CN101771096B - Solar battery of pn knot generated by epitaxy based on heavily-doped UMG silicon and preparation method - Google Patents
Solar battery of pn knot generated by epitaxy based on heavily-doped UMG silicon and preparation method Download PDFInfo
- Publication number
- CN101771096B CN101771096B CN2010100400491A CN201010040049A CN101771096B CN 101771096 B CN101771096 B CN 101771096B CN 2010100400491 A CN2010100400491 A CN 2010100400491A CN 201010040049 A CN201010040049 A CN 201010040049A CN 101771096 B CN101771096 B CN 101771096B
- Authority
- CN
- China
- Prior art keywords
- silicon
- layer
- umg
- battery sheet
- heavily doped
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 145
- 239000010703 silicon Substances 0.000 title claims abstract description 145
- 238000000407 epitaxy Methods 0.000 title claims abstract description 35
- 238000002360 preparation method Methods 0.000 title claims abstract description 15
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 144
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 88
- 229910052581 Si3N4 Inorganic materials 0.000 claims abstract description 48
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims abstract description 48
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 43
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 43
- 238000000034 method Methods 0.000 claims abstract description 30
- 239000002994 raw material Substances 0.000 claims abstract description 27
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052709 silver Inorganic materials 0.000 claims abstract description 18
- 239000004332 silver Substances 0.000 claims abstract description 18
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 16
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000013078 crystal Substances 0.000 claims abstract description 8
- 239000011265 semifinished product Substances 0.000 claims description 46
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical group [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 19
- 229910052796 boron Inorganic materials 0.000 claims description 19
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 17
- 239000004411 aluminium Substances 0.000 claims description 15
- 230000015572 biosynthetic process Effects 0.000 claims description 14
- 238000007650 screen-printing Methods 0.000 claims description 14
- 239000002019 doping agent Substances 0.000 claims description 12
- 238000002156 mixing Methods 0.000 claims description 12
- 238000005245 sintering Methods 0.000 claims description 12
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims description 11
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 10
- 229910052698 phosphorus Inorganic materials 0.000 claims description 10
- 239000011574 phosphorus Substances 0.000 claims description 10
- 125000004437 phosphorous atom Chemical group 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 9
- 238000000137 annealing Methods 0.000 claims description 6
- 238000005530 etching Methods 0.000 claims description 6
- 238000007711 solidification Methods 0.000 claims description 6
- 230000008023 solidification Effects 0.000 claims description 6
- 238000004528 spin coating Methods 0.000 claims description 6
- RLOWWWKZYUNIDI-UHFFFAOYSA-N phosphinic chloride Chemical group ClP=O RLOWWWKZYUNIDI-UHFFFAOYSA-N 0.000 claims description 2
- 239000002210 silicon-based material Substances 0.000 abstract description 6
- 230000009466 transformation Effects 0.000 abstract 1
- 238000005516 engineering process Methods 0.000 description 17
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 16
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 12
- 239000012535 impurity Substances 0.000 description 11
- 230000005611 electricity Effects 0.000 description 10
- 239000004065 semiconductor Substances 0.000 description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 8
- 238000004140 cleaning Methods 0.000 description 8
- 239000008367 deionised water Substances 0.000 description 8
- 239000007789 gas Substances 0.000 description 8
- 238000009616 inductively coupled plasma Methods 0.000 description 8
- 229910017604 nitric acid Inorganic materials 0.000 description 8
- 229910052760 oxygen Inorganic materials 0.000 description 8
- 239000001301 oxygen Substances 0.000 description 8
- 239000002002 slurry Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 229920005591 polysilicon Polymers 0.000 description 7
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 6
- 238000005498 polishing Methods 0.000 description 6
- 238000005286 illumination Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 4
- 238000005282 brightening Methods 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000010409 thin film Substances 0.000 description 4
- 239000010408 film Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 230000001172 regenerating effect Effects 0.000 description 2
- 229910000077 silane Inorganic materials 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 125000004429 atom Chemical group 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/547—Monocrystalline silicon PV cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Photovoltaic Devices (AREA)
Abstract
The invention discloses a solar battery of a PN knot generated by epitaxy based on heavily-doped UMG silicon, which comprises a plurality of battery pieces, wherein the battery pieces are sequentially an aluminum electrode layer, a first silicon nitride layer, a first silicon dioxide layer, a heavily-doped UMG silicon layer, a lightly-doped silicon epitaxial layer, a second silicon dioxide layer, a second silicon nitride layer and a plurality of heavily-doped areas from bottom to top; the conductive type of the lightly-doped silicon epitaxial layer is opposite to the conductive type of the heavily-doped UMG silicon layer; the conductive type of the heavily-doped areas is opposite to the conductive type of the heavily-doped UMG silicon layer; and silver electrodes are arranged on the upper surfaces of the heavily-doped areas and the second silicon nitride layer. The invention also provides a preparation method of the battery pieces. The invention utilizes the raw material of UMG silicon with low cost, selects a heavily-doped technique to grow heavily-doped UMG silicon crystals and grows a high-quality silicon film by epitaxy to prepare the battery pieces. Compared with a method of directly utilizing a high-quality bulk silicon material, the cost is much lower. Compared with battery pieces prepared by directly utilizing a lightly-doped UMG silicon material, the photoelectric transformation efficiency is much higher.
