A kind of preparation method of black silicon suede structure
Technical field
The present invention relates to silicon solar cell field more particularly to a kind of preparation methods of black silicon suede structure.
Background technique
Black silicon solar cell is the etching method for solving the problems, such as polycrystalline diamond wire cutting in recent years.Black silicon solar cell
The process for etching of piece mainly have reactive ion etching method (RIE), mechanical carving groove technology, laser etching techniques, honeycomb flannelette technology,
Black silicon of metal inducement wet process (MCCE) etc..And MCCE method is to use one of the most common type method in current industry.Its technique is more
Simply, it is also easily commercially produced, which mainly includes heavy silver, borehole, reaming, also adulterates numerous washings among these
Step.The polysilicon chip reflectivity for disclosing a kind of reduction Buddha's warrior attendant wire cutting such as the patent application No. is 201410430817.2
Metal catalytic etching method, uses HNO3Reaming is carried out with HF, reuses lye and ammonium hydroxide, hydrogen peroxide to silicon wafer after reaming
Flannelette is modified, and honeycomb suede structure is formed;For another example application No. is one kind of 201710725370.5 patent disclosure to mention
The microstructure of the black silicon photoelectric conversion efficiency of high polycrystalline and component power, uses HNO3 and HF reaming, reuses XOH and carries out suede
Face modification, forming surface flannelette is honeycomb structure;For another example when Changzhou in the chambering process of the black silicon of wound-polycrystalline, using HNO3With
After HF and additive carry out first step reaming, reuses NaOH and additive carries out second of reaming, generate honeycomb flannelette
Surface texture.
But the black silicon reaming of wet process now uses HF and HNO3Or it adds the mixed liquor of additive together and carries out a step
Reaming, then use lye and H2O2The hole size generated on the flannelette of silicon wafer after the reaming modified its flannelette
Uniformity is relatively poor, and can not improve the uniformity of its hole size in modification, and it is micro- only to remove flannelette part
Structure.So that obtained silion cell open-circuit voltage becomes smaller, while but also series resistance Rs and fill factor FF is deteriorated.Cause
How this, improve process for etching and be desirably to obtain the uniform flannelette pattern of hole being of great significance.
Summary of the invention
In view of this, technical problem to be solved by the present invention lies in a kind of preparation method of black silicon suede structure is provided,
Black silicon flannelette hole provided by the invention is uniform, and inner wall smooth is smooth, so that having with its black silion cell prepared
Mechanical property.
The present invention provides a kind of preparation methods of black silicon suede structure, comprising:
1) it will be put into the mixed solution of nitric acid and hydrofluoric acid and react by the silicon wafer of heavy silver and borehole, obtain first step expansion
The silicon wafer in hole;
2) silicon wafer after first step reaming is put into hydrogen peroxide and the mixed solution of ammonium fluoride and is reacted, obtain second
The silicon wafer of reaming is walked,
Wherein, in the mixed solution of the hydrogen peroxide and ammonium fluoride, the mass percent concentration of the hydrogen peroxide is 7.5%
~12.5%;The mass percent concentration of the ammonium fluoride is 0.4%~1.1%;
3) silicon wafer of second step reaming is subjected to alkali cleaning, obtains the black silicon of making herbs into wool.
Preferably, in the step 1) in the mixed solution of nitric acid and hydrofluoric acid, the mass percent concentration of nitric acid is
34%~44.2%, the mass percent concentration of hydrofluoric acid is 3.4%~4.5%.
Preferably, the temperature reacted in the step 1) is 8~12 DEG C.
Preferably, the time reacted in the step 1) is 40~80S.
Preferably, in the mixed solution of the hydrogen peroxide and ammonium fluoride, the mass percent concentration of the hydrogen peroxide is
9.0%~10.5%;The mass percent concentration of the ammonium fluoride is 0.55%~0.7%.
Preferably, the temperature reacted in the step 2) is 8~12 DEG C.
Preferably, the time reacted in the step 2) is 100~360S.
Preferably, the alkali cleaning of the step 3) is specially to use KOH, NH3.H20 and H2O2Mixed solution obtains step 2)
The flannelette of silicon wafer carry out modification suede.
Preferably, described KOH, NH3.H2O and H2O2In mixed solution, the mass percent concentration of KOH is 1.8%~
3.8%, the NH3.H2The mass percent concentration of O is 0.5%~1.5%, the H2O2Mass percent concentration be
0.9%~2.1%.
