CN102282682A - Solution for increasing wafer sheet resistance and/or photovoltaic cell power density level - Google Patents

Abstract

The present invention provides a method for the processing of thin film amorphous or monocrystalline or polycrystalline silicon wafer substrates having at least one pn or np junction and A portion of the phosphosilicate or borosilicate glass layer thereby increasing at least one of (a) the sheet resistance of the wafer and (b) the power density level of a photovoltaic cell fabricated from the wafer. The present invention also provides an acidic treatment solution comprising a buffered oxide etch (BOE) solution comprising at least one tetraalkylammonium hydroxide, acetic acid, at least one nonionic surfactant, at least one metal chelate A mixture, a metal-free source of ammonium, a metal-free source of fluoride ions and water, which are mixed with the oxidizing agent solution and optionally water.

Description

Solutions for increasing wafer sheet resistance and/or photovoltaic cell power density levels

technical field

The present invention relates to an acidic treatment composition and the use of such an acidic treatment composition in a method for the treatment of thin film amorphous or monocrystalline or polycrystalline silicon wafer substrates for use in photovoltaic cells, said wafer substrate being in the At least one pn or np junction and part of the phosphosilicate or borosilicate glass layer are present on the top surface to increase the sheet resistance of the wafer and/or the power density of photovoltaic cells fabricated from said wafer.

Background of the invention

Silicon-based solar cells, or photovoltaic cells, require multiple process steps to convert incident light into electrical current. One of these steps involves creating the emitter, most commonly by thermal drive-in of phosphorous into a boron-doped silicon wafer. This process creates a so-called dead layer, which results in a high recombination rate of generated charges and is detrimental to the power density level of the solar cell. In addition, the process creates a so-called phosphosilicate glass (PSG) layer on top of the wafer, which contains phosphorus, silicon and oxygen, and which must be removed for cell fabrication. After the thermal drive-in process, the phosphorous depth profile exhibits a plateau of high concentration extending from the surface to a depth of tens or hundreds of nanometers (depending on process conditions). Ideally, the concentration near the surface would be high (ie, 10 ^20-21 atoms/cm ³ ), allowing good contact with the electrodes.

A major goal of polycrystalline photovoltaic cell producers is to reduce the cost of the energy delivered by solar cells. This is generally accomplished in one of two ways: reducing overall cell manufacturing costs and/or increasing solar cell conversion efficiency. To achieve the latter goal, the current fabrication process uses a post-emitter etch process after phosphorous diffusion to remove the PSG layer by immersing the wafer in HF. Previous experiments have shown that additional treatment after HF soaking can lead to higher cell efficiencies, up to 0.3% absolute. A current product of Mallinckrodt Baker, Inc. (ie product PV-160) is used in this additional step. However, use of such products generally requires processing of wafer substrates in the product's heated bath (70°C or higher).

There is an urgent need to provide a composition that enables the etching of the residual PSG layer by improving the etching of the residual PSG layer in the same or less processing time and at reduced temperature compared to the results obtained with the currently used PV-160 products. And deeper etching of the dead layer yields higher power densities in solar cells.

Contents of the invention

In one embodiment of the invention, the invention provides a method of processing thin film amorphous or monocrystalline or polycrystalline silicon wafer substrates for use in photovoltaic cells, thereby increasing (a) the sheet resistance of the wafer and (b) the At least one of the power densities of photovoltaic cells fabricated on wafer substrates having pn or np junctions and/or partial phosphosilicate and/or borosilicate glass layers on the top surface of their wafer substrates , the processing method comprises contacting the wafer substrate with an acidic treatment solution at a sufficient temperature for a sufficient time to increase (a) the sheet resistance of the wafer and (b) the power density of a photovoltaic cell prepared from the wafer At least one, the solution comprises:

A buffered oxide etch (BOE) solution containing:

from about 0.1 to about 20% by weight of at least one tetraalkylammonium hydroxide,

about 0.1 to about 5% by weight acetic acid,

from about 0.1 to about 5% by weight of at least one nonionic surfactant,

from about 0.1 to about 5% by weight of at least one metal chelating agent,

About 0.1 to about 20% by weight of a metal free source of ammonium ions,

From about 0.01 to about 20% by weight of metal free source fluoride ions,

Add to 100% the balance water;

The buffered oxide etch (BOE) solution is mixed with an oxidizing agent and optionally water in a volume ratio of oxidizing agent/water/BOE solution of 0.01-10/0-100/1. A wafer with an emitter includes P-type silicon and N-type silicon.

