CN117711918B - Low-temperature polysilicon film and preparation method thereof - Google Patents
Low-temperature polysilicon film and preparation method thereof Download PDFInfo
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- 229910021420 polycrystalline silicon Inorganic materials 0.000 title claims abstract description 65
- 238000002360 preparation method Methods 0.000 title claims abstract description 47
- 229920005591 polysilicon Polymers 0.000 title claims description 44
- 239000000758 substrate Substances 0.000 claims abstract description 64
- 238000000034 method Methods 0.000 claims abstract description 55
- 239000002131 composite material Substances 0.000 claims abstract description 53
- 239000004005 microsphere Substances 0.000 claims abstract description 50
- JUZTWRXHHZRLED-UHFFFAOYSA-N [Si].[Cu].[Cu].[Cu].[Cu].[Cu] Chemical compound [Si].[Cu].[Cu].[Cu].[Cu].[Cu] JUZTWRXHHZRLED-UHFFFAOYSA-N 0.000 claims abstract description 40
- 229910021417 amorphous silicon Inorganic materials 0.000 claims abstract description 40
- 229910021360 copper silicide Inorganic materials 0.000 claims abstract description 40
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims abstract description 37
- 239000007788 liquid Substances 0.000 claims abstract description 36
- 238000011282 treatment Methods 0.000 claims abstract description 26
- 239000011248 coating agent Substances 0.000 claims abstract description 19
- 238000000576 coating method Methods 0.000 claims abstract description 19
- 239000011521 glass Substances 0.000 claims abstract description 19
- 238000001035 drying Methods 0.000 claims abstract description 16
- 238000002156 mixing Methods 0.000 claims abstract description 12
- 238000005229 chemical vapour deposition Methods 0.000 claims abstract description 11
- 238000000151 deposition Methods 0.000 claims abstract description 11
- 238000013532 laser treatment Methods 0.000 claims abstract description 11
- 238000004140 cleaning Methods 0.000 claims abstract description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 60
- 239000010408 film Substances 0.000 claims description 47
- 238000003756 stirring Methods 0.000 claims description 45
- 229910021591 Copper(I) chloride Inorganic materials 0.000 claims description 36
- OXBLHERUFWYNTN-UHFFFAOYSA-M copper(I) chloride Chemical compound [Cu]Cl OXBLHERUFWYNTN-UHFFFAOYSA-M 0.000 claims description 36
- 229940045803 cuprous chloride Drugs 0.000 claims description 36
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 claims description 35
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 31
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 31
- 238000006243 chemical reaction Methods 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 18
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 17
- 239000001257 hydrogen Substances 0.000 claims description 16
- 229910052739 hydrogen Inorganic materials 0.000 claims description 16
- 239000003513 alkali Substances 0.000 claims description 15
- 239000011863 silicon-based powder Substances 0.000 claims description 15
- 238000005303 weighing Methods 0.000 claims description 15
- 238000005224 laser annealing Methods 0.000 claims description 14
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 11
- 238000005245 sintering Methods 0.000 claims description 11
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 10
- 238000006356 dehydrogenation reaction Methods 0.000 claims description 10
- 239000002243 precursor Substances 0.000 claims description 10
- 150000002431 hydrogen Chemical class 0.000 claims description 9
- 238000004321 preservation Methods 0.000 claims description 9
- 239000010409 thin film Substances 0.000 claims description 7
- 239000007789 gas Substances 0.000 claims description 6
- 239000002244 precipitate Substances 0.000 claims description 6
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 claims description 5
- 239000008367 deionised water Substances 0.000 claims description 5
- 229910021641 deionized water Inorganic materials 0.000 claims description 5
- 230000008021 deposition Effects 0.000 claims description 5
- 238000001914 filtration Methods 0.000 claims description 5
- 239000011261 inert gas Substances 0.000 claims description 5
- 230000007935 neutral effect Effects 0.000 claims description 5
- 229910000077 silane Inorganic materials 0.000 claims description 5
- 239000007787 solid Substances 0.000 claims description 5
- 238000005406 washing Methods 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 239000004065 semiconductor Substances 0.000 abstract description 4
- 230000007547 defect Effects 0.000 abstract description 2
- 239000000463 material Substances 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000010923 batch production Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910021419 crystalline silicon Inorganic materials 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000005338 heat storage Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 239000002120 nanofilm Substances 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
Abstract
The invention relates to the field of semiconductors, in particular to a preparation method of a low-temperature polycrystalline silicon film, which comprises the following steps: step 1, preparing a glass substrate as a substrate, cleaning the surface of the substrate, and drying the substrate in an oven; step 2, preparing copper silicide porous microspheres, and mixing the copper silicide porous microspheres with silica sol to form a composite liquid; step 3, coating a composite liquid on the substrate, and forming a composite layer after treatment at a certain temperature; step 4, depositing an amorphous silicon layer on the composite layer by a chemical vapor deposition method; and 5, after preheating the substrate, carrying out low-temperature laser treatment on the amorphous silicon layer to obtain the polycrystalline silicon film. According to the invention, the method in the prior art is improved, the polycrystalline silicon film is prepared under the condition of low temperature, the preparation process is simple and convenient, the time for forming polycrystalline silicon is short, and the method is suitable for large-scale popularization and use. The polycrystalline silicon film prepared by the method has larger grain size, fewer defects and regular arrangement, and the electron mobility of the polycrystalline silicon film is larger.
