WO2011100879A1

WO2011100879A1 - Monocrystalline silicon material co-doped with gallium and indium or co-doped with gallium, indium and germanium for solar batteries and manufacturing method thereof

Info

Publication number: WO2011100879A1
Application number: PCT/CN2010/077333
Authority: WO
Inventors: 李振国
Original assignee: 西安隆基硅材料股份有限公司; 西安隆基硅技术有限公司; 宁夏隆基硅材料有限公司; 银川隆基硅材料有限公司
Priority date: 2010-02-20
Filing date: 2010-09-26
Publication date: 2011-08-25
Also published as: CN101805925B; CN101805925A

Abstract

A monocrystalline silicon material co-doped with gallium and indium or co-doped with gallium, indium and germanium for solar batteries and manufacturing method thereof are disclosed. According to the atom number per cubic centimeter, the monocrystalline silicon material consists of gallium of 1.0×10 ¹⁴-1.0×10¹⁸ /cm³, indium of 5.0×10¹²-5.0×10¹⁶/cm³, and the balance of monocrystalline silicon; or consists of gallium of 1.0×10 ¹⁴-1.0×10¹⁸ /cm³, indium of 5.0×10¹²-5.0×10¹⁶/cm³, germanium of 1.0×10¹³-1.0×10¹⁶/cm³, and the balance of monocrystalline silicon. The method for manufacturing the material comprises the following steps: charging the single crystal furnace; evacuating and checking leakage; applying the pressure and melting the charge; stabilizing, dipping a seed into the melt, shouldering; rotating the shoulder; growing with equal diameter; tailing and cooling; and shutting off the furnace. The monocrystalline silicon material for solar batteries exhibits high conversion efficiency, low light attenuation rate, low oxygen content, and oxygen atoms can be uniformly distributed in the monocrystalline silicon rod in the radial direction. High-quality monocrystalline silicon material co-doped with gallium and indium or co-doped with gallium, indium and germanium for solar batteries can be grown by controlling the heat convection of silicon melt effectively in the method.

Description

Gallium-doped indium or gallium-doped indium-doped single crystal silicon material for solar cell and preparation method thereof

The invention belongs to the technical field of single crystal silicon for solar energy, and particularly relates to a gallium-doped indium or gallium-doped indium-doped single crystal silicon material for a solar cell, and to a method for preparing the single crystal silicon material.

Background technique

Silicon crystals (monocrystalline silicon, polycrystalline silicon) solar cells have been widely used as an important clean energy source due to the availability of silicon materials and the mature production methods of solar grade high purity silicon. In the 21st century, the use of such batteries has grown tremendously.

At present, single crystal silicon for solar cells generally selects a single boron-doped element, that is, boron-doped single crystal silicon. For such boron-doped single crystal silicon, a CZ method (Czochralski, 1918) in which the production process is convenient and easy, and the boron-doped single crystal silicon rod produced has a relatively uniform resistivity distribution is widely used. The CZ method is also known as the Czochralski method and the Czochralski method. This method is particularly suitable for the growth of large diameter single crystal silicon.

Now, in the monocrystalline silicon solar cell market, boron-doped monocrystalline silicon solar cells produced by the CZ method account for the majority of the market. However, studies by Schmidt, el al. (Proceedings of the 26th IEEE Photovoltaic Specialists Conference, 1997), Glunz, et al., (Journal of Applied Physics, Sept. 2001, Vol. 90, No. 51), etc., show that In a boron-doped silicon crystal solar cell, the solar cell will have light induced degradation (LTD) under illumination, that is, the conversion efficiency of the battery is lowered. Here, conversion efficiency (also known as "photoelectric conversion efficiency") refers to the ratio of solar cells that convert incident light energy into electrical energy (generally expressed as "%").