Although this treatment may increase the sheet resistance of the wafer or the power density of the photovoltaic cell, it is preferred to increase both. In addition, the process can also increase the efficiency of photovoltaic cells fabricated from the wafer.

In another embodiment of the present invention, the present invention provides an acidic treatment solution for treating thin film amorphous or monocrystalline or polycrystalline silicon wafer substrates for use in photovoltaic cells, thereby increasing (a) the sheet resistance of said wafers and (b) at least one of the power density levels of photovoltaic cells fabricated from said wafer substrate having pn or np junctions and/or portions of phosphosilicate and / or a borosilicate glass layer, wherein the acidic treatment solution comprises a mixture of:

A buffered oxide etch (BOE) solution containing:

from about 0.1 to about 20% by weight of at least one tetraalkylammonium hydroxide,

about 0.1 to about 5% by weight acetic acid,

from about 0.1 to about 5% by weight of at least one nonionic surfactant,

from about 0.1 to about 5% by weight of at least one metal chelating agent,

from about 0.1 to about 20% by weight of a metal-free source of ammonium ions,

from about 0.01 to about 20% by weight of a metal-free source of fluoride ions,

Add to 100% the balance water;

The buffered oxide etch (BOE) solution is mixed with an oxidizing agent and optionally water in a volume ratio of oxidizing agent/water/BOE solution of 0.01-10/0-100/1. A wafer with an emitter includes P-type silicon and N-type silicon.

In both embodiments, the weight percent of tetraalkylammonium hydroxide in the BOE solution is preferably 0.5 to 15%, more preferably 1 to 10%, more preferably 1.5 to 8%, most preferably 2 to 4%, and Specifically 3.1%.

The weight percentage of acetic acid is preferably 0.5 to 4%, more preferably 0.8 to 3%, still more preferably 1 to 2%, most preferably 1 to 1.5%, and especially 1-2%.

As for the nonionic surfactant, its weight percentage is preferably 0.2 to 4%, more preferably 0.3 to 2%, further preferably 0.5 to 1%, most preferably 0.7 to 0.9%, and especially 0.8%.

For the chelating agent, its weight percentage is preferably 0.2 to 4%, more preferably 0.3 to 3%, more preferably 0.4 to 1%, most preferably 0.5 to 0.8%, and especially 0.6%.

As for the ammonium ion source, its weight percentage is preferably 0.2 to 10%, more preferably 0.3 to 5%, further preferably 0.5 to 2%, most preferably 0.6 to 1%, and especially 0.8%.

As for the fluoride ion source, its weight percentage is preferably 1 to 10%, more preferably 0.5 to 5%, further preferably 1.0 to 3%, most preferably 1.5 to 2.5%, and especially 2.1%.

While this treatment may increase the sheet resistance of the wafer or the power density of photovoltaic cells fabricated from the wafer, it is preferred to increase both. In addition, the process can also increase the efficiency of photovoltaic cells fabricated from the wafer.

In a preferred embodiment of the invention, the treatment is carried out at a temperature of from about 20°C to less than 70°C.

In another preferred embodiment of the present invention, the pH of the BOE solution is about 3 to less than 7, preferably about 3 to about 6, more preferably about 4.3 to about 5.

In yet another preferred embodiment of the invention, the oxidizing agent comprises hydrogen peroxide. Generally, the oxidizing agent is water and hydrogen peroxide in the form of an aqueous solution (0.01% to 50%, more preferably 0.1% to 30%, even more preferably about 30%) in any suitable proportion, usually A ratio of about 6/10.2 to about 6/1.

In yet another preferred embodiment of the present invention, the BOE solution comprises tetramethylammonium hydroxide as said tetraalkylammonium hydroxide, 3,5-dimethylhex-1-yn-3-ol as said at least one surfactant, and EDTA as the at least one metal chelating agent, and the oxidizing agent solution comprises hydrogen peroxide and water.

In yet another preferred embodiment of the present invention, the BOE solution comprises about 3.1% tetramethylammonium hydroxide, about 1.2% acetic acid, about 2.1% HF, about 0.8% 3,5-dimethylhexyl -1-yn-3-ol, about 0.8% ammonium hydroxide, about 0.6% EDTA, and about 91.5% water, where the percentages are by weight.