Description
Technical Field
The invention relates to the field of semiconductors, in particular to a low-temperature polycrystalline silicon film and a preparation method thereof.
Background
The polysilicon film has the electrical characteristics of crystalline silicon, and has the advantages of low cost, simple equipment, large-area preparation and the like of the amorphous silicon film, so that the polysilicon film has wide application in the fields of integrated circuits and liquid crystal displays, and has been widely researched in the aspect of solar photoelectric conversion, and great hopes are given. Polysilicon thin films find wide application in some semiconductor devices and integrated circuits. Because the production cost of polysilicon is low, the efficiency and stability are good, the photoelectric conversion efficiency is high, and the research of polysilicon films is of great interest. Polysilicon films are now widely used in the fabrication of a variety of microelectronic devices, ranging in use from gate materials and interconnect leads to insulating isolation, passivation, solar cells, various photovoltaic devices, and the like.
Polysilicon thin films are widely used in semiconductor devices and integrated circuits, and polysilicon materials can be used to fabricate gate materials for MOS devices, sacrificial layer materials, solar cells and various optoelectronic devices. Along with the rapid development of MEMS (micro electro mechanical system) technology, the polysilicon thin film is widely applied to piezoresistive pressure sensors, and meanwhile, the piezoresistive properties of the polysilicon nano film are more superior to those of common polysilicon. And thus have received attention from a large number of researchers.
Compared with a monocrystalline silicon film, the polycrystalline silicon film is more compatible with an IC process, has good high-temperature characteristics, and has no p-n junction isolation problem in a high-temperature device. The polycrystalline silicon film can also be used for manufacturing a sacrificial layer material, is easy to micromachine, has a strain coefficient of about two thirds of that of monocrystalline silicon, and has a strain coefficient higher than that of monocrystalline silicon material when being heavily doped.
At present, the preparation of the polysilicon film process mainly uses a high-temperature process, the process temperature is higher than 600 ℃, the polysilicon film can be prepared by thermally decomposing process gas in a high-temperature quartz tube, and the preparation process is simple; however, the high temperature process firstly has higher requirements on equipment, and secondly has more heat loss in the polysilicon during the high temperature preparation process, thereby reducing the conversion efficiency of the solar cell. Therefore, in recent years, low-temperature processes are gradually developed, the processing temperature of the low-temperature processes is generally lower than 600 ℃, glass with lower cost can be used as a substrate material, and the low-temperature processes are suitable for batch production, but the quality of polysilicon films produced by the low-temperature processes is uneven at present.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a low-temperature polysilicon film and a preparation method thereof.
The aim of the invention is realized by adopting the following technical scheme:
the preparation method of the low-temperature polysilicon film comprises the following steps:
step 1, preparing a glass substrate as a substrate, cleaning the surface of the substrate, and drying the substrate in an oven;
step 2, preparing copper silicide porous microspheres, and mixing the copper silicide porous microspheres with silica sol to form a composite liquid;
step 3, coating a composite liquid on the substrate, and forming a composite layer after treatment at a certain temperature;
step 4, depositing an amorphous silicon layer on the composite layer by a chemical vapor deposition method;
and 5, after preheating the substrate, carrying out low-temperature laser treatment on the amorphous silicon layer to obtain the polycrystalline silicon film.
Preferably, in the step 1, the glass substrate has a softening temperature higher than 600 ℃ and a thickness of 500-1000 μm.
Preferably, in the step 2, the preparation method of the copper silicide porous microsphere comprises the following steps:
s1, weighing ethyl orthosilicate, adding the ethyl orthosilicate into absolute ethyl alcohol, and fully and uniformly stirring to form an ethyl orthosilicate solution;
s2, weighing cuprous chloride, adding the cuprous chloride into ammonia water, and stirring at 40-50 ℃ until the cuprous chloride is completely dissolved to obtain a cuprous chloride solution;
s3, dropwise adding the tetraethoxysilane solution into the continuously stirred cuprous chloride solution at room temperature, wherein the stirring speed is 800-1000r/min, and after all the tetraethoxysilane solution is added, the stirring speed is reduced to 400-500r/min, and continuously stirring for 8-12h at room temperature to obtain a mixed reaction solution;
s4, centrifugally filtering the mixed reaction solution obtained in the step S3, collecting solid precipitate, washing to be neutral by using deionized water, and drying in an oven to obtain a microsphere precursor;
s5, heating the microsphere precursor to 800-1000 ℃ under the protection of inert gas, sintering for 3-5h, then introducing hydrogen, performing heat preservation and sintering for 1h again, and cooling to room temperature along with a furnace to obtain the copper silicide porous microspheres.