Description
Technical field
The invention belongs to the Application of Solar Energy field, relate in particular to a kind of based on heavily doped UMG silicon epitaxy generate the pn knot efficiently, solar cell and preparation method cheaply.
Background technology
Entered since 21 century, the mankind face serious energy crisis.Fossil energies such as oil will be soon depleted, and human demand to the energy increases day by day.This makes regenerative resource become the focus of concern.In all regenerative resources, solar energy is a kind of widely distributed, nexhaustible clean energy resource, has great application prospect.Solar cell is a kind of to be the semiconductor device of electric energy with conversion of solar energy, but the price of solar cell is still high at present, especially the silicon solar cell cost that occupies photovoltaic market 90% above share is still very high, and this has had a strong impact on the popularization and the use of silicon solar cell.
In the preparation technology of the silicon solar cell of current trend, the silicon solar cell sheet is raw material often with the high purity polycrystalline silicon, becomes silicon crystal through casting or vertical pulling, waits subsequent technique to prepare through section then.In the high purity polycrystalline silicon purification technique, Siemens Method, silane thermal decomposition process have occupied the share more than 90%.But the silicon material purity that utilizes these methods to obtain can reach 9N, and far above the 6N requirement of solar energy level silicon, and cost is difficult to reduce.Under all silicon raw materials all were situation with the high purity polycrystalline silicon of chemical method preparation, the silicon materials cost accounted for about 30% of battery sheet total cost, becomes the main bottleneck of restriction solar cell industry large-scale application in national economy.Corresponding with high purity polycrystalline silicon is high grade metallic silicon (UMG silicon), its cost have only high purity polycrystalline silicon 1/5th so that lower, therefore be expected to replace Siemens Method and significantly reduce material cost.
At present, only have several companies such as CSI and CaliSolar to use UMG silicon to prepare the body silicon solar cell, but the efficient of these batteries is unstable and be lower than 14%, its main cause is that its impurity content is than the polysilicon height of Siemens Method and silane thermal decomposition process preparation.Document (' The impact of siliconfeed stock on the PV module cost ', G.del Coso, C.del Canizo, W.C.Sinke, Solar Energy Materials﹠amp are arranged; Solar Cells, 2009) point out, when the efficient of UMG silicon solar cell is lower than 14%, it will lose with the competition of ordinary silicon solar cell in price advantage.Therefore, directly use UMG silicon to prepare solar cell and remain a great problem.Utilizing UMG growing epitaxial silicon thin film silicon to be used to prepare solar cell is new a selection of reducing this.At present report has UMG silicon that utilization gently mixes as substrate epitaxial silicon, adopt prepared battery then with common crystal silicon cell technology basically identical, its battery efficiency still than, even less than 14%, see document Filip Duerinckx, etc., Prog.Photovolt:Res.Appl.2005; 13:673-690.Its main cause is owing to impurity content in the UMG silicon is higher, and the impurity of substrate descends film quality, thereby finally influences battery efficiency very easily by the diffuse pollution film in thin film growth process.Thereby, seek a rational approach and UMG silicon is carried out modification and develop new battery preparation technique being very important utilizing UMG growing epitaxial silicon thin film silicon to be used to prepare efficient, low-cost solar cell.
Summary of the invention
The invention provides a kind of low cost, the high efficiency solar cell that generates the pn knot based on heavily doped UMG silicon epitaxy.
A kind of solar cell based on heavily doped UMG silicon epitaxy generation pn knot comprises some battery sheets, and described battery sheet is followed successively by from the bottom to top:
The aluminium electrode layer;
First silicon nitride layer;
First silicon dioxide layer;
Heavily doped UMG silicon layer, the conduction type of this layer are p type or n type;
Gently mix silicon epitaxy layer, the conductivity type opposite of conduction type of this layer and heavily doped UMG silicon layer, for example when the conduction type of heavily doped UMG silicon layer was the p type, the conduction type of then gently mixing silicon epitaxy layer was the n type;
Second silicon dioxide layer;
Second silicon nitride layer;
Wherein gently mix in the silicon epitaxy layer described, be distributed with some heavily doped zones at the surperficial position of closing on second silicon dioxide layer, the conductivity type opposite of the conduction type in this heavily doped zone and heavily doped UMG silicon layer, for example when the conduction type of heavily doped UMG silicon layer was the p type, then the conduction type in heavily doped zone was the n type;
Upper surface at the described heavily doped zone and second silicon nitride layer is provided with silver electrode.
Solar cell is made of a lot of battery sheets, and the present invention improves the structure of battery sheet in the prior art, obtains can utilizing existing technology groups to dress up solar cell again behind the battery sheet.