In yet another preferred embodiment of the present invention, the BOE solution is mixed with the oxidizing agent solution in a ratio of BOE/water/hydrogen peroxide of about 1/6/0.2. In another preferred embodiment of the present invention, the BOE solution is mixed with the oxidizing agent solution in a ratio of BOE/water/hydrogen peroxide of about 1/6/0.8. In another preferred embodiment of the present invention, the BOE solution is mixed with the oxidizing agent solution in a ratio of BOE/water/hydrogen peroxide of about 1/6/1.

In yet another preferred embodiment of the present invention, this embodiment comprises a combination of one or more of the above preferred embodiments.

Additionally, the present invention can be used at processing temperatures of from about 20°C to about 40°C, which is lower than the current industry standard of 70°C.

Detailed description of the invention

The present invention provides a method of processing thin film amorphous or monocrystalline or polycrystalline silicon wafer substrates for use in photovoltaic cells, thereby improving (a) the sheet resistance of the wafers and (b) the power density of photovoltaic cells fabricated from said wafers At least one of the wafer substrates has a pn junction or np junction and/or part of a phosphosilicate and/or borosilicate glass layer on the top surface of the wafer substrate, the method comprising making the wafer contacting the substrate at a temperature and for a sufficient time with an acidic treatment solution comprising:

A buffered oxide etch (BOE) solution containing:

from about 0.1 to about 20% by weight of at least one tetraalkylammonium hydroxide,

about 0.1 to about 5% by weight acetic acid,

from about 0.1 to about 5% by weight of at least one nonionic surfactant,

from about 0.1 to about 5% by weight of at least one metal chelating agent,

from about 0.1 to about 20% by weight of a metal-free source of ammonium ions,

from about 0.01 to about 20% by weight of a metal-free source of fluoride ions,

Add to 100% the balance water;

The buffered oxide etch (BOE) solution is mixed with an oxidizing agent and optionally water in a volume ratio of oxidizing agent/water/BOE solution of 0.01-10/0-100/1. Wafers with emitters include both p- and n-source silicon types.

While this treatment may increase the sheet resistance of the wafer or the power density of photovoltaic cells fabricated from the wafer, it is preferred to increase both. In addition, the process can also increase the efficiency of photovoltaic cells fabricated from the wafer.

Similarly, the present invention provides a solution for treating thin film amorphous or monocrystalline or polycrystalline silicon wafer substrates for use in photovoltaic cells, thereby increasing (a) the sheet resistance of said wafers and (b) At least one of the power density levels of photovoltaic cells having a wafer substrate having a pn or np junction and/or a partial phosphosilicate and/or borosilicate glass layer on the top surface of its wafer substrate, Wherein said acidic treatment solution comprises the following mixture:

A buffered oxide etch (BOE) solution containing:

from about 0.1 to about 20% by weight of at least one tetraalkylammonium hydroxide,

about 0.1 to about 5% by weight acetic acid,

from about 0.1 to about 5% by weight of at least one nonionic surfactant,

from about 0.1 to about 5% by weight of at least one metal chelating agent,

from about 0.1 to about 20% by weight of a metal-free source of ammonium ions,

from about 0.01 to about 20% by weight of a metal-free source of fluoride ions,

Add to 100% the balance water;

The buffered oxide etch (BOE) solution is mixed with an oxidizer and optionally water in a ratio of 0.01-10/0-100/1 oxidizer/water/BOE solution. A wafer with an emitter includes P-type silicon and N-type silicon.

While this treatment may increase the sheet resistance of the wafer or the power density of photovoltaic cells fabricated from the wafer, it is preferred to increase both. In addition, the process can also increase the efficiency of photovoltaic cells fabricated from the wafer.

In the process of the present invention, the step of applying an acidic treatment solution follows the removal of phosphosilicate or borosilicate glass (incomplete removal) with HF, and just after the immersion with HF again and the subsequent antireflective coating (AntiReflective coating). Coating, ARC) (such as SiNxH deposition), applied on the photovoltaic wafer substrate. The method includes exposing the wafer substrate to the acidic treatment solution at a temperature sufficient, such as by immersing the wafer substrate in a heating bath of the solution for a sufficient time to increase (a) the sheet resistance of the wafer and (b) At least one of power density of photovoltaic cells fabricated from the wafer. The contact of the wafer substrate with the acidic treatment solution typically lasts from about 0.01 to about 20 minutes, preferably from about 0.5 to about 5 minutes, more preferably about 1 minute. The temperature of the solution is generally from about 20°C to less than about 70°C, preferably from about 20°C to about 60°C, more preferably from about 20°C to about 40°C, even more preferably about 40°C.