Preferably, in the S1, the mass ratio of the tetraethoxysilane to the absolute ethyl alcohol is 1:1.4-1.8.
Preferably, in the step S2, the mass fraction of the ammonia water is 10% -20%, and the mass ratio of the cuprous chloride to the ammonia water is 1:6-10.
Preferably, in the step S3, the mass ratio of the tetraethoxysilane solution to the cuprous chloride solution is 1:2.1-4.2.
Preferably, in the step S4, the temperature of the oven is 100-120 ℃ and the drying time is 4-8h.
Preferably, in S5, the hydrogen gas is introduced in an amount of 10% -15% of the total gas volume.
Preferably, in the step 2, the preparation method of the silica sol comprises the following steps:
weighing ammonia water and sodium hydroxide solution, mixing into a reaction bottle, heating to 50-60 ℃, uniformly stirring, adding the weighed silicon powder, keeping the temperature, stirring and reacting for 2 hours, continuously dripping alkali liquor, continuously stirring and reacting for 4-6 hours after dripping, and cooling to room temperature to obtain silica sol;
more preferably, in the preparation process of the silica sol, the mass concentration of the ammonia water is 10% -20%, the concentration of the sodium hydroxide solution is 0.1mol/L, and the mass ratio of the silicon powder to the ammonia water to the sodium hydroxide solution is 1:0.1-0.3:5-10.
More preferably, in the preparation process of the silica sol, the alkali liquor is sodium hydroxide solution with the concentration of 0.5mol/L, the dripping time is controlled to be 1h, and the dripping mass of the alkali liquor is 2-4 times that of the silicon powder.
Preferably, in the step 2, the preparation method of the composite liquid comprises the following steps: adding the copper silicide porous microspheres into the silica sol, and fully stirring for 8-12 hours at room temperature to obtain a composite solution; wherein the mass ratio of the copper silicide porous microsphere to the silica sol is 1:4-8.
Preferably, in the step 3, the composite liquid is coated for a plurality of times, the thickness of the single coating is 20-50 μm, and the number of times of the plurality of times of coating is 2-5 times.
Preferably, in the step 3, the certain temperature means that after the temperature is heated to be completely dried at 80 ℃, the temperature is raised to 250-300 ℃ and the heat preservation treatment is carried out for 2-5 hours.
Preferably, in the step 4, the thickness of the amorphous silicon layer formed by the chemical vapor deposition method is 250-350nm; during the deposition, the temperature of the substrate is 220-250 ℃, and the volume flow ratio of silane (SiH 4) to hydrogen (H2) is 1:8.
Preferably, in the step 5, the temperature of the substrate preheating treatment is 200-300 ℃.
Preferably, in the step 5, the low-temperature laser treatment is dehydrogenation treatment first and then excimer laser annealing treatment; dehydrogenation is to reduce the hydrogen content in the amorphous silicon layer to within 3%The method comprises the steps of carrying out a first treatment on the surface of the The laser pulse frequency of excimer laser annealing is 450-550Hz, the light spot width is 100-300 μm, and the laser energy density is 350-450mJ/cm 2 The scanning speed is 5-6mm/s.
The beneficial effects of the invention are as follows:
1. the method is improved in the prior art, the polycrystalline silicon film is prepared under the condition of low temperature, the preparation process of the method is simple and convenient, the time of forming polycrystalline silicon by crystallizing amorphous silicon is short, and the method is suitable for large-scale popularization and use. The polycrystalline silicon film prepared by the method has larger grain size, fewer defects and regular arrangement, and the electron mobility of the polycrystalline silicon film is larger.
2. In the prior art, when the low-temperature process is adopted to prepare the polysilicon, a laser annealing method is mainly adopted to form the polysilicon film, however, in the laser annealing process, the amorphous silicon layer can be gradually melted from top to bottom, so that the control of the laser intensity is important, if the intensity is weaker, the amorphous silicon on the lower layer can not be completely melted, and if the intensity is too strong, the generated film can generate holes. The preparation process of the invention considers the problems and adopts two modes to match for solving, firstly, the substrate is preheated in the crystallization process of the amorphous silicon, and secondly, a composite layer is arranged between the substrate and the amorphous silicon. The method combining the two modes can lead the amorphous silicon to have better grain growth in the process of crystallizing the amorphous silicon into the polycrystalline silicon, thereby obtaining larger and more uniform grains.
3. In the prior art, a substrate preheating mode is adopted to enhance the growth of grains, but the conventional glass has poor heat conductivity, and even the thermal field is insufficient after preheating, the uneven growth of grains at the bottom of amorphous silicon is easily caused; in addition, the common glass substrate is not heat-resistant, and impurities are easy to migrate into amorphous silicon after being heated, so that the growth of crystal grains is affected. The invention is provided with a composite layer, the main component of the composite layer is the silicon dioxide coated copper silicide porous microsphere, and the composite layer not only has certain high temperature bearing property, but also has certain heat storage capacity, thereby enhancing the thermal field control force, being capable of absorbing heat during preheating, continuously and uniformly transmitting the heat to the lower layer of amorphous silicon after the preheating is finished, ensuring that the lower layer is heated sufficiently and uniformly, and being beneficial to the formation of large-grain-size grains.