The present invention also provides a kind of preparation method of battery sheet of described solar cell, comprises the steps:
(1) with monocrystalline silicon or the directional solidification method growing polycrystalline silicon of UMG silicon, obtain the raw material silicon ingot with Grown by CZ Method crystal face (100),
Dopant is a boron in the described raw material silicon ingot, and doping content is 10
18～10
20Individual boron atom/cm
3, doping content can be more preferably 10
19～10
20Individual boron atom/cm
3, the UMG silicon chip is the most obvious to the constraint effect of intrinsic metal impurities under this doping content, can farthest reduce effects of Metallic Impurities;
(2) the raw material silicon ingot of gained in the step (1) is sliced into for square and thickness be the thin slice of 100～300 μ m, be chemically mechanically polished to its surface-brightening then, adopt the conventional cleaning of semiconductor to clean, chemical polishing, with washed with de-ionized water number time, the infrared lamp oven dry obtains UMG silicon chip (being the heavily doped UMG silicon layer in the battery sheet);
(3) with the UMG silicon chip of gained in the step (2) as substrate, use the CVD technology gently to mix silicon epitaxy layer and obtain semi-finished product battery sheet in the growth of UMG silicon chip upper surface;
The described thickness of gently mixing silicon epitaxy layer is 10～100 μ m, and the dopant of gently mixing silicon epitaxy layer is POCl
3Or PH
3, doping content is 10
15～10
17Individual phosphorus atoms/cm
3, doping content can be more preferably 10
15～10
16Individual phosphorus atoms/cm
3, the easiest formation saltant pn knot under this doping content, and the abrupt junction width in heavily doped UMG silicon that forms in this case can ignore, so effects of Metallic Impurities can be ignored;
(4) use CF
4With oxygen as working gas, utilize the inductively coupled plasma generator to produce plasma, remove semi-finished product battery sheet periphery and may cause the PN junction that leaks electricity;
(5) the semi-finished product battery sheet behind the PN junction that may cause leaking electricity removed that step (4) is obtained carries out surface-texturing and handles; Adopt the conventional cleaning of semiconductor to clean after texture is finished, again with washed with de-ionized water number time, the infrared lamp oven dry obtains the semi-finished product battery sheet after the texturing;
If the semi-finished product battery sheet of removing behind the PN junction that may cause leaking electricity is a monocrystalline silicon, be that 1.5% the KOH aqueous solution carries out the surface-texturing processing then with mass percent concentration;
If the semi-finished product battery sheet of removing behind the PN junction that may cause leaking electricity is a polysilicon, is nitric acid with volume ratio then: hydrofluoric acid: the mixed solution of acetate=3: 1: 10 carries out the surface-texturing processing;
Wherein said nitric acid adopts the red fuming nitric acid (RFNA) of mass percent concentration more than 50%, and commonly used is 50～80%;
The mass percent concentration of wherein said hydrofluoric acid is 30～70%;
(6) upper surface of the semi-finished product battery sheet after texturing formation thickness is second silicon dioxide layer of 2～10nm, and the upper surface formation thickness at described second silicon dioxide layer is second silicon nitride layer of 70～90nm then;
It is 2～10nm, first silicon dioxide layer that the lower surface of the semi-finished product battery sheet after texturing forms thickness, and the lower surface formation thickness at described first silicon dioxide layer is first silicon nitride layer of 70～90nm then;
Described first silicon dioxide layer and second silicon dioxide layer generally form simultaneously, and described first silicon nitride layer and second silicon nitride layer generally also form simultaneously.
When forming first silicon nitride layer and second silicon nitride layer, can adopt the PECVD technology.
(7) use CF
4With oxygen as working gas, formed second silicon dioxide layer of upper surface and second silicon nitride layer of the semi-finished product battery sheet after utilizing inductively coupled plasma generator generation plasma to texturing in the step (6) carry out etching, form grid shape window, wherein the wide 0.1～0.5mm of each grid line;
(8) in grid shape window place's silk screen printing phosphorus source and annealing form heavily doped zone, obtain forming the semi-finished product battery sheet behind the heavily doped zone, wherein phosphorus doping density is 10
18～10
19Individual phosphorus atoms/cm
3, doping content can be more preferably 1 * 10
19～9 * 10
19Individual phosphorus atoms/cm
3, emitter best results that heavily doped zone forms under this doping content and silicon chip and electrode can form good Ohmic contact;
(9) the lower surface spin coating aluminium paste of the semi-finished product battery sheet after forming heavily doped zone and sintering form the aluminium electrode layer, in heavily doped zone and the upper surface of second silicon nitride layer form silver electrode and obtain solar cell piece;
At first form grid in heavily doped region upper surface when forming silver electrode, and then on the grid and second silicon nitride layer, form busbar, carry out sintering at last and obtain solar cell piece by silk screen printing silver slurry by silk screen printing silver slurry.