Tetraalkylammonium hydroxides of the formula [(R) ₄ N ⁺ ] _p [X ^−q ] or salts thereof, wherein each R is independently a substituted or unsubstituted alkyl A group, preferably an alkyl group having 1 to 22, more preferably 1 to 6, most preferably 1 carbon atoms, and X=OH or a suitable salt anion such as carbonate etc.; p and q are equal and are 1 Integers up to 3. Among them, tetramethylammonium hydroxide and trimethyl-2-hydroxyethylammonium hydroxide (choline) are most preferred. Examples of other useful quaternary ammonium hydroxides include trimethyl-3-hydroxypropyl ammonium hydroxide, trimethyl-3-hydroxybutyl ammonium hydroxide, trimethyl-4-hydroxybutyl ammonium hydroxide, triethyl- 2-Hydroxyethylammonium Hydroxide, Tripropyl-2-Hydroxyethylammonium Hydroxide, Tributyl-2-Hydroxyethylammonium Hydroxide, Dimethylethyl-2-Hydroxyethylammonium Hydroxide, Dimethylbis(2-hydroxyethyl)ammonium hydroxide, monomethyltris(2-hydroxyethyl)ammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, mono Methyltriethylammonium Hydroxide, Monomethyltripropylammonium Hydroxide, Monomethyltributylammonium Hydroxide, Monoethyltrimethylammonium Hydroxide, Monoethyltributylammonium Hydroxide, Dimethyldiethylammonium Hydroxide Ammonium hydroxide, dimethyl dibutyl ammonium hydroxide, etc., and mixtures thereof.

The source of metal-free ammonium ions may be any suitable metal-free ammonium salt, such as ammonium hydroxide, ammonium fluoride, ammonium chloride, ammonium nitrate, etc., but ammonium hydroxide is preferred. The metal-free fluoride ion source can be any suitable metal-free fluoride compound, such as hydrogen fluoride, ammonium fluoride, quaternary ammonium fluoride such as tetramethylammonium fluoride. Preferably, the metal-free source of fluoride ions is HF. In another preferred embodiment, the ammonium and fluoride ions can be provided by one compound, ammonium fluoride.

或任何其他

表面活性剂，氟化的烷基聚氧乙烯乙醇类，特别是

FC-170C，和亚烷基二醇单烷基醚，特别是丁氧基丙醇。The acidic treating solution of the present invention may contain any suitable nonionic surfactant. Among the various suitable nonionic surfactants for use in the treatment composition according to the invention, mention may be made, for example, of low foaming nonionic surfactants, such as acetylenic alcohol surfactants, fluorinated surfactants agents, such as fluorinated alkyl alkoxylates such as FC-171, fluorinated alkyl esters such as FC-430 and FC-431, and fluorinated polyoxyethylene alkanols such as FC-170C, fatty acid esters of polyols, polyoxyethylene monoalkyl ethers, polyoxyethylene glycols, silicone-type surfactants and alkylene glycol monoalkyl ethers, such as butoxypropanol. Preferred for use as nonionic surfactants in the acidic treatment compositions of the present invention are acetylenic alcohol surfactants, especially 3,5-dimethylhex-1-yn-3-ol

or any other

Surfactants, fluorinated alkylpolyoxyethylene alcohols, especially

FC-170C, and alkylene glycol monoalkyl ethers, especially butoxypropanol.

Any suitable metal chelating agent that increases the capacity of the formulation to hold metals in solution can be used in the acidic treating compositions of the present invention. Typical examples of chelating agents used for this purpose are the following organic acids and their salts: ethylenediaminetetraacetic acid (EDTA), butylenediaminetetraacetic acid, cyclohexane-1,2-diaminetetraacetic acid (CyDTA) , diethylenetriaminepentaacetic acid, ethylenediaminetetrapropionic acid, (hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), methyliminodiacetic acid, propylenediaminetetraacetic acid, nitrilotriacetic acid (NTA ), citric acid, tartaric acid, gluconic acid, glucaric acid, glyceric acid, oxalic acid, phthalic acid, maleic acid, mandelic acid, malonic acid, lactic acid, salicylic acid, catechol, 8-hydroxy Quinoline, N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid), etc.