4. The composite layer prepared by the method is a film structure formed by the silica coated copper silicide porous microspheres under a certain condition, and the preparation process mainly comprises the steps of preparing the copper silicide porous microspheres by using a copper source and a silicon source, and then compositing the copper silicide porous microspheres with the prepared silica sol to enable silica particles in the silica sol to be adsorbed and coated inside and on the surfaces of the porous microspheres. The process for preparing the copper silicide porous microspheres comprises the steps of mixing silicon liquid formed by tetraethoxysilane and absolute ethyl alcohol with copper liquid formed by cuprous chloride and ammonia water, and sintering formed microsphere precipitates to obtain the copper silicide porous microspheres.
Detailed Description
The technical scheme of the invention is described below through specific examples. It is to be understood that the reference to one or more method steps of the invention does not exclude the presence of other method steps before or after the combination step or that other method steps may be interposed between these explicitly mentioned steps; it should also be understood that these examples are illustrative of the present invention and are not intended to limit the scope of the present invention. Moreover, unless otherwise indicated, the numbering of the method steps is merely a convenient tool for identifying the method steps and is not intended to limit the order of arrangement of the method steps or to limit the scope of the invention in which the invention may be practiced, as such changes or modifications in their relative relationships may be regarded as within the scope of the invention without substantial modification to the technical matter.
In the prior art, when the low-temperature process is adopted to prepare the polysilicon, a laser annealing method is mainly adopted to form the polysilicon film, in the laser annealing process, after the amorphous silicon is irradiated by laser, the amorphous silicon begins to melt after the surface temperature reaches the melting point, and with the increase of laser energy, the amorphous silicon layer can be gradually melted from top to bottom, and after the laser is closed, the melted amorphous silicon layer can be gradually cooled and recrystallized to obtain the polysilicon film. However, in the conventional laser annealing operation, after the laser is irradiated from the upper surface of the amorphous silicon layer, the amorphous silicon layer is gradually melted from top to bottom, and in this process, if the irradiation intensity is weak, the amorphous silicon of the lower layer cannot be completely melted, and if the irradiation intensity is too strong, the generated film generates holes, so that the intensity requirement on the laser is very high.
In order to better understand the above technical solution, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the invention are shown, it should be understood that the invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The invention is further described with reference to the following examples.
Example 1
The preparation method of the low-temperature polysilicon film comprises the following steps:
step 1, preparing a glass substrate as a substrate, cleaning the surface of the substrate, and drying the substrate in an oven; wherein the softening temperature of the glass substrate is higher than 600 ℃ and the thickness of the glass substrate is 800 mu m.
Step 2, preparing copper silicide porous microspheres, and mixing the copper silicide porous microspheres with silica sol to form a composite liquid, wherein the preparation method of the composite liquid comprises the following steps: adding the copper silicide porous microspheres into the silica sol, and fully stirring for 10 hours at room temperature to obtain a composite liquid; wherein the mass ratio of the copper silicide porous microspheres to the silica sol is 1:6;
step 3, coating a composite liquid on the substrate, wherein the composite liquid is coated for a plurality of times, the thickness of single coating is 30 mu m, the number of times of the plurality of times of coating is 3, heating the composite liquid to be completely dried at 80 ℃ after the coating of the composite liquid, heating to 300 ℃, and carrying out heat preservation treatment for 3 hours to form a composite layer;
step 4, depositing an amorphous silicon layer on the composite layer by a chemical vapor deposition method, wherein the thickness of the amorphous silicon layer formed by the chemical vapor deposition method is 300nm; during deposition, the temperature of the substrate was 250 ℃, silane (SiH 4 ) With hydrogen (H) 2 ) The volume flow ratio of (1):8；
step 5, after the substrate preheating treatment, the temperature of the substrate preheating treatment is 250 ℃, then the amorphous silicon layer is subjected to low-temperature laser treatment, the low-temperature laser treatment is dehydrogenation treatment firstly, and then excimer laser annealing treatment is carried out; dehydrogenation is to reduce the hydrogen content in the amorphous silicon layer to within 3%; the laser pulse frequency of excimer laser annealing is 500Hz, the light spot width is 200 μm, and the laser energy density is 400mJ/cm 2 The scanning speed is 5mm/s, and the polycrystalline silicon film is obtained.
In the step 2, the preparation method of the copper silicide porous microsphere comprises the following steps:
s1, weighing ethyl orthosilicate, adding the ethyl orthosilicate into absolute ethyl alcohol, and fully and uniformly stirring to form an ethyl orthosilicate solution; wherein the mass ratio of the tetraethoxysilane to the absolute ethyl alcohol is 1:1.6.