The style of described silver electrode is that grid adds bus-bar structure, and the grid line width is identical with grid shape window width, and the busbar width is 1.5～3mm.Sintering temperature is 750 ℃～850 ℃, and the time is 2～4min.
Because heavily doped UMG silicon layer conduction type can be p type or n type; What above method was explained is that heavily doped UMG silicon layer conduction type is the p type, and when heavily doped UMG silicon layer conduction type was the n type, the preparation method was as follows:
(1) with monocrystalline silicon or the directional solidification method growing polycrystalline silicon of UMG silicon, obtain the raw material silicon ingot with Grown by CZ Method crystal face (100),
Dopant is a phosphorus in the described raw material silicon ingot, and doping content is 10
18～10
20Individual phosphorus atoms/cm
3, doping content can be more preferably 10
19～10
20Individual phosphorus atoms/cm
3, the UMG silicon chip is the most obvious to the constraint effect of intrinsic metal impurities under this doping content, can farthest reduce effects of Metallic Impurities;
(2) the raw material silicon ingot of gained in the step (1) is sliced into for square and thickness be the thin slice of 100～300 μ m, be chemically mechanically polished to its surface-brightening then, adopt the conventional cleaning of semiconductor to clean, chemical polishing, with washed with de-ionized water number time, the infrared lamp oven dry obtains UMG silicon chip (being the heavily doped UMG silicon layer in the battery sheet);
(3) with the UMG silicon chip of gained in the step (2) as substrate, use the CVD technology gently to mix silicon epitaxy layer and obtain semi-finished product battery sheet in the growth of UMG silicon chip upper surface;
The described thickness of gently mixing silicon epitaxy layer is 10～100 μ m, and the dopant of gently mixing silicon epitaxy layer is B
2H
6, doping content is 10
15～10
17Individual boron atom/cm
3, doping content can be more preferably 10
15～10
16Individual boron atom/cm
3, the easiest formation saltant pn knot under this doping content, and the abrupt junction width in heavily doped UMG silicon that forms in this case can ignore, so effects of Metallic Impurities can be ignored;
(4) use CF
4With oxygen as working gas, utilize the inductively coupled plasma generator to produce plasma, remove semi-finished product battery sheet periphery unnecessary promptly may cause the PN junction that leaks electricity;
(5) the semi-finished product battery sheet behind the PN junction that may cause leaking electricity removed that step (4) is obtained carries out surface-texturing and handles; Adopt the conventional cleaning of semiconductor to clean after texture is finished, again with washed with de-ionized water number time, the infrared lamp oven dry obtains the semi-finished product battery sheet after the texturing;
If the semi-finished product battery sheet of removing behind the PN junction that may cause leaking electricity is a monocrystalline silicon, be that 1.5% the KOH aqueous solution carries out the surface-texturing processing then with mass percent concentration;
If the semi-finished product battery sheet of removing behind the PN junction that may cause leaking electricity is a polysilicon, is nitric acid with volume ratio then: hydrofluoric acid: the mixed solution of acetate=3: 1: 10 carries out the surface-texturing processing;
Wherein said nitric acid adopts the red fuming nitric acid (RFNA) of mass percent concentration more than 50%, and commonly used is 50～80%;
The mass percent concentration of wherein said hydrofluoric acid is 30～70%;
(6) upper surface of the semi-finished product battery sheet after texturing formation thickness is second silicon dioxide layer of 2～10nm, and the upper surface formation thickness at described second silicon dioxide layer is second silicon nitride layer of 70～90nm then;
It is first silicon dioxide layer of 2～10nm that the lower surface of the semi-finished product battery sheet after texturing forms thickness, and the lower surface formation thickness at described first silicon dioxide layer is first silicon nitride layer of 70～90nm then;
Described first silicon dioxide layer and second silicon dioxide layer generally form simultaneously, and described first silicon nitride layer and second silicon nitride layer generally also form simultaneously.
When forming first silicon nitride layer and second silicon nitride layer, can adopt the PECVD technology.
(7) use CF
4With oxygen as working gas, formed second silicon dioxide layer of upper surface and second silicon nitride layer of the semi-finished product battery sheet after utilizing inductively coupled plasma generator generation plasma to texturing in the step (6) carry out etching, form grid shape window, wherein the wide 0.1～0.5mm of each grid line;
(8) in grid shape window place's silk screen printing boron source and annealing form heavily doped zone, obtain forming the semi-finished product battery sheet behind the heavily doped zone, wherein boron doping concentration is 10
18～10
19Individual boron atom/cm
3, doping content can be more preferably 1 * 10
19～9 * 10
19Individual boron atom/cm
3, emitter best results that heavily doped zone forms under this doping content and silicon chip and electrode can form good Ohmic contact;
(9) the lower surface spin coating aluminium paste of the semi-finished product battery sheet after forming heavily doped zone and sintering form the aluminium electrode layer, in heavily doped zone and the upper surface of second silicon nitride layer form silver electrode and obtain solar cell piece;
At first form grid in heavily doped region upper surface when forming silver electrode, and then on the grid and second silicon nitride layer, form busbar, carry out sintering at last and obtain solar cell piece by silk screen printing silver slurry by silk screen printing silver slurry.