Any suitable oxidizing agent may be used, e.g., oxidizing anions such as peroxide, nitric acid and its salts, and ammonium nitrate, persulfate, periodate, perbromate, perchlorate, iodic acid Salt, bromate and chlorate. Preference is given to peroxides, especially hydrogen peroxide.

The acid treatment compositions of the present invention can be prepared by mixing the required ingredients in a suitable container to form the composition. Preferably, the desired components of the composition are added to the vessel in the order base/acid/base/acid so as to minimize the heat generated by the reaction of the ingredients.

However, in the manufacture of solar cells, this product not only etches silicon oxide, but also silicon and phosphorus. For this purpose, BOE needs to be mixed with hydrogen peroxide as an oxidizing agent. This means that in the etch-oxidation sequence, the BOE etches away the silicon oxide while the oxidizing agent generates new silicon oxide on the surface. Furthermore, the oxidizing agent oxidizes the phosphorus present in the layer, thereby dissolving it. Etched species (including but not limited to metallic impurities) are partially retained in solution by the addition of chelating agents, while the wettability of the surface (ie, the efficiency with which the oxidizing agent is able to oxidize the surface) is improved by the addition of surfactants. The addition of acetic acid ensures a doubly buffered system, which contributes to process stability.

The invention will be illustrated by, but not limited to, the following examples. In these examples, percentages are by weight.

Example 1

A set of 25 contiguous polysilicon wafers (about 15.6 x 15.6 cm ² in size and about 180-200 μm thick) were processed in an industrial type in-line photovoltaic cell production process. After deposition of the emitter and removal of the phosphorous glass with HF, the wafer having a partial phosphorosilicate glass layer on the top surface of the wafer substrate was exposed to (1) the acidic treatment solution of the present invention at 40°C; (2) The PV-160 solution of the prior art, the solution is required to be at 70°C; or (3) no treatment solution, as a control. The acidic treatment solution of the present invention comprises a BOE solution comprising about 3.1% tetramethylammonium hydroxide, about 1.2% acetic acid, about 2.1% HF, about 0.8% 3,5-dimethylhexyl-1- Alkyn-3-ol, about 0.8% ammonium hydroxide, about 0.6% EDTA, about 91.5% water. The BOE solution was mixed with the hydrogen peroxide oxidizer solution in a ratio of about 1/6/0.2 BOE/water/30% hydrogen peroxide solution. The prior art PV-160 solution was also mixed with the hydrogen peroxide oxidant solution in a ratio of about 1/6/0.2 BOE/water/30% hydrogen peroxide solution. The treated wafers were then wet-chemically treated in a 1 wt% HF solution at room temperature for 1 min, followed by common photovoltaic fabrication steps to fabricate the desired photovoltaic cells. Keep the Electrode firing setting constant while processing the different groups and set the prior art group to the best firing setting. The power density level (in mW/cm ² , defined as the product of short-circuit current density and open-circuit voltage, Jsc×Voc) of each battery was measured. The results are shown in Table 1 below.

Table 1

Example 2

A set of 25 contiguous polysilicon wafers (about 15.6 x 15.6 ^cm2 in size and about 180-200 μm thick) were processed in an industrial line photovoltaic production process. After emitter deposition and removal of the phosphorous glass with HF, the wafer has a partial phosphorosilicate glass layer on the top surface of the wafer substrate, the wafer is exposed at 40°C to (1) the acidic treatment solution of the present invention; (2) now There is a technical PV-160 solution, which requires a temperature of 70°C. The treatment solution of the present invention comprises a BOE solution comprising about 3.1% tetramethylammonium hydroxide, about 1.2% acetic acid, about 2.1% HF, about 0.8% 3,5-dimethylhex-1-yne -3-ol, about 0.8% ammonium hydroxide, about 0.6% EDTA, about 91.5% water. The BOE solution was mixed with the hydrogen peroxide oxidizer solution in a ratio of BOE/water/30% hydrogen peroxide of about 1/6/0.8. The prior art PV-160 solution was also mixed with the hydrogen peroxide oxidant solution in a ratio of about 1/6/0.2 BOE/water/30% hydrogen peroxide solution. The treated wafers were then wet-chemically treated in a 1 wt% HF solution at room temperature for 1 min, followed by common photovoltaic fabrication steps to fabricate the desired photovoltaic cells. Keep the electrode discharge settings constant while processing the different groups and set the prior art group to the optimal discharge setting. The power density level (in mW/cm ² , defined as the product of short-circuit current density and open-circuit voltage, Jsc×Voc) of each battery was measured. The results are shown in Table 2 below.

