate of 15slm, oxidation treatment is carried out at the temperature of 1050 ℃ for 80min, and the N-type substrate layer with an emitter layer and a borosilicate glass layer sequentially laminated on the front surface, the back surface and the side surface is obtained;

(2) performing hydrofluoric acid etching treatment with the concentration of 8% on the N-type substrate layers with the front surface, the back surface and the side surfaces obtained in the step (1) and sequentially laminating the emitter layer and the borosilicate glass layer to remove the emitter layer and the borosilicate glass layer with the back surface and the side surfaces sequentially laminated to obtain the N-type substrate layer with the front surface comprising the emitter layer and the borosilicate glass layer, wherein the sheet resistance of the emitter layer is 100 omega;

(3) and (3) carrying out the following chemical oxidation on the back surface of the N-type substrate layer with the front surface comprising the emitter layer and the borosilicate glass layer obtained in the step (2) in sequence: a. performing first-step chemical oxidation in an aqueous solution of concentrated sulfuric acid and hydrogen peroxide (wherein the concentration of the hydrogen peroxide is 5 wt%, and the concentration of the concentrated sulfuric acid is 60 wt%) at 90 ℃ for 10 min; b. performing second-step chemical oxidation in aqueous solution of hydrogen peroxide and ammonia water (wherein, the concentration of hydrogen peroxide is 5 wt%, and the concentration of ammonia water is 5 wt%) at 70 deg.C for 10 min; c. carrying out a third step of chemical oxidation in an aqueous solution of hydrogen peroxide and hydrochloric acid (the concentration of hydrogen peroxide is 5 wt%, and the concentration of hydrochloric acid is 5 wt%) at 70 ℃ for 10 min; performing thermal oxidation at 580 ℃ for 10min, growing to obtain an N-type substrate layer with an oxide layer on the back surface, depositing polycrystalline silicon on the surface of the oxide layer by a chemical vapor deposition method under the condition that the pressure is 300mTorr, performing phosphorus diffusion in three steps under the condition that a phosphorus source is phosphorus oxychloride, performing first source-through deposition at 750 ℃ for 30min in phosphorus oxychloride with the flow rate of 500sccm, performing propulsion treatment at 900 ℃ for 40min in nitrogen with the flow rate of 3000sccm at the same time in the second step, performing second source-through deposition at 770 ℃ for 5min in phosphorus oxychloride with the flow rate of 300sccm at the same time in the third step, and obtaining the N-type substrate layer with the doped layer;

(4) removing the phosphosilicate glass layer on the front surface of the N-type substrate layer with the doped layer obtained in the step (3) by using a hydrofluoric acid solution etching method with the concentration of 5% for the first time, then removing the polycrystalline silicon wound and plated on the front surface of the N-type substrate layer with the doped layer by using a potassium hydroxide solution etching method with the concentration of 20%, and finally removing the borosilicate glass layer on the front surface of the N-type substrate layer with the doped layer and the phosphosilicate glass layer on the back surface by using a hydrofluoric acid etching method with the concentration of 10% for the second time to obtain the N-type substrate layer with the silicon oxide layer and the polycrystalline silicon doped layer on the back surface, wherein the sheet resistance of the polycrystalline silicon doped layer is 100 omega;

(5) forming an aluminum oxide passivation layer with the thickness of 5nm on the front side of the processed N-type substrate layer with the silicon oxide layer and the N-type polycrystalline silicon layer on the back side obtained in the step (4) by an atomic layer deposition method, then forming a silicon nitride antireflection layer with the thickness of 80nm and the refractive index of 2.02 by a plasma chemical vapor deposition method, and forming a silicon nitride protection layer with the thickness of 120nm on the back side by the plasma chemical vapor deposition method to obtain the N-type substrate layer with a passivation structure;

(6) and (4) firstly carrying out screen printing on the N-type substrate layer with the passivation structure obtained in the step (5), and then sintering at 800 ℃ for 60s to form a front Ag-Al electrode layer and a back Ag electrode layer, thus obtaining the passivation contact battery.