S2, weighing cuprous chloride, adding the cuprous chloride into ammonia water, and stirring at 45 ℃ until the cuprous chloride is completely dissolved to obtain a cuprous chloride solution; wherein the mass fraction of the ammonia water is 15%, and the mass ratio of the cuprous chloride to the ammonia water is 1:8.
S3, dropwise adding the tetraethoxysilane solution into the continuously stirred cuprous chloride solution at room temperature, wherein the stirring speed is 1000r/min, and after all the tetraethoxysilane solution is added, the stirring speed is reduced to 450r/min, and continuously stirring for 10 hours at room temperature to obtain a mixed reaction solution; wherein the mass ratio of the ethyl orthosilicate solution to the cuprous chloride solution is 1:3.2.
S4, centrifugally filtering the mixed reaction solution obtained in the step S3, collecting solid precipitate, washing to be neutral by using deionized water, drying in a drying oven at 120 ℃ for 6 hours to obtain microsphere precursors;
and S5, heating the microsphere precursor to 1000 ℃ under the protection of inert gas, sintering for 4 hours, then introducing hydrogen with the introduced amount of 12% of the total gas volume, performing heat preservation and sintering for 1 hour again, and cooling to room temperature along with a furnace to obtain the copper silicide porous microspheres.
In the step 2, the preparation method of the silica sol comprises the following steps:
weighing ammonia water and sodium hydroxide solution, mixing into a reaction bottle, heating to 55 ℃, uniformly stirring, adding the weighed silicon powder, keeping the temperature, stirring and reacting for 2 hours, continuously dripping alkali liquor, continuously stirring and reacting for 5 hours after dripping, and cooling to room temperature to obtain silica sol;
wherein the mass concentration of the ammonia water is 15%, the concentration of the sodium hydroxide solution is 0.1mol/L, and the mass ratio of the silicon powder to the ammonia water to the sodium hydroxide solution is 1:0.2:8; the alkali liquor is sodium hydroxide solution with the concentration of 0.5mol/L, the dripping time is controlled to be 1h, and the dripping mass of the alkali liquor is 3 times of the mass of the silicon powder.
Example 2
The preparation method of the low-temperature polysilicon film comprises the following steps:
step 1, preparing a glass substrate as a substrate, cleaning the surface of the substrate, and drying the substrate in an oven; wherein the softening temperature of the glass substrate is higher than 600 ℃ and the thickness of the glass substrate is 500 mu m.
Step 2, preparing copper silicide porous microspheres, and mixing the copper silicide porous microspheres with silica sol to form a composite liquid, wherein the preparation method of the composite liquid comprises the following steps: adding the copper silicide porous microspheres into the silica sol, and fully stirring for 8 hours at room temperature to obtain a composite liquid; wherein the mass ratio of the copper silicide porous microsphere to the silica sol is 1:4.
Step 3, coating a composite liquid on the substrate, wherein the composite liquid is coated for a plurality of times, the thickness of single coating is 20 mu m, the number of times of the plurality of times of coating is 2, heating the composite liquid to be completely dried at 80 ℃ after the coating of the composite liquid, heating to 250 ℃, and carrying out heat preservation treatment for 2 hours to form a composite layer;
step 4, depositing an amorphous silicon layer on the composite layer by a chemical vapor deposition method, wherein the thickness of the amorphous silicon layer formed by the chemical vapor deposition method is 250nm; during deposition, the temperature of the substrate was 220 ℃, silane (SiH 4 ) With hydrogen (H) 2 ) The volume flow ratio of (2) is 1:8;
step 5, after the substrate preheating treatment, the temperature of the substrate preheating treatment is 200 ℃, then the amorphous silicon layer is subjected to low-temperature laser treatment, the low-temperature laser treatment is dehydrogenation treatment firstly, and then excimer laser annealing treatment is carried out; dehydrogenation is to reduce the hydrogen content in the amorphous silicon layer to within 3%; the laser pulse frequency of the excimer laser annealing is 450Hz, the light spot width is 100 μm,the laser energy density is 350mJ/cm 2 The scanning speed is 5mm/s, and the polycrystalline silicon film is obtained.
In the step 2, the preparation method of the copper silicide porous microsphere comprises the following steps:
s1, weighing ethyl orthosilicate, adding the ethyl orthosilicate into absolute ethyl alcohol, and fully and uniformly stirring to form an ethyl orthosilicate solution; wherein the mass ratio of the tetraethoxysilane to the absolute ethyl alcohol is 1:1.4.
S2, weighing cuprous chloride, adding the cuprous chloride into ammonia water, and stirring at 40 ℃ until the cuprous chloride is completely dissolved to obtain a cuprous chloride solution; wherein the mass fraction of the ammonia water is 10%, and the mass ratio of the cuprous chloride to the ammonia water is 1:6.
S3, dropwise adding the tetraethoxysilane solution into the continuously stirred cuprous chloride solution at room temperature, wherein the stirring speed is 800r/min, and after all the tetraethoxysilane solution is added, the stirring speed is reduced to 400r/min, and continuously stirring for 8 hours at room temperature to obtain a mixed reaction solution; wherein the mass ratio of the ethyl orthosilicate solution to the cuprous chloride solution is 1:2.1.