Table 2

Example 3

A set of 25 contiguous polysilicon wafers (about 15.6 x 15.6 ^cm2 in size and about 180-200 μm thick) were processed in an industrial line photovoltaic production process. After emitter deposition and removal of the phosphorous glass with HF, the wafer has a partial phosphorosilicate glass layer on the top surface of the wafer substrate, and the wafer is exposed to (1) the acidic treatment of the present invention at 25°C, 30°C and 40°C solution; (2) PV-160 solution of the prior art, which requires a temperature of 70° C.; or (3) no treatment solution, as a control. The acidic treatment solution of the present invention comprises a BOE solution comprising about 3.1% tetramethylammonium hydroxide, about 1.2% acetic acid, about 2.1% HF, about 0.8% 3,5-dimethylhexyl-1- Alkyn-3-ol, about 0.8% ammonium hydroxide, about 0.6% EDTA, about 91.5% water. The BOE solution was mixed with the hydrogen peroxide oxidizer solution in a ratio of about 1/6/1 BOE/water/30% hydrogen peroxide solution. The prior art PV-160 solution was also mixed with the hydrogen peroxide oxidizer solution in a ratio of about 1/6/0.2 BOE/water/hydrogen peroxide solution. The treated wafers were then wet-chemically treated in a 1 wt% HF solution at room temperature for 1 min, followed by common photovoltaic fabrication steps to fabricate the desired photovoltaic cells. Keep the electrode discharge settings constant while processing the different groups and set the prior art group to the optimal discharge setting. The results are shown in Table 3 below.

table 3

As shown by these results, the compositions of the present invention significantly increased the sheet resistance and/or power density of the battery compared to the control. By changing the mixing ratio, especially by increasing the amount of hydrogen peroxide, the composition of the present invention shows equal or better power density than PV-160. However, the composition of the present invention is able to achieve this at a temperature range of 20°C to 40°C, whereas the PV-160 composition requires 70°C for this purpose.

Although the present invention has been described with reference to specific embodiments of the invention, it should be understood that various changes, modifications or variations may be made without departing from the spirit and scope of the invention. Accordingly, the present invention is intended to embrace all such alterations, improvements or variations that fall within the spirit and scope of the claims.

Claims (23)

1. the processing method that is used for the film of photocell amorphous or monocrystalline or polycrystalline silicon wafer substrate, described wafer substrates has at least a in pn knot or np knot and part phosphosilicate or the borosilicate glass layer on the end face of its wafer substrates, thereby increase (a) sheet resistance and (b) at least one in the photronic power density, described method comprises makes wafer substrates contact time enough with acidic treatment solution with the sheet resistance that increases (a) described wafer and (b) at least one in the photronic power density of described wafer preparation under enough temperature, and described acidic treatment solution comprises:

Buffered oxide etch (BOE) solution that contains following composition:

About 0.1 at least a tetra-alkyl ammonium hydroxide to about 20 weight %,

About 0.1 acetate to about 5 weight %,

About 0.1 at least a nonionic surface active agent to about 5 weight %,

About 0.1 at least a metal-chelator to about 5 weight %,

About 0.1 metal-free ammonium ion source to about 20 weight %,

About 0.01 metal-free fluoride sources to about 20 weight %,

Add to 100% excess water;

This buffered oxide etch (BOE) solution mixes with the ratio of oxidizing agent solution/water/BOE solution of 0.01-10/0-100/1 with oxidizing agent solution and the water of choosing wantonly.

2. according to the process of claim 1 wherein that described processing carries out to about 70 ℃ temperature at about 20 ℃.

3. according to the method for claim 1 or 2, the pH value of wherein said BOE solution is about 3 to about 6.

4. according to the method for claim 3, the pH value of wherein said BOE solution is 4.3 to about 5.

5. according to each method in the aforementioned claim, wherein said oxidizing agent solution comprises hydrogen peroxide.

6. according to each method in the aforementioned claim, wherein said BOE solution comprises the Tetramethylammonium hydroxide as described tetra-alkyl ammonium hydroxide, as 3 of described at least a surfactant, the 5-dimethyl oneself-1-alkynes-3-alcohol, with the EDTA as described at least a metal-chelator, and described oxidizing agent solution comprises hydrogen peroxide and water.