The passivated contact cell obtained by the above-described preparation method, as shown in fig. 1, comprises:

an N-type substrate layer 1;

the light-emitting diode comprises an emitter layer 2, an oxidation passivation layer 3, an anti-reflection layer 4 and a front electrode layer 5 which are arranged on the front surface of an N-type substrate layer 1 and are sequentially connected, wherein the front electrode layer 5 sequentially penetrates through the anti-reflection layer 4 and the oxidation passivation layer 3 and is connected with the emitter layer 2;

the back electrode layer 9 penetrates through the protection layer 8 and is connected with the polycrystalline silicon doped layer 7;

wherein the thickness of the N-type substrate layer is 150 μm; the emitter layer is a P + emitter layer; the thickness of the P + emitter layer is 1 μm; the oxidation passivation layer is an aluminum oxide passivation layer; the thickness of the aluminum oxide passivation layer is 10 nm; the anti-reflection layer is a silicon nitride anti-reflection layer; the thickness of the antireflection layer is 100 nm; the refractive index of the anti-reflection layer is 2.02; the front electrode layer is an Ag-Al electrode layer; the thickness of the front electrode layer is 20 μm; the oxide layer is a silicon oxide layer; the thickness of the silicon oxide layer is 2 nm; the thickness of the polycrystalline silicon doping layer is 200 nm; the protective layer is a silicon nitride layer; the thickness of the silicon nitride layer is 100 nm; the back electrode layer is a silver electrode layer; the thickness of the silver electrode layer was 10 μm.

Example 2

The embodiment provides a preparation method of a passivated contact electrode, which comprises the following steps:

(1) carrying out texture etching on an N-type substrate layer (a phosphorus-doped monocrystalline silicon wafer) in advance, then carrying out boron diffusion on the textured N-type substrate layer in three steps, wherein in the first step, in boron tribromide with the flow of 100sccm, source deposition is carried out at the temperature of 850 ℃ for 50min, in the second step, in nitrogen with the flow of 20slm, propulsion treatment is carried out at the temperature of 1000 ℃ for 100min, in the third step, in the same time, oxygen with the flow of 20slm is introduced, and oxidation treatment is carried out at the temperature of 1100 ℃ for 60min, so that the N-type substrate layer with an emitter layer and a borosilicate glass layer sequentially laminated on the front surface, the back surface and the side surface is obtained;

(2) carrying out hydrofluoric acid etching treatment with the concentration of 2% on the N-type substrate layers with the emitter layer and the borosilicate glass layer sequentially laminated on the front surface, the back surface and the side surface obtained in the step (1) to remove the emitter layer and the borosilicate glass layer sequentially laminated on the back surface and the side surface, and obtaining the N-type substrate layer with the front surface comprising the emitter layer and the borosilicate glass layer, wherein the sheet resistance of the emitter layer is 60 omega;

(3) and (3) carrying out the following chemical oxidation on the back surface of the N-type substrate layer with the front surface comprising the emitter layer and the borosilicate glass layer obtained in the step (2) in sequence: a. performing first-step chemical oxidation in an aqueous solution of concentrated sulfuric acid and hydrogen peroxide (wherein the concentration of the hydrogen peroxide is 1 wt%, and the concentration of the concentrated sulfuric acid is 80 wt%) at 110 ℃ for 5 min; b. performing second-step chemical oxidation in aqueous solution of hydrogen peroxide and ammonia water (wherein, the concentration of hydrogen peroxide is 1 wt%, and the concentration of ammonia water is 10 wt%) at 80 deg.C for 5 min; c. carrying out a third step of chemical oxidation in an aqueous solution of hydrogen peroxide and hydrochloric acid (the concentration of hydrogen peroxide is 1 wt%, and the concentration of hydrochloric acid is 10 wt%) at 80 ℃ for 5 min; performing thermal oxidation at 500 ℃ for 20min, growing to obtain an N-type substrate layer with an oxide layer on the back surface, depositing polycrystalline silicon on the surface of the oxide layer by a chemical vapor deposition method under the condition that the pressure is 50mTorr, performing phosphorus diffusion in three steps under the condition that a phosphorus source is phosphorus oxychloride, performing first source-through deposition for 40min at 700 ℃ in phosphorus oxychloride with the flow rate of 1000sccm in the first step, performing propulsion treatment for 50min at 800 ℃ in nitrogen with the flow rate of 5000sccm in the second step, and performing second source-through deposition for 8min at 700 ℃ in phosphorus oxychloride with the flow rate of 50sccm in the third step to obtain the N-type substrate layer with the doped layer;