Preferably, the temperature of the alkali cleaning is 30~45 DEG C.
Compared with prior art, the preparation method of black silicon suede structure provided by the invention, by the way that heavy silver will be passed through first
It is put into the mixed solution of nitric acid and hydrofluoric acid and reacts with the silicon wafer of borehole, obtain the silicon wafer of first step reaming;Then by first
Silicon wafer after step reaming, which is put into hydrogen peroxide and the mixed solution of ammonium fluoride, to be reacted, and obtains the silicon wafer of second step reaming, most
The silicon wafer of second step reaming is subjected to alkali cleaning afterwards, obtains the black silicon of making herbs into wool.Wherein, hydrogen peroxide used when second reaming of the present invention
In the mixed solution of ammonium fluoride, the mass percent concentration of the hydrogen peroxide is 7.5~12.5%;The quality of the ammonium fluoride
Percent concentration is 0.4%~1.1%;It being found through experiments that, the present invention carries out making herbs into wool to black silicon by using specific technique,
The suede structure Hole size of obtained black silicon is almost consistent, is suede structure with good uniformity, and the micro- knot of hole inner wall
Structure is smooth.
Detailed description of the invention
Fig. 1 is 15000 times of scanning electron microscope (SEM) photographs of the silicon wafer of making herbs into wool prepared by the embodiment of the present invention 1;
Fig. 2 is 20000 times of field emission scanning electron microscope figures of the silicon wafer of making herbs into wool prepared by the embodiment of the present invention 1;
Fig. 3 is 15000 times of scanning electron microscope (SEM) photographs of the silicon wafer of the making herbs into wool of comparative example 1 of the present invention preparation;
Fig. 4 is 20000 times of field emission scanning electron microscope figures of the silicon wafer of the making herbs into wool of comparative example 1 of the present invention preparation;
Fig. 5 is 15000 times of scanning electron microscope (SEM) photographs of the silicon wafer of the making herbs into wool of comparative example 2 of the present invention preparation;
Fig. 6 is 20000 times of field emission scanning electron microscope figures of the silicon wafer of the making herbs into wool of comparative example 2 of the present invention preparation.
Specific embodiment
The present invention provides a kind of preparation methods of black silicon suede structure, comprising:
1) it will be put into the mixed solution of nitric acid and hydrofluoric acid and react by the silicon wafer of heavy silver and borehole, obtain first step expansion
The silicon wafer in hole;
2) silicon wafer after first step reaming is put into hydrogen peroxide and the mixed solution of ammonium fluoride and is reacted, obtain second
The silicon wafer of reaming is walked,
Wherein, in the mixed solution of the hydrogen peroxide and ammonium fluoride, the mass percent concentration of the hydrogen peroxide is 7.5%
~12.5%;The mass percent concentration of the ammonium fluoride is 0.4%~1.1%;
3) silicon wafer of second step reaming is subjected to alkali cleaning, obtains the black silicon of making herbs into wool.
According to the present invention, the present invention will be put into the mixed solution of nitric acid and hydrofluoric acid by the silicon wafer of heavy silver and borehole first
Middle reaction obtains the silicon wafer of first step reaming;Wherein, in the mixed solution of the nitric acid and hydrofluoric acid, solvent is water, nitric acid
Mass percent concentration is preferably 34%~44.2%, and more preferably 35%~41%;The mass percent concentration of hydrofluoric acid is excellent
It is selected as 3.4%~4.9%, more preferably 3.9%~4.4%;The temperature of the reaction is preferably 8~12 DEG C, more preferably 9~
10 DEG C, the time of the reaction is preferably 40~80S, more preferably 50~60S;In the present invention, the present invention is to heavy silver and borehole
Method there is no a particular/special requirement, the method well known in the art due to black silicon heavy silver and borehole.