S4, centrifugally filtering the mixed reaction solution obtained in the step S3, collecting solid precipitate, washing to be neutral by using deionized water, drying in a drying oven at 100 ℃ for 4 hours to obtain microsphere precursors;
and S5, heating the microsphere precursor to 800 ℃ under the protection of inert gas, sintering for 3 hours, then introducing hydrogen with the introduced amount of 10% of the total gas volume, performing heat preservation and sintering for 1 hour again, and cooling to room temperature along with a furnace to obtain the copper silicide porous microspheres.
In the step 2, the preparation method of the silica sol comprises the following steps:
weighing ammonia water and sodium hydroxide solution, mixing into a reaction bottle, heating to 50 ℃, uniformly stirring, adding the weighed silicon powder, keeping the temperature, stirring and reacting for 2 hours, continuously dripping alkali liquor, continuously stirring and reacting for 4 hours after dripping, and cooling to room temperature to obtain silica sol;
in the preparation process of the silica sol, the mass concentration of ammonia water is 10%, the concentration of sodium hydroxide solution is 0.1mol/L, and the mass ratio of silicon powder to ammonia water to sodium hydroxide solution is 1:0.1:5; in the preparation process of the silica sol, the alkali liquor is sodium hydroxide solution with the concentration of 0.5mol/L, the dripping time is controlled to be 1h, and the dripping quality of the alkali liquor is 2 times that of the silicon powder.
Example 3
The preparation method of the low-temperature polysilicon film comprises the following steps:
step 1, preparing a glass substrate as a substrate, cleaning the surface of the substrate, and drying the substrate in an oven; wherein the softening temperature of the glass substrate is higher than 600 ℃ and the thickness of the glass substrate is 1000 mu m.
Step 2, preparing copper silicide porous microspheres, and mixing the copper silicide porous microspheres with silica sol to form a composite liquid, wherein the preparation method of the composite liquid comprises the following steps: adding the copper silicide porous microspheres into the silica sol, and fully stirring for 12 hours at room temperature to obtain a composite liquid; wherein the mass ratio of the copper silicide porous microsphere to the silica sol is 1:8.
Step 3, coating a composite liquid on the substrate, wherein the composite liquid is coated for a plurality of times, the thickness of single coating is 50 mu m, the number of times of the plurality of times of coating is 5, heating the composite liquid to be completely dried at 80 ℃ after the coating of the composite liquid, heating to 300 ℃, and carrying out heat preservation treatment for 5 hours to form a composite layer;
step 4, depositing an amorphous silicon layer on the composite layer by a chemical vapor deposition method, wherein the thickness of the amorphous silicon layer formed by the chemical vapor deposition method is 350nm; during deposition, the temperature of the substrate was 250 ℃, silane (SiH 4 ) With hydrogen (H) 2 ) The volume flow ratio of (2) is 1:8;
step 5, after the substrate preheating treatment, the temperature of the substrate preheating treatment is 300 ℃, then the amorphous silicon layer is subjected to low-temperature laser treatment, the low-temperature laser treatment is dehydrogenation treatment firstly, and then excimer laser annealing treatment is carried out; dehydrogenation is to reduce the hydrogen content in the amorphous silicon layer to within 3%; the laser pulse frequency of excimer laser annealing is 550Hz, the light spot width is 300 mu m, and the laser energy density is 450mJ/cm 2 The scanning speed is 6mm/s, and the polycrystalline silicon film is obtained.
In the step 2, the preparation method of the copper silicide porous microsphere comprises the following steps:
s1, weighing ethyl orthosilicate, adding the ethyl orthosilicate into absolute ethyl alcohol, and fully and uniformly stirring to form an ethyl orthosilicate solution; wherein the mass ratio of the tetraethoxysilane to the absolute ethyl alcohol is 1:1.8.
S2, weighing cuprous chloride, adding the cuprous chloride into ammonia water, and stirring at 50 ℃ until the cuprous chloride is completely dissolved to obtain a cuprous chloride solution; wherein the mass fraction of the ammonia water is 20%, and the mass ratio of the cuprous chloride to the ammonia water is 1:10.
S3, dropwise adding the tetraethoxysilane solution into the continuously stirred cuprous chloride solution at room temperature, wherein the stirring speed is 1000r/min, and after all the tetraethoxysilane solution is added, the stirring speed is reduced to 500r/min, and continuously stirring for 12 hours at room temperature to obtain a mixed reaction solution; wherein the mass ratio of the ethyl orthosilicate solution to the cuprous chloride solution is 1:4.2.
S4, centrifugally filtering the mixed reaction solution obtained in the step S3, collecting solid precipitate, washing to be neutral by using deionized water, drying in a drying oven at 120 ℃ for 8 hours to obtain microsphere precursors;
and S5, heating the microsphere precursor to 1000 ℃ under the protection of inert gas, sintering for 5 hours, then introducing hydrogen, wherein the introduced amount of the hydrogen is 15% of the total gas volume, performing heat preservation and sintering for 1 hour again, and cooling to room temperature along with a furnace to obtain the copper silicide porous microspheres.