(4) removing the phosphosilicate glass layer on the front surface of the N-type substrate layer with the doped layer obtained in the step (3) by using a hydrofluoric acid solution etching method with the concentration of 2% for the first time, then removing the polycrystalline silicon wound and plated on the front surface of the N-type substrate layer with the doped layer by using a potassium hydroxide solution etching method with the concentration of 30% for the second time, and finally removing the borosilicate glass layer on the front surface of the N-type substrate layer with the doped layer and the phosphosilicate glass layer on the back surface by using a hydrofluoric acid etching method with the concentration of 5% for the second time to obtain the N-type substrate layer with the silicon oxide layer and the polycrystalline silicon doped layer on the back surface, wherein the square resistance of the polycrystalline silicon doped layer;

(5) forming an aluminum oxide passivation layer with the thickness of 2nm on the front side of the processed N-type substrate layer with the silicon oxide layer and the N-type polycrystalline silicon layer on the back side obtained in the step (4) by an atomic layer deposition method, then forming a silicon nitride antireflection layer with the thickness of 200nm and the refractive index of 1.9 by a plasma chemical vapor deposition method, and forming a silicon nitride protection layer with the thickness of 50nm on the back side by the plasma chemical vapor deposition method to obtain the N-type substrate layer with a passivation structure;

(6) and (4) firstly carrying out screen printing on the N-type substrate layer with the passivation structure obtained in the step (5), and then sintering for 100s at 700 ℃ to form a front Ag-Al electrode layer and a back Ag electrode layer, thus obtaining the passivation contact battery.

A passivated contact cell was prepared according to the above preparation method, the structure of the passivated contact cell being the same as in example 1;

wherein the thickness of the N-type substrate layer is 120 mu m; the emitter layer is a P + emitter layer; the thickness of the P + emitter layer is 2 μm; the oxidation passivation layer is an aluminum oxide passivation layer; the thickness of the aluminum oxide passivation layer is 2 nm; the anti-reflection layer is a silicon nitride anti-reflection layer; the thickness of the antireflection layer is 200 nm; the refractive index of the anti-reflection layer is 1.9; the front electrode layer is an Ag-Al electrode layer; the thickness of the front electrode layer is 10 μm; the oxide layer is a silicon oxide layer; the thickness of the silicon oxide layer is 1 nm; the thickness of the polycrystalline silicon doped layer is 300 nm; the protective layer is a silicon nitride layer; the thickness of the silicon nitride layer is 50 nm; the back electrode layer is a silver electrode layer; the thickness of the silver electrode layer was 20 μm.

Example 3

This example provides a method for preparing a passivated contact cell, comprising the steps of:

(1) carrying out texture etching on an N-type substrate layer (a phosphorus-doped monocrystalline silicon wafer) in advance, then carrying out boron diffusion on the textured N-type substrate layer in three steps, wherein in the first step, in boron tribromide with the flow rate of 1000sccm, source deposition is carried out at the temperature of 950 ℃ for 30min, in the second step, in nitrogen with the flow rate of 10slm, propulsion treatment is carried out at the temperature of 1100 ℃ for 40min, in the third step, under the condition that oxygen with the flow rate of 10slm, oxidation treatment is carried out at the temperature of 1000 ℃ for 100min, and the N-type substrate layer with an emitter layer and a borosilicate glass layer sequentially laminated on the front surface, the back surface and the side surface is obtained;