According to the present invention, the silicon wafer after first step reaming is also put into the mixed solution of hydrogen peroxide and ammonium fluoride by the present invention
It is reacted, obtains the silicon wafer of second step reaming, wherein in the mixed solution of the hydrogen peroxide and ammonium fluoride, solvent is water, institute
The mass percent concentration for stating hydrogen peroxide is preferably 9.0%~10.5%, and more preferably 9.6%~10.2%;The ammonium fluoride
Mass percent concentration be 0.4%~1.1%, more preferably 0.55%~0.8%;The temperature of the reaction is preferably 8~
12 DEG C, more preferably 10~11 DEG C, the time of the reaction is preferably 100~360S, more preferably 150~220S.
According to the present invention, the silicon wafer of second step reaming will also be carried out alkali cleaning by the present invention, obtain the black silicon of making herbs into wool;Wherein,
The temperature of the alkali cleaning is preferably 30~45 DEG C;The time of the alkali cleaning is preferably 2~4min.The alkali cleaning is specially to use
KOH、NH3.H2O and H2O2The flannelette for the silicon wafer that mixed solution obtains step 2) carries out modification suede, and then obtains the black of making herbs into wool
Silicon;Wherein, described KOH, NH3.H2O and H2O2In mixed solution, solvent is water, and the mass percent concentration of KOH is preferably
1.8%~3.8%, NH3.H2The mass percent concentration of O is preferably 0.5%~1.5%, H2O2Mass percent concentration it is excellent
It is selected as 0.9%~2.1%.
The present invention provides the preparation methods of black silicon suede structure, by will be put into first by the silicon wafer of heavy silver and borehole
It is reacted in the mixed solution of nitric acid and hydrofluoric acid, obtains the silicon wafer of first step reaming;Then the silicon wafer after first step reaming is put
Enter and reacted in hydrogen peroxide and the mixed solution of ammonium fluoride, obtain the silicon wafer of second step reaming, finally by second step reaming
Silicon wafer carries out alkali cleaning, obtains the black silicon of making herbs into wool.Wherein, the mixing of hydrogen peroxide and ammonium fluoride used when second reaming of the present invention is molten
In liquid, the mass percent concentration of the hydrogen peroxide is 7.5%~12.5%;The mass percent concentration of the ammonium fluoride is
0.7%~1.3%;The result shows that etching method provided by the invention can scabble the micro-structure generated inside flannelette by reaming,
And hole size consistency is good, can form flannelette pattern with good uniformity, and then form uniform P-N after guaranteeing diffusion
Knot, and use KOH, NH3.H2O and H2O2Solution carries out pattern modification to black silicon flannelette, further improves flannelette and hole inner wall
Micro-structure forms more smooth inner wall, further improves the black serious surface recombination of silicon flannelette, so that the present invention mentions
The silion cell that the silicon wafer of the making herbs into wool of confession is further prepared has good electric property.
It is clearly and completely described below in conjunction with the technical solution of the embodiment of the present invention, it is clear that described implementation
Example is only a part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, this field is common
Technical staff's every other embodiment obtained without making creative work belongs to the model that the present invention protects
It encloses.
Additive A involved in the embodiment of the present application, B, C, D are to receive prosperous production.
Embodiment 1
1) sink silver: depositing one layer of silver nano-grain in silicon chip surface, it is specific the preparation method comprises the following steps: by silicon wafer merging hydrofluoric acid and
In the mixed solution of additive B composition, wherein in the mixed solution, solvent is water, and the mass percent concentration of HF is 0.88%,
The mass percent concentration of additive B is 0.8%;25 DEG C of reaction temperature, reaction time 1min-3min, obtain deposition silver nanoparticle
The silicon wafer of particle;
(2) silicon wafer for having deposited silver nano-grain borehole: is subjected to borehole.Specifically the preparation method comprises the following steps: being received silver has been deposited
In the mixed solution that silicon wafer merging HF, hydrogen peroxide, addition of C and the additive D of rice grain are formed, wherein the mixed solution
In, water is solvent, and the mass percent concentration of HF is 4.7%, H2O2Mass percent concentration be 9.6%, the matter of addition of C
Measuring percent concentration is 0.5%, and the mass percent concentration of additive D is 0.15%, 30-40 DEG C of temperature, reaction time 2min-
6min;Obtain the silicon wafer of borehole;
(3) first step reaming: by after borehole silicon wafer merging nitric acid and hydrofluoric acid mixed solution in (water is solvent) into
Row reaction, wherein the mass percent concentration of nitric acid is 37.4% in the mixed solution, and the mass percent concentration of hydrofluoric acid is
3.9%, reaction temperature is 10 DEG C, and reaction time 60s obtains the silicon wafer of first step reaming;
(4) second step reaming: the mixing that will complete the silicon wafer merging hydrogen peroxide and ammonium fluoride composition of first step reaming is water-soluble
It is reacted in liquid, wherein H2O2Mass percent concentration is 9%, NH4F mass percent concentration is 0.8%, temperature 11
DEG C, reaction time 220s obtains the silicon wafer of second step reaming
(5) alkali cleaning: the silicon wafer of second step reaming is placed in, and in terms of mass percent concentration, group becomes (2.7%) KOH+
(1.0%) NH3.H20+ (1.8%) H2O2+ 94.5%H2In the mixed solution of O, temperature is 40 DEG C, time 2min-4min, to silicon
Piece flannelette carries out modification suede, obtains the silicon wafer of making herbs into wool.