The style of described silver electrode is that grid adds bus-bar structure, and the grid line width is identical with grid shape window width, and the busbar width is 1.5～3mm.Sintering temperature is 750 ℃～850 ℃, and the time is 2～4min.
The present invention proposes the backing material of heavily doped UMG silicon as the thin film silicon solar cell, and adopts rational battery process to prepare silicon solar cell.The solar cell of this prepared has three advantages that prior art did not have:
(1) but utilize UMG silicon raw material cheaply, go out thin high quality monocrystalline silicon or polysilicon membrane by the heavily doped UMG silicon crystal epitaxial growth of selecting the heavy doping technology growth to go out to need and prepare battery, cost is much lower with respect to directly utilizing the high quality bulk silicon materials, and the battery that photoelectric conversion efficiency is gently mixed the silicon materials preparation with respect to direct utilization wants high a lot.
(2) carry out heavily doped to the UMG raw material, can effectively fetter effect to the intrinsic metal impurities of UMG silicon chip, avoided intrinsic metal impurities in the common UMG silicon problem when epitaxial growth, can grow the monocrystalline silicon or the polysilicon membrane of better quality to the epitaxial loayer diffusion.
(3) the heavily doped UMG silicon that utilizes certain conduction type has been simplified battery process as gently the mixing epitaxial loayer and can directly obtain the pn knot of substrate epitaxial growth conductivity type opposite.The battery manufacturing process that the present invention proposes can not only reduce the production cost of solar cell, the more important thing is that it can improve the efficient of silicon-film solar-cell.Can obtain large tracts of land single crystal silicon solar cell average efficiency 16.5%, polycrystalline silicon solar cell efficient can reach (AM1.5, intensity of illumination 100mW/cm more than 15%
2, 25 ℃).
In addition, the technological process simple possible that relates among the present invention has application promise in clinical practice, and this has established technical foundation for the extensive popularization of low-cost UMG silicon in solar cell.
Description of drawings
Fig. 1 is the structural representation of the battery sheet of the heavily doped UMG solar cell of the present invention.
Fig. 2 is preparation method's flow chart of the battery sheet of the heavily doped p type of the present invention UMG solar cell.
Fig. 3 is preparation method's flow chart of the battery sheet of the heavily doped n type of the present invention UMG solar cell.
Embodiment
Referring to Fig. 1, the present invention is based on the battery sheet that solar cell adopted that heavily doped UMG silicon epitaxy generates the pn knot, be followed successively by from the bottom to top:
First silicon nitride layer 2;
First silicon dioxide layer 3;
Heavily doped UMG silicon layer 4, the conduction type of this layer can be p type or n type;
Gently mix silicon epitaxy layer 5, the conductivity type opposite of conduction type of this layer and heavily doped UMG silicon layer 4;
Second silicon dioxide layer 6;
Second silicon nitride layer 7;
Wherein gently mix in the silicon epitaxy layer 5 described, be distributed with at the surperficial position of closing on second silicon dioxide layer 6 some heavily doped regional 8, the conductivity type opposite of this heavily doped regional 8 conduction type and heavily doped UMG silicon layer 4;
Described heavily doped regional 8 and the upper surface of second silicon nitride layer 7 be provided with silver electrode 9.
Wherein pn tie region 10 is the working region of battery sheet, is positioned at heavily doped UMG silicon layer 4 and gently mixes the position that silicon epitaxy layer 5 has a common boundary.
Referring to Fig. 2, the process of battery sheet for preparing heavily doped p type UMG solar cell is as follows:
UMG silicon is obtained the raw material silicon ingot with Grown by CZ Method (100) monocrystalline silicon, and dopant is a boron in the raw material silicon ingot, and doping content is 5 * 10
19Cm
-3(implication is 5 * 10
19Individual foreign atom/cm
3);
The raw material silicon ingot is cut into square and thickness is the thin slice of 200 μ m; Thin slice is carried out mechanical polishing to its surface-brightening, adopt the conventional cleaning of semiconductor to clean, chemical polishing, with washed with de-ionized water number time, the infrared lamp oven dry obtains the UMG silicon chip.
The UMG silicon chip as substrate, is used the CVD technology gently to mix silicon epitaxy layer in the growth of UMG silicon chip surface and obtains semi-finished product battery sheet, and gently mixing silicon epitaxy layer thickness is 55 μ m, mixes gently that dopant is PH in the silicon epitaxy layer
3, doping content is 5 * 10
17Cm
-3
Use CF
4With oxygen as working gas, utilize the inductively coupled plasma generator to produce plasma, remove semi-finished product battery sheet periphery and may cause the PN junction that leaks electricity;
Be that 1.5% KOH solution carries out surface-texturing and handles with percent by volume again, the battery sheet that texture is finished adopts the conventional cleaning of semiconductor to clean, again with washed with de-ionized water number time, and the infrared lamp oven dry.