In the step 2, the preparation method of the silica sol comprises the following steps:
weighing ammonia water and sodium hydroxide solution, mixing into a reaction bottle, heating to 60 ℃, uniformly stirring, adding the weighed silicon powder, keeping the temperature, stirring and reacting for 2 hours, continuously dripping alkali liquor, continuously stirring and reacting for 6 hours after dripping, and cooling to room temperature to obtain silica sol;
in the preparation process of the silica sol, the mass concentration of ammonia water is 20%, the concentration of sodium hydroxide solution is 0.1mol/L, and the mass ratio of silicon powder to ammonia water to sodium hydroxide solution is 1:0.3:10; in the preparation process of the silica sol, the alkali liquor is sodium hydroxide solution with the concentration of 0.5mol/L, the dripping time is controlled to be 1h, and the dripping quality of the alkali liquor is 4 times that of the silicon powder.
Comparative example 1
The preparation method of the low-temperature polysilicon film is different from that of example 1 in that the composite liquid is not coated on the substrate, the polysilicon film is directly prepared on the substrate, and the other preparation methods are the same as those of example 1.
Comparative example 2
A preparation method of a low-temperature polysilicon film is different from that of example 1 in that a substrate is coated with a silica sol (original composite liquid is replaced), the preparation method of the silica sol is the same as that of example 1, and the rest preparation methods are the same as that of example 1.
Comparative example 3
A preparation method of a low-temperature polysilicon film is different from that of the embodiment 1 in that a composite liquid is not coated on a substrate, a layer of copper silicide is directly and magnetically sputtered on the substrate, the thickness of the copper silicide is the same as that of the embodiment 1, and the rest preparation methods are the same as that of the embodiment 1.
Experimental example
The polysilicon thin films prepared in example 1 and comparative examples 1 to 3 were examined, including the properties of grain uniformity, grain size, crystallization rate and theoretical photoelectric conversion rate of the polysilicon thin films, wherein the examination of grain uniformity and grain size was observed under a Scanning Electron Microscope (SEM), and the grain uniformity was classified as: grade 1-5, with grade 1 being the best uniformity and grade 5 being the worst.
The test results are shown in table 1 below:
TABLE 1 polysilicon film test results
As can be seen from the data in Table 1, the polycrystalline silicon film prepared by the embodiment of the invention has higher uniformity of crystal grains, the grain size of the crystal grains can reach 0.39-0.42 mu m, the crystallization rate is in a relatively high range (83.4% -90.5%), the theoretical photoelectric conversion rate can also reach 18.1% -21.0%, and the performance of the polycrystalline silicon film prepared by the conventional low-temperature method is stronger.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms should not be understood as necessarily being directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (10)
1. The preparation method of the low-temperature polysilicon film is characterized by comprising the following steps:
step 1: preparing a glass substrate as a substrate, cleaning the surface of the glass substrate, and drying the glass substrate in an oven;
step 2: preparing copper silicide porous microspheres, and mixing the copper silicide porous microspheres with silica sol to form a composite liquid;
step 3: coating a composite liquid on a substrate, and forming a composite layer after treatment at a certain temperature;
step 4: depositing an amorphous silicon layer on the composite layer by a chemical vapor deposition method;
step 5: and after preheating the substrate, carrying out low-temperature laser treatment on the amorphous silicon layer to obtain the polycrystalline silicon film.
2. The method for preparing a low temperature polysilicon thin film according to claim 1, wherein in the step 1, the softening temperature of the glass substrate is higher than 600 ℃ and the thickness is 500-1000 μm.
3. The method for preparing a low-temperature polysilicon thin film according to claim 1, wherein in the step 2, the method for preparing copper silicide porous microspheres comprises the following steps:
s1: weighing ethyl orthosilicate, adding the ethyl orthosilicate into absolute ethyl alcohol, and fully and uniformly stirring to form an ethyl orthosilicate solution;
s2: weighing cuprous chloride, adding the cuprous chloride into ammonia water, and stirring at 40-50 ℃ until the cuprous chloride is completely dissolved to obtain cuprous chloride solution;
s3: dropwise adding an ethyl orthosilicate solution into a continuously stirred cuprous chloride solution at room temperature, wherein the stirring speed is 800-1000r/min, and after all the stirring speed is reduced to 400-500r/min, continuously stirring for 8-12h at room temperature to obtain a mixed reaction solution;
s4: centrifugally filtering the mixed reaction solution obtained in the step S3, collecting solid precipitate, washing to be neutral by using deionized water, and drying in an oven to obtain microsphere precursors;
s5: heating the microsphere precursor to 800-1000 ℃ under the protection of inert gas, sintering for 3-5h, then introducing hydrogen, performing heat preservation and sintering for 1h again, and cooling to room temperature along with a furnace to obtain the copper silicide porous microspheres.