Schmidt, et al. (Proceedings of the 26th IEEE Photovoltaic Specialists Conference, 1997), Glunz, et al. (Journal of Applied Physics, Sept. 2001, Vol. 90, No. 51), Khan et al, (Journal of Applied Physics, June 2000, Vol.87, No. 12) found that the essential cause of light decay is that the boron atoms in the boron-doped single crystal silicon and the oxygen atoms in the gap state form a boron-oxygen complex under illumination. The bulk, and the boron-oxygen complex is a deep-level recombination center, which reduces the lifetime of minority carriers, resulting in reduced conversion efficiency. According to this finding, the idea of solving the light decay is to reduce the occurrence of the boron-oxygen complex in the single crystal silicon, gp: replace the boron element with other elements, and reduce the oxygen concentration in the single crystal silicon. For the replacement of boron with other elements, Ehrstein (Journal of Electrochemical Society, 1980, Vol. 127, No. 6: 1403-1404.), Schmidt, et al. (Proceedings of the 26th IEEE Photovoltaic Specialists Conference, 13-18 , 1997), Glunz, et al. (Photovoltaic Specialists Conference, 2000. Conference Record of the Twenty-Eighth IEEE, Sept. 2000:201-204.), Glunz, et al. (Photovoltaic Specialists Conference, 2000. Conference Record of The Twenty-Eighth IEEE, Sept. 2000:201 -204. ) shows that in gallium-doped monocrystalline silicon solar cells, gallium is more difficult to form deep-level complexes with oxygen, which has a greater impact on minority life. small. The gallium-doped monocrystalline silicon solar cell developed by Shin-Etsu Semiconductor Co., Ltd., after 30 hours of illumination by a halogen lamp simulating solar light, showed no light decay.

One solution to the reduction of oxygen concentration is to fabricate boron-doped single crystal silicon using a zone melting method (i.e., FZ method) that is completely different from the CZ method. Compared with the CZ method, the boron-doped single crystal silicon produced by the FZ method has an oxygen concentration lower than one order of magnitude (i.e., at least 10 times lower than the oxygen concentration), and can effectively improve the light decay problem caused by the boron-oxygen complex. However, the FZ method is difficult to produce a large-diameter single crystal silicon rod, which cannot meet the needs of large-scale production; and the FZ method has a high production cost and has no advantage.

Another solution to reduce oxygen concentration is to improve the CZ method. For the conventional CZ method, a large number of experimental facts show that one drawback of the conventional CZ method is that it cannot effectively control the thermal convection of the silicon melt in the single crystal furnace. The thermal convection of the silicon melt in the single crystal furnace causes the oxygen in the quartz crucible to enter the silicon melt and the silicon crystal, resulting in an increase in the oxygen concentration in the single crystal silicon. If the oxygen concentration in the single crystal silicon is too high, oxygen precipitates are generated. Such oxygen precipitates not only cause mechanical damage defects such as wafer warpage of single crystal silicon, but also crystal defects such as dislocation loops. In addition, another drawback of the conventional CZ method is that as the diameter of the single crystal silicon increases, the amount of charge in the single crystal furnace also increases, and the thermal convection of the silicon melt in the crucible is also stronger, resulting in silicon melt turbulence. The flow further exacerbates the temperature fluctuations in the silicon melt, and may even cause partial remelting or supercooling of the silicon melt, making the growth quality of the single crystal silicon difficult to control and the crystal defects increasing. Therefore, although the CZ method has a process simple advantage in manufacturing large-sized single crystal silicon, if the heat convection cannot be effectively controlled, stable single crystal silicon cannot be obtained. Therefore, for the production of large-diameter single crystal silicon for solar energy, the key is to effectively control the thermal convection of the silicon melt.

To address the shortcomings of the conventional CZ method, Hoshika WA (Japanese Journal of Applied Physics, 1982, Vol. 21, No. 9:545-547), Kim, Smetana (Journal of Applied Physics, 1985, Vol. 58, No. 7:2731-2735. ) proposed a method called "MCZ" (also known as "magnetic pull method"), that is, adding a magnetic field outside the single crystal furnace, through the magnetic field Increasing the viscosity of the silicon melt, thereby reducing the thermal convection of the silicon melt in the quartz crucible, not only reduces the oxygen atoms in the quartz crucible into the silicon melt and the silicon crystal, achieves the goal of lowering the oxygen concentration, but also reduces crystal defects. The magnetic field used by the MCZ method is a magnetic field generated by a permanent magnet, and the other is a magnetic field generated by electromagnetic induction. For the design of the magnetic field, there are three types: a horizontal magnetic field, a vertical magnetic field, and a cusp magnetic field. In the design of magnetic fields, Hirata, Hoshikawad (Journal of Crystal Growth, 1989, Vol. 96, Issue 4: 747-755.) found that the unidirectional transverse magnetic field destroys the axial symmetry of the original heat flow in the CZ system. The striation defects causing the growth of the single crystal silicon rod become severe; the longitudinal magnetic field destroys the original radial symmetry of the CZ system, so that the concentration of the doped element becomes less in the radial distribution of the single crystal silicon rod. Uniform; but the hook-shaped magnetic field has no defects of the longitudinal magnetic field and the transverse magnetic field, and can effectively reduce the oxygen concentration, and the crystal defects are less. Now, some effective hook magnetic field designs have emerged, mainly using electromagnetic fields.