(2) carrying out hydrofluoric acid etching treatment with the concentration of 10% on the N-type substrate layers with the emitter layer and the borosilicate glass layer sequentially laminated on the front surface, the back surface and the side surface obtained in the step (1) to remove the emitter layer and the borosilicate glass layer sequentially laminated on the back surface and the side surface, and obtaining the N-type substrate layer with the front surface comprising the emitter layer and the borosilicate glass layer, wherein the sheet resistance of the emitter layer is 150 omega;

(3) and (3) carrying out the following chemical oxidation on the back surface of the N-type substrate layer with the front surface comprising the emitter layer and the borosilicate glass layer obtained in the step (2) in sequence: a. performing first-step chemical oxidation in an aqueous solution of concentrated sulfuric acid and hydrogen peroxide (wherein the concentration of the hydrogen peroxide is 10 wt% and the concentration of the concentrated sulfuric acid is 50 wt%) at 70 ℃ for 15 min; b. performing second-step chemical oxidation in aqueous solution of hydrogen peroxide and ammonia water (wherein, the concentration of hydrogen peroxide is 10 wt%, and the concentration of ammonia water is 1 wt%) at 60 deg.C for 15 min; c. carrying out a third step of chemical oxidation in an aqueous solution of hydrogen peroxide and hydrochloric acid (the concentration of hydrogen peroxide is 10 wt% and the concentration of hydrochloric acid is 1 wt%) at 60 ℃ for 15 min; carrying out thermal oxidation at the temperature of 600 ℃ for 2min, growing to obtain an N-type substrate layer with an oxide layer on the back surface, depositing polycrystalline silicon on the surface of the oxide layer by a chemical vapor deposition method under the condition that the pressure is 500mTorr, carrying out phosphorus diffusion in three steps under the condition that a phosphorus source is phosphorus oxychloride, carrying out first source-through deposition for 20min at the temperature of 800 ℃ in phosphorus oxychloride with the flow of 100sccm in the first step, carrying out propulsion treatment for 30min at the temperature of 1000 ℃ in nitrogen with the flow of 500sccm in the second step, carrying out second source-through deposition for 3min at the temperature of 800 ℃ in phosphorus oxychloride with the flow of 500sccm in the third step, and obtaining the N-type substrate layer with the doped layer to obtain the N-type substrate layer with the doped layer;

(4) removing the phosphosilicate glass layer on the front surface of the N-type substrate layer with the doped layer obtained in the step (3) by using a hydrofluoric acid solution etching method with the concentration of 10% for the first time, then removing the polycrystalline silicon wound and plated on the front surface of the N-type substrate layer with the doped layer by using a potassium hydroxide solution etching method with the concentration of 10%, and finally removing the borosilicate glass layer on the front surface of the N-type substrate layer with the doped layer and the phosphosilicate glass layer on the back surface by using a hydrofluoric acid etching method with the concentration of 20% for the second time to obtain the N-type substrate layer with the silicon oxide layer and the polycrystalline silicon doped layer on the back surface, wherein the sheet resistance of the polycrystalline silicon doped layer is 200 omega;

(5) forming an aluminum oxide passivation layer with the thickness of 20nm on the front side of the processed N-type substrate layer with the silicon oxide layer and the N-type polycrystalline silicon layer on the back side obtained in the step (4) by an atomic layer deposition method, then forming a silicon nitride antireflection layer with the thickness of 50nm and the refractive index of 2.2 by the atomic layer deposition method, and forming a protection layer with the thickness of 200nm on the back side by a plasma chemical vapor deposition method to obtain the N-type substrate layer with the passivation structure;

(6) and (4) firstly carrying out screen printing on the N-type substrate layer with the passivation structure obtained in the step (5), and then sintering for 10s at 850 ℃ to form a front Ag-Al electrode layer and a back Ag electrode layer, thus obtaining the passivation contact battery.