4. The method for preparing a low-temperature polysilicon film according to claim 3, wherein in S1, the mass ratio of the tetraethoxysilane to the absolute ethyl alcohol is 1:1.4-1.8; in S2, the mass fraction of the ammonia water is 10% -20%, and the mass ratio of the cuprous chloride to the ammonia water is 1:6-10; in S3, the mass ratio of the tetraethoxysilane solution to the cuprous chloride solution is 1:2.1-4.2; s4, the temperature of the oven is 100-120 ℃ and the drying time is 4-8h; in S5, the hydrogen gas is introduced in an amount of 10-15% of the total gas volume.
5. The method for preparing a low-temperature polysilicon film according to claim 1, wherein in the step 2, the preparation method of the silica sol comprises the following steps:
and (3) weighing ammonia water and sodium hydroxide solution, mixing into a reaction bottle, heating to 50-60 ℃, uniformly stirring, adding the weighed silicon powder, keeping the temperature, stirring and reacting for 2 hours, continuously dripping alkali liquor, continuously stirring and reacting for 4-6 hours after dripping, and cooling to room temperature to obtain the silica sol.
6. The preparation method of the low-temperature polysilicon film according to claim 1, wherein in the preparation process of the silica sol, the mass concentration of ammonia water is 10% -20%, the concentration of sodium hydroxide solution is 0.1mol/L, and the mass ratio of silicon powder, ammonia water and sodium hydroxide solution is 1:0.1-0.3:5-10; the alkali liquor is sodium hydroxide solution with the concentration of 0.5mol/L, the dripping time is controlled to be 1h, and the dripping mass of the alkali liquor is 2-4 times of the mass of the silicon powder.
7. The method for preparing a low-temperature polysilicon film according to claim 1, wherein in the step 2, the preparation method of the composite liquid comprises the following steps: adding the copper silicide porous microspheres into the silica sol, and fully stirring for 8-12 hours at room temperature to obtain a composite solution; wherein the mass ratio of the copper silicide porous microsphere to the silica sol is 1:4-8.
8. The method for preparing a low-temperature polysilicon film according to claim 1, wherein in the step 3, the composite liquid is coated for a plurality of times, the thickness of the single coating is 20-50 μm, and the number of times of the plurality of times of the coating is 2-5 times; the certain temperature is that heating to be completely dried at 80 ℃, then heating to 250-300 ℃ and preserving heat for 2-5h.
9. The method for preparing a low-temperature polysilicon film according to claim 1, wherein in the step 4, the thickness of the amorphous silicon layer formed by chemical vapor deposition is 250-350nm; during deposition, the substrate temperature is 220-250deg.C, silane (SiH 4 ) With hydrogen (H) 2 ) The volume flow ratio of (2) is 1:8.
10. The method for preparing a low-temperature polysilicon film according to claim 1, wherein in the step 5, the temperature of the substrate preheating treatment is 200-300 ℃; the low-temperature laser treatment is dehydrogenation treatment firstly, and then excimer laser annealing treatment is carried out; dehydrogenation is to reduce the hydrogen content in the amorphous silicon layer to within 3%; excimer laser annealingThe laser pulse frequency of fire is 450-550Hz, the light spot width is 100-300 μm, and the laser energy density is 350-450mJ/cm 2 The scanning speed is 5-6mm/s.
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| JPH07106592A (en) * | 1993-09-29 | 1995-04-21 | Semiconductor Energy Lab Co Ltd | Semiconductor device and its forming method |
| KR960039282A (en) * | 1995-04-01 | 1996-11-25 | 문정환 | Wiring Manufacturing Method of Semiconductor Device |
| JP2005057155A (en) * | 2003-08-07 | 2005-03-03 | Toppoly Optoelectronics Corp | Crystallization method of polycrystalline silicon layer |
| CN102891107A (en) * | 2012-10-19 | 2013-01-23 | 京东方科技集团股份有限公司 | Low temperature polysilicon base plate and manufacturing method thereof |
| CN115212882A (en) * | 2022-06-30 | 2022-10-21 | 浙江工业大学 | Porous copper silicide intermetallic compound material and preparation and application thereof |
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| TWI290768B (en) * | 2003-06-05 | 2007-12-01 | Au Optronics Corp | Method for manufacturing polysilicon film |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH07106592A (en) * | 1993-09-29 | 1995-04-21 | Semiconductor Energy Lab Co Ltd | Semiconductor device and its forming method |
| KR960039282A (en) * | 1995-04-01 | 1996-11-25 | 문정환 | Wiring Manufacturing Method of Semiconductor Device |
| JP2005057155A (en) * | 2003-08-07 | 2005-03-03 | Toppoly Optoelectronics Corp | Crystallization method of polycrystalline silicon layer |
| CN102891107A (en) * | 2012-10-19 | 2013-01-23 | 京东方科技集团股份有限公司 | Low temperature polysilicon base plate and manufacturing method thereof |
| CN115212882A (en) * | 2022-06-30 | 2022-10-21 | 浙江工业大学 | Porous copper silicide intermetallic compound material and preparation and application thereof |
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