Texturing is handled the back and is formed 5nm second silicon dioxide layer at semi-finished product battery sheet upper surface, utilizes the PECVD technology at second silicon nitride layer of the second silicon dioxide layer upper surface deposit thickness for 70nm again;
Form 5nm first silicon dioxide layer at semi-finished product battery sheet lower surface simultaneously, utilize the PECVD technology again at first silicon nitride layer of the first silicon dioxide layer lower surface deposit thickness for 70nm.
Use CF
4With oxygen as working gas, utilize the inductively coupled plasma generator to produce plasma second silicon nitride and second silicon oxide layer carried out etching, form grid shape window, wherein the wide 0.15mm of each grid line;
Also annealing forms heavily doped zone in grid shape window place's silk screen printing phosphorus source, and doping content is 3 * 10
19Cm
-3
The first silicon nitride layer lower surface spin coating aluminium paste and sintering form the aluminium electrode layer.
The silver-colored slurry of the i.e. upper surface silk screen printing of first silicon nitride layer formed bus-bar structure in heavily doped zone after heavily doped region upper surface silk screen printing silver slurry formed grid, and the grid line width is identical with grid shape window width in the grid, and the busbar width is 1.5mm.
Carry out sintering at last and obtain the battery sheet, temperature is 750 ℃, and the time is 4min.
This battery sheet is tested, and efficient reaches 16.2% (AM1.5, intensity of illumination 100mW/cm
2, 25 ℃), unglazed decay.
Embodiment 2
Technology according to embodiment 1, the battery sheet for preparing heavily doped p type UMG solar cell, difference only is the polysilicon of raw material silicon ingot for adopting UMG silicon to obtain with the directional solidification method growth, and to adopt volume ratio when surface-texturing is handled be nitric acid: hydrofluoric acid: the solution of acetate=3: 1: 10 carries out the texturing processing.
Wherein the mass percent concentration of nitric acid is 65%, and the mass percent concentration of hydrofluoric acid is 49%.
The efficient of the battery sheet that obtains at last reaches 15.4% (AM1.5, intensity of illumination 100mW/cm
2, 25 ℃), unglazed decay.
Embodiment 3
Referring to Fig. 3, the process of battery sheet for preparing heavily doped n type UMG solar cell is as follows:
UMG silicon is obtained the raw material silicon ingot with Grown by CZ Method (100) monocrystalline silicon, and dopant is a phosphorus in the raw material silicon ingot, and doping content is 2 * 10
20Cm
-3
The raw material silicon ingot is cut into square and thickness is the thin slice of 150 μ m; Thin slice is carried out mechanical polishing to its surface-brightening, adopt the conventional cleaning of semiconductor to clean, chemical polishing, with washed with de-ionized water number time, the infrared lamp oven dry obtains the UMG silicon chip.
The UMG silicon chip as substrate, is used the CVD technology gently to mix silicon epitaxy layer in the growth of UMG silicon chip surface and obtains semi-finished product battery sheet, and gently mixing silicon epitaxy layer thickness is 25 μ m, mixes gently that dopant is B in the silicon epitaxy layer
2H
6, doping content is 10
17Cm
-3
Use CF4 and oxygen as working gas, utilize the inductively coupled plasma generator to produce plasma, remove semi-finished product battery sheet periphery and may cause the PN junction that leaks electricity;
Be that 1.5% KOH solution carries out surface-texturing and handles with percent by volume again, the battery sheet that texture is finished adopts the conventional cleaning of semiconductor to clean, again with washed with de-ionized water number time, and the infrared lamp oven dry.
Texturing is handled the back and is formed 6nm second silicon dioxide layer at semi-finished product battery sheet upper surface, utilizes the PECVD technology at second silicon nitride layer of the second silicon dioxide layer upper surface deposit thickness for 75nm again;
Form 6nm first silicon dioxide layer at semi-finished product battery sheet lower surface simultaneously, utilize the PECVD technology again at first silicon nitride layer of the first silicon dioxide layer lower surface deposit thickness for 75nm.
Use CF
4With oxygen as working gas, utilize the inductively coupled plasma generator to produce plasma second silicon nitride and second silicon oxide layer carried out etching, form grid shape window, wherein the wide 0.25mm of each grid line;
Also annealing forms heavily doped zone in grid shape window place's silk screen printing boron source, and doping content is 8 * 10
18Cm
-3
The first silicon nitride layer lower surface spin coating aluminium paste and sintering form the aluminium electrode layer.
The silver-colored slurry of the i.e. upper surface silk screen printing of first silicon nitride layer formed bus-bar structure in heavily doped zone after heavily doped region upper surface silk screen printing silver slurry formed grid, and the grid line width is identical with grid shape window width in the grid, and the busbar width is 2mm.
Carry out sintering at last and obtain the battery sheet, temperature is 800 ℃, and the time is 3min.