A passivated contact cell was prepared by the above preparation method, and the structure of the passivated contact cell was the same as in example 1;

wherein the thickness of the N-type substrate layer is 180 mu m; the emitter layer is a P + emitter layer; the thickness of the P + emitter layer is 0.2 μm; the oxidation passivation layer is an aluminum oxide passivation layer; the thickness of the aluminum oxide passivation layer is 20 nm; the anti-reflection layer is a silicon nitride anti-reflection layer; the thickness of the anti-reflection layer is 50 nm; the refractive index of the anti-reflection layer is 2.2; the front electrode layer is an Ag-Al electrode layer; the thickness of the front electrode layer is 30 μm; the oxide layer is a silicon oxide layer; the thickness of the silicon oxide layer is 3 nm; the thickness of the polycrystalline silicon doping layer is 50 nm; the protective layer is a silicon nitride layer; the thickness of the silicon nitride layer is 200 nm; the back electrode layer is a silver electrode layer; the thickness of the silver electrode layer was 5 μm.

Example 4

The only difference from example 1 is that the chemical oxidation only includes the first step of chemical oxidation, and the rest of the composition and the preparation method are the same as those of example 1.

Example 5

The only difference from example 1 is that the chemical oxidation only includes the second step chemical oxidation, and the rest of the composition and the preparation method are the same as example 1.

Example 6

The only difference from example 1 is that the chemical oxidation only includes the third step of chemical oxidation, and the rest of the composition and the preparation method are the same as those of example 1.

Example 7

The only difference from example 1 is that the chemical oxidation includes only the first step chemical oxidation and the second step chemical oxidation, and the rest of the composition and the preparation method are the same as those of example 1.

Example 8

The only difference from example 1 is that the chemical oxidation includes only the first and third chemical oxidations, and the rest of the composition and the preparation method are the same as example 1.

Example 9

The only difference from example 1 is that the chemical oxidation includes only the second and third chemical oxidations, and the rest of the composition and the preparation method are the same as example 1.

Comparative example 1

The difference from embodiment 1 is that only chemical oxidation is included in the formation of the oxide layer, thermal oxidation is not included, and the rest of the structure and the preparation method are the same as those of embodiment 1.

Comparative example 2

The difference from embodiment 1 is that the formation of the oxide layer does not include chemical oxidation, and only includes thermal oxidation, and the rest of the structure and the preparation method are the same as those of embodiment 1.

The passivated contact cells obtained from examples 1-9 and comparative examples 1-2 were tested for performance and the results are shown in table 1:

TABLE 1

In table 1:

wherein, the voltage (V), the current (A) and the filling factor (%) are the corresponding voltage, current and filling factor given in the table 1; the area of the battery is 244.32 square centimeters; the voltage (V) and the current (A) are the voltage and the current generated by the battery under the irradiation of 1000W light intensity, the model of the adopted testing machine is German Halm-2400, and the model of the testing software is 18-KW 05; the fill factor is the ratio of the maximum output power of the battery to the product of the short circuit current and the open circuit voltage.

As can be seen from table 1, the passivated contact cells prepared according to the present invention have higher light conversion efficiency; as can be seen from the comparison of example 1 and examples 4 to 6, when the chemical oxidation includes only one of the three-step chemical oxidation, the oxide layer thickness is too thin, resulting in too low Isc and Voc, resulting in a decrease in cell efficiency; as can be seen from the comparison of example 1 and examples 7 to 9, when the chemical oxidation includes only two of the three-step chemical oxidation, the oxide layer thickness is too thin, resulting in too low Voc, resulting in a decrease in the efficiency of the battery; as can be seen from the comparison between example 1 and comparative example 1, when the formation process of the oxide layer only includes chemical oxidation, not thermal oxidation, the thickness of the oxide layer is too thin and the uniformity of the silicon wafer surface is poor, resulting in too low Isc and Voc, resulting in a decrease in cell efficiency; as can be seen from the comparison of example 1 and comparative example 2, when the oxide layer formation process includes only thermal oxidation, not chemical oxidation, the oxide layer thickness is too thin and the surface cleanliness is poor, resulting in too low Isc and Voc.

The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.