7. according to the method for claim 6, wherein said BOE solution comprise about 3.1% Tetramethylammonium hydroxide, about 1.2% acetate, about 2.1% HF, about 0.8% 3, the 5-dimethyl oneself-1-alkynes-3-alcohol, about 0.8% ammonium hydroxide, about 0.6% EDTA and about 91.5% water.

8. method according to claim 7, wherein said BOE solution and oxidizing agent solution are that the ratio of BOE/ water/30% hydrogen peroxide of 1/6/0.2-1.0 is mixed with the scope.

9. according to the method for claim 7, wherein said BOE solution and oxidizing agent solution mix with the ratio that is about BOE/ water/30% hydrogenperoxide steam generator of 1/6/0.2.

10. according to the method for claim 7, wherein said BOE solution and oxidizing agent solution mix with the ratio that is about BOE/ water/30% hydrogenperoxide steam generator of 1/6/0.8.

11. according to the method for claim 7, wherein said BOE solution and oxidizing agent solution mix with the ratio that is about BOE/ water/30% hydrogenperoxide steam generator of 1/6/1.

12. according to the method for claim 9, wherein said processing is carried out to about 70 ℃ temperature at about 20 ℃.

13. according to each method in the aforementioned claim, wherein said processing has also improved the photronic efficient of being made by this wafer.

14. handle the acidic treatment solution of the film be used for photocell amorphous or monocrystalline or polycrystalline silicon wafer substrate, described wafer substrates has at least a in pn knot or np knot and part phosphosilicate or the borosilicate glass layer on the end face of its wafer substrates, by at least one in the photronic power density of described wafer manufacturing, thereby described acidic treatment solution comprises following mixture to the sheet resistance of increase (a) described wafer with (b):

Buffered oxide etch (BOE) solution that contains following composition:

About 0.1 at least a tetra-alkyl ammonium hydroxide to about 20 weight %,

About 0.1 acetate to about 5 weight %,

About 0.1 at least a nonionic surface active agent to about 5 weight %,

About 0.1 at least a metal-chelator to about 5 weight %,

About 0.1 metal-free ammonium ion source to about 20 weight %,

About 0.01 metal-free fluoride sources to about 20 weight %,

Add to 100% excess water;

This buffered oxide etch (BOE) solution mixes with the ratio of oxidizing agent solution/water/BOE solution of 0.01-10/0-100/1 with oxidizing agent solution and the water of choosing wantonly.

15. acidic treatment solution according to claim 14, the pH value of wherein said BOE solution are about 3 to about 6.

16. acidic treatment solution according to claim 15, the pH value of wherein said BOE solution are about 4.3 to about 5.

17. according to each described acidic treatment solution in the claim 14 to 15, wherein said oxidizing agent solution comprises hydrogen peroxide.

18. according to each described acidic treatment solution in the claim 14 to 17, wherein said BOE solution comprises the Tetramethylammonium hydroxide as described tetra-alkyl ammonium hydroxide, as 3 of described at least a surfactant, the 5-dimethyl oneself-1-alkynes-3-alcohol, with the EDTA as described at least a metal-chelator, and described oxidizing agent solution comprises hydrogen peroxide and water.

19. acidic treatment solution according to claim 18, wherein said BOE solution comprise about 3.1% Tetramethylammonium hydroxide, about 1.2% acetate, about 2.1% HF, about 0.8% 3, the 5-dimethyl oneself-1-alkynes-3-alcohol, about 0.8% ammonium hydroxide, about 0.6% EDTA and about 91.5% water.

20. being the ratio of BOE/ water/30% hydrogenperoxide steam generator of 1/6/0.2-1.0 with the scope, acidic treatment solution according to claim 19, wherein said BOE solution and oxidizing agent solution mixes.

21. acidic treatment solution according to claim 19, wherein said BOE solution and oxidizing agent solution mix with the ratio that is about BOE/ water/30% hydrogenperoxide steam generator of 1/6/0.2.

22. acidic treatment solution according to claim 19, wherein said BOE and oxidizing agent solution mix with the ratio that is about BOE/ water/30% hydrogenperoxide steam generator of 1/6/0.8.

23. acidic treatment solution according to claim 19, wherein said BOE and oxidizing agent solution mix with the ratio that is about BOE/ water/30% hydrogenperoxide steam generator of 1/6/1.