Electron microscope analysis, the result is shown in Figure 1 and Fig. 2, Fig. 1 are carried out for the preparation of the embodiment of the present invention 1 to the silicon wafer of obtained making herbs into wool
Making herbs into wool silicon wafer 15000 times of scanning electron microscope (SEM) photographs;Fig. 2 is 20000 times of fields of the silicon wafer of making herbs into wool prepared by the embodiment of the present invention 1
Emit scanning electron microscope (SEM) photograph;It can be seen from the figure that hole diameter size is 850nm-1000nm, hole depth 500nm-650nm, hole
Interior micro-structure removal is clean, the smooth flannelette of inner wall smooth.
Silion cell is further prepared according to common process well known in the art in the silicon wafer of obtained making herbs into wool, and to it
Performance is tested, and the results are shown in Table 1, table 1 is the silion cell of the silicon wafer preparation for the making herbs into wool that the embodiment of the present invention and comparative example provide
The performance test results.
Table 1
As can be seen from the table, the silion cell open-circuit voltage and filling that the silicon wafer of making herbs into wool provided by the invention is further prepared
The factor is improved, and illustrates that surface micro-structure provided by the invention is reduced, advantageously reduces surface recombination, and then improves silicon electricity
The electric property in pond.
Comparative example 1
1) sink silver: depositing one layer of silver nano-grain in silicon chip surface, it is specific the preparation method comprises the following steps: by silicon wafer merging hydrofluoric acid and
In the mixed solution of additive B composition, wherein in the mixed solution, solvent is water, and the mass percent concentration of HF is 0.88%,
The mass percent concentration of additive B is 0.8%;25 DEG C of reaction temperature, reaction time 1min-3min, obtain deposition silver nanoparticle
The silicon wafer of particle;
(2) silicon wafer for having deposited silver nano-grain borehole: is subjected to borehole.Specifically the preparation method comprises the following steps: being received silver has been deposited
In the mixed solution that silicon wafer merging HF, hydrogen peroxide, addition of C and the additive D of rice grain are formed, wherein the mixed solution
In, water is solvent, and the mass percent concentration of HF is 4.7%, H2O2Mass percent concentration be 9.6%, the matter of addition of C
Measuring percent concentration is 0.5%, and the mass percent concentration of additive D is 0.15%, 30-40 DEG C of temperature, reaction time 2min-
6min;Obtain the silicon wafer of borehole;
(3) first step reaming: by after borehole silicon wafer merging nitric acid and hydrofluoric acid mixed solution in (water is solvent) into
Row reaction, wherein the mass percent concentration of nitric acid is 37.4% in the mixed solution, and the mass percent concentration of hydrofluoric acid is
3.9%, reaction temperature is 10 DEG C, and reaction time 60s obtains the silicon wafer of first step reaming;
(4) second step reaming: the mixing that will complete the silicon wafer merging hydrogen peroxide and ammonium fluoride composition of first step reaming is water-soluble
It is reacted in liquid, wherein H2O2Mass percent concentration is 6%, NH4F mass percent concentration is 1.2%, temperature 11
DEG C, reaction time 220s obtains the silicon wafer of second step reaming
(5) alkali cleaning: the silicon wafer of second step reaming is placed in terms of mass percent concentration, and group becomes (2.7%) KOH+
(1.0%) NH3.H2O+ (1.8%) H2O2+ 94.5%H2In the mixed solution of O, temperature is 40 DEG C, time 2min-4min, to silicon
Piece flannelette carries out modification suede, obtains the silicon wafer of making herbs into wool.