This battery sheet is tested, and efficient reaches 17.1% (AM1.5, intensity of illumination 100mW/cm
2, 25 ℃), unglazed decay.
Technology according to embodiment 3, the battery sheet for preparing heavily doped n type UMG solar cell, difference only is the polysilicon of raw material silicon ingot for adopting UMG silicon to obtain with the directional solidification method growth, and to adopt volume ratio when surface-texturing is handled be nitric acid: hydrofluoric acid: the solution of acetate=3: 1: 10 carries out the texturing processing.
Wherein the mass percent concentration of nitric acid is 65%, and the mass percent concentration of hydrofluoric acid is 49%.
The efficient of the battery sheet that obtains at last reaches 15.6% (AM1.5, intensity of illumination 100mW/cm
2, 25 ℃), unglazed decay.
Claims (3)
1. the solar cell based on heavily doped UMG silicon epitaxy generation pn knot comprises some battery sheets, it is characterized in that described battery sheet is followed successively by from the bottom to top:
Aluminium electrode layer (1);
First silicon nitride layer (2);
First silicon dioxide layer (3);
Heavily doped UMG silicon layer (4), the conduction type of this layer are p type or n type;
Gently mix silicon epitaxy layer (5), the conductivity type opposite of conduction type of this layer and heavily doped UMG silicon layer (4);
Second silicon dioxide layer (6);
Second silicon nitride layer (7);
Wherein gently mix in the silicon epitaxy layer (5), be distributed with some heavily doped zones (8), the conductivity type opposite of the conduction type in this heavily doped zone (8) and heavily doped UMG silicon layer (4) at the surperficial position of closing on second silicon dioxide layer (6) described;
In described heavily doped zone (8) and the upper surface of second silicon nitride layer (7) be provided with silver electrode (9).
2. the preparation method of the battery sheet of solar cell as claimed in claim 1 is characterized in that, comprises the steps:
(1) with monocrystalline silicon or the directional solidification method growing polycrystalline silicon of UMG silicon with Grown by CZ Method crystal face (100), obtain the raw material silicon ingot, dopant is a boron in the described raw material silicon ingot, and the doping content of boron is 10 in the described raw material silicon ingot
18～10
20Individual boron atom/cm
3
(2) the raw material silicon ingot with gained in the step (1) is processed into the UMG silicon chip;
(3) with the UMG silicon chip of gained in the step (2) as substrate, gently mix silicon epitaxy layer in the growth of UMG silicon chip upper surface and obtain semi-finished product battery sheet, the dopant of gently mixing silicon epitaxy layer is POCl
3Or PH
3, the described thickness of gently mixing silicon epitaxy layer is 10～100 μ m, the doping content of phosphorus is 10
15～10
17Individual phosphorus atoms/cm
3
(4) remove the unnecessary PN junction of semi-finished product battery sheet periphery;
(5) the semi-finished product battery sheet behind the unnecessary PN junction removed that step (4) is obtained carries out surface-texturing and handles, and cleans then, dries, and obtains the semi-finished product battery sheet after the texturing;
(6) upper surface of the semi-finished product battery sheet after texturing formation thickness is second silicon dioxide layer of 2～10nm, and the upper surface formation thickness at described second silicon dioxide layer is second silicon nitride layer of 70～90nm then;
It is first silicon dioxide layer of 2～10nm that the lower surface of the semi-finished product battery sheet after texturing forms thickness, and the lower surface formation thickness at described first silicon dioxide layer is first silicon nitride layer of 70～90nm then;
(7) formed second silicon dioxide layer of upper surface and second silicon nitride layer to the semi-finished product battery sheet after the texturing in the step (6) carries out etching, forms grid shape window;
(8) in grid shape window place's silk screen printing phosphorus source and annealing form heavily doped zone, phosphorus doping density is 10 in the described heavily doped zone
18～10
19Individual phosphorus atoms/cm
3
(9) the lower surface spin coating aluminium paste of the semi-finished product battery sheet after forming heavily doped zone and sintering form the aluminium electrode layer, in heavily doped zone and the upper surface of second silicon nitride layer form silver electrode, obtain solar cell piece.
3. the preparation method of the battery sheet of solar cell as claimed in claim 1 is characterized in that, comprises the steps:
(1) with monocrystalline silicon or the directional solidification method growing polycrystalline silicon of UMG silicon with Grown by CZ Method crystal face (100), obtain the raw material silicon ingot, dopant is a phosphorus in the described raw material silicon ingot, and the doping content of phosphorus is 10 in the described raw material silicon ingot
18～10
20Individual phosphorus atoms/cm
3
(2) the raw material silicon ingot with gained in the step (1) is processed into the UMG silicon chip;
(3) with the UMG silicon chip of gained in the step (2) as substrate, gently mix silicon epitaxy layer in the growth of UMG silicon chip upper surface and obtain semi-finished product battery sheet, the described dopant of gently mixing in the silicon epitaxy layer is B
2H
6, the described thickness of gently mixing silicon epitaxy layer is 10～100 μ m, the doping content of boron is 10
15～10
17Individual boron atom/cm
3
(4) remove the unnecessary PN junction of semi-finished product battery sheet periphery;
(5) the semi-finished product battery sheet behind the unnecessary PN junction removed that step (4) is obtained carries out surface-texturing and handles, and cleans then, dries, and obtains the semi-finished product battery sheet after the texturing;
(6) upper surface of the semi-finished product battery sheet after texturing formation thickness is second silicon dioxide layer of 2～10nm, and the upper surface formation thickness at described second silicon dioxide layer is second silicon nitride layer of 70～90nm then;
It is 2～10nm, first silicon dioxide layer that the lower surface of the semi-finished product battery sheet after texturing forms thickness, and the lower surface formation thickness at described first silicon dioxide layer is first silicon nitride layer of 70～90nm then;
(7) formed second silicon dioxide layer of upper surface and second silicon nitride layer to the semi-finished product battery sheet after the texturing in the step (6) carries out etching, forms grid shape window;
(8) in grid shape window place's silk screen printing boron source and annealing form heavily doped zone, boron doping concentration is 10 in the described heavily doped zone
18～10
19Individual boron atom/cm
3
(9) the lower surface spin coating aluminium paste of the semi-finished product battery sheet after forming heavily doped zone and sintering form the aluminium electrode layer, in heavily doped zone and the upper surface of second silicon nitride layer form silver electrode, obtain solar cell piece.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010100400491A CN101771096B (en) | 2010-01-19 | 2010-01-19 | Solar battery of pn knot generated by epitaxy based on heavily-doped UMG silicon and preparation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010100400491A CN101771096B (en) | 2010-01-19 | 2010-01-19 | Solar battery of pn knot generated by epitaxy based on heavily-doped UMG silicon and preparation method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101771096A CN101771096A (en) | 2010-07-07 |
| CN101771096B true CN101771096B (en) | 2011-06-15 |
Family
ID=42503815
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010100400491A Expired - Fee Related CN101771096B (en) | 2010-01-19 | 2010-01-19 | Solar battery of pn knot generated by epitaxy based on heavily-doped UMG silicon and preparation method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101771096B (en) |
-
2010
- 2010-01-19 CN CN2010100400491A patent/CN101771096B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN101771096A (en) | 2010-07-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Desa et al. | Silicon back contact solar cell configuration: A pathway towards higher efficiency | |
| CN101820007B (en) | High-conversion rate silicon and thin film compound type multijunction PIN solar cell and manufacturing method thereof | |
| CN101800266B (en) | Preparation method of selective emitting electrode crystal silicon solar battery | |
| CN102446991B (en) | Film solar battery based on crystalline silicon and manufacturing method thereof | |
| CN105870215A (en) | Rear surface passivation contact battery electrode structure and preparation method thereof | |
| CN101369612A (en) | Production method for implementing selective emitter solar battery | |
| CN105895738A (en) | Passivated contact N-type solar cell, preparation method, assembly and system | |
| CN102168256B (en) | ZnO:B film grown by utilizing MOCVD (Metal Organic Chemical Vapor Deposition) gradient doping technology and application | |
| CN100576580C (en) | The post produced velvet production process of solar cell | |
| CN207441709U (en) | A kind of crystal silicon solar energy battery structure | |
| CN107275432B (en) | Crystalline silicon solar cell and preparation method thereof | |
| CN101866963A (en) | Silicon-based multijunction multi-laminated PIN thin film solar cell with high conversion rate and production method thereof | |
| CN205657066U (en) | Back passivation contact battery electrode structure | |
| CN101483202A (en) | Multi-junction solar cell with monocrystalline silicon substrate | |
| CN103367513A (en) | Polycrystalline silicon thin film solar cell and preparation method thereof | |
| CN102790116B (en) | Upside-down mounting GaInP/GaAs/Ge/Ge four-junction solar cell and preparation method thereof | |
| CN101820006B (en) | High-conversion rate silicon-based unijunction multi-laminate PIN thin-film solar cell and manufacturing method thereof | |
| CN101894871B (en) | High-conversion rate silicon crystal and thin film compound type unijunction PIN (Positive Intrinsic-Negative) solar battery and manufacturing method thereof | |
| Hao et al. | High efficiency solar cells on direct kerfless 156 mm mono crystalline Si wafers by high throughput epitaxial growth | |
| CN205564764U (en) | Back passivation contact battery structure | |
| CN101777592B (en) | Heavily-doped UMG silicon epitaxially generated high-low junction-based solar cell and preparation method | |
| CN102544184B (en) | Personal identification number (PIN) solar battery with transverse structure and preparation method thereof | |
| CN102522453B (en) | Manufacturing method of field effect crystalline silicon solar cell | |
| CN101771096B (en) | Solar battery of pn knot generated by epitaxy based on heavily-doped UMG silicon and preparation method | |
| CN101635318A (en) | Solar energy cell |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110615 Termination date: 20180119 |