Electron microscope analysis is carried out to the silicon wafer of obtained making herbs into wool, as a result sees that Fig. 3 and Fig. 4, Fig. 3 are comparative example 1 of the present invention preparation
Making herbs into wool silicon wafer 15000 times of scanning electron microscope (SEM) photographs;Fig. 4 is 20000 times of fields of the silicon wafer of the making herbs into wool of comparative example 1 of the present invention preparation
Emit scanning electron microscope (SEM) photograph;It can be seen from the figure that concentration has a significant impact to the reaming of silicon wafer in second step reaming, in comparative example
Meeting is easy to cause reaming further expansion so that silicon slice corrosion rate is excessive under the conditions of 1 reaming provided, be easy to cause perforation,
Folded hole, and then the efficiency of obtained silion cell is influenced, because the silicon wafer of the step making herbs into wool is unfavorable for passivation and the absorption of light, and then drop
The efficiency of low cell piece.
Silion cell is further prepared according to method similarly to Example 1 in the silicon wafer of obtained making herbs into wool, and to it
Performance is tested, and the results are shown in Table 1, table 1 is the silion cell of the silicon wafer preparation for the making herbs into wool that the embodiment of the present invention and comparative example provide
The performance test results.
Comparative example 2
1) sink silver: depositing one layer of silver nano-grain in silicon chip surface, it is specific the preparation method comprises the following steps: by silicon wafer merging hydrofluoric acid and
In the mixed solution of additive B composition, wherein in the mixed solution, solvent is water, and the mass percent concentration of HF is 0.88%,
The mass percent concentration of additive B is 0.8%;25 DEG C of reaction temperature, reaction time 1min-3min, obtain deposition silver nanoparticle
The silicon wafer of particle;
(2) borehole: the silicon wafer for having deposited silver nano-grain is subjected to borehole.Specifically the preparation method comprises the following steps: being received silver has been deposited
In the mixed solution that silicon wafer merging HF, hydrogen peroxide, addition of C and the additive D of rice grain are formed, wherein the mixed solution
In, water is solvent, and the mass percent concentration of HF is 4.7%, H2O2Mass percent concentration be 9.6%, the matter of addition of C
Measuring percent concentration is 0.5%, and the mass percent concentration of additive D is 0.15%, 30-40 DEG C of temperature, reaction time 2min-
6min;Obtain the silicon wafer of borehole;
(3) one step reamings: (water is solvent) in the mixed solution of silicon wafer merging nitric acid and hydrofluoric acid after borehole is carried out
Reaction, wherein the mass percent concentration of nitric acid is 28.6% in the mixed solution, and the mass percent concentration of hydrofluoric acid is
3.0%, reaction temperature is 10 DEG C, and the reaction time 115 obtains the silicon wafer of first step reaming;
(4) alkali cleaning: the silicon wafer of a step reaming is placed in, and in terms of mass percent concentration, group becomes (2.7%) KOH+
(1.0%) NH3.H20+ (1.8%) H2O2+ 94.5%H2In the mixed solution of O, temperature is 40 DEG C, time 2min-4min, to silicon
Piece flannelette carries out modification suede, obtains the silicon wafer of making herbs into wool.Electron microscope analysis is carried out to the silicon wafer of obtained making herbs into wool, as a result sees Fig. 5 and figure
15000 times of scanning electron microscope (SEM) photographs of the silicon wafer of 6, Fig. 5 making herbs into wool prepared for comparative example 2 of the present invention;Fig. 6 is comparative example 2 of the present invention system
20000 times of field emission scanning electron microscope figures of the silicon wafer of standby making herbs into wool;It can be seen from the figure that its hole size is uneven.
Silion cell is further prepared according to method similarly to Example 1 in the silicon wafer of obtained making herbs into wool, and to it
Performance is tested, and the results are shown in Table 1, table 1 is the silion cell of the silicon wafer preparation for the making herbs into wool that the embodiment of the present invention and comparative example provide
The performance test results.
The above description of the embodiment is only used to help understand the method for the present invention and its core ideas.It should be pointed out that pair
For those skilled in the art, without departing from the principle of the present invention, the present invention can also be carried out
Some improvements and modifications, these improvements and modifications also fall within the scope of protection of the claims of the present invention.