At present, energy issues and global climate change issues have become important issues for the sustainable development of human society. The development of solar photovoltaic industry is an important direction for human beings to obtain clean energy and break through the development problems of human beings. Therefore, large-scale, low-cost production of single crystal silicon for solar cells with low light decay, low crystal defects and large diameter is an important issue in the current development of solar photovoltaic industry. Summary of the invention

The object of the present invention is to provide a gallium-doped or gallium-doped indium-doped single crystal silicon material for a solar cell, which solves the problem that the existing boron-doped single crystal silicon material is prone to light decay when preparing a solar cell, and reduces the single crystal. The primary defects of silicon improve the quality and mechanical strength of the crystal.

Another object of the present invention is to provide a method for preparing a gallium-doped or gallium-doped indium-doped single crystal silicon material for a solar cell as described above, which effectively controls the thermal convection of the silicon melt, and grows a high-quality solar cell with gallium-doped indium or Gallium germanium indium single crystal silicon material.

The technical solution adopted by the present invention is a single crystal silicon material for a solar cell, which is composed of the following components according to the number of atoms in each cubic centimeter of single crystal silicon material:

Gallium: 1. O 10 ¹⁴ -1. O 10 ¹⁸ atoms/cm ³

Fl : 5.0 10 ¹² -5.0 10 ¹⁶ atoms/cm ³

The rest is monocrystalline silicon. Among them, the purity of gallium and indium is preferably 5N or 6N. Another technical solution adopted by the present invention is a single crystal silicon material for a solar cell, which is composed of the following components according to the number of atoms per cubic centimeter of the single crystal silicon material:

Gallium: 1. O 10 ¹⁴ -1. O 10 ¹⁸ atoms/cm ³

锗: 1. O 10 ¹³ -1. O 10 ¹⁹ atoms/cm ³

Indium: 5·0χ 10 ¹² -5·0χ 10 ¹⁶ atoms/cm ³

The rest is monocrystalline silicon. Among them, the purity of gallium, indium and antimony is preferably 5N or 6N. In order to obtain the above single crystal silicon material for a solar cell, the preparation method employed in the present invention is specifically carried out in accordance with the following steps:

1] furnace

The weighed gallium and indium or gallium, germanium and indium are doped into the silicon raw material in the quartz crucible, the quartz crucible and the seed crystal are placed in the single crystal furnace, and a magnetic field is arranged outside the single crystal furnace;

When weigh gallium and indium, weigh the number of atoms in each cubic centimeter of single crystal silicon material.

1.0x l0 ¹⁴ -1.0x l0 ¹⁸ atoms/cm ³ of gallium, 5.0 χ 10 ¹² -5.0 χ 10 ¹⁶ atoms/cm ³ of indium, the balance being silicon raw materials;

When weigh gallium, germanium and indium, weigh 1.0x l0 ¹⁴ -1.0x l0 ¹⁸ atoms/cm ³ of gallium per cubic centimeter of single crystal silicon material, 1.0x l0 ¹³ -1.0x l0 ¹⁹ atoms / cm ³ ^{^{germanium, 5.0x l0 12 -5.0x l0 16 atoms}} / cm ³ is indium, the balance being silicon feedstock;

2] Vacuuming and leak detection

Vacuuming and leak detection in the single crystal furnace; vacuuming and leak detection can be carried out by conventional methods;

3] Pressure and melt

Under the protection of an inert gas, the single crystal furnace is pressurized and heated to obtain a silicon melt; pressurization and heating can be carried out by a conventional method;

4] Stabilization

The silicon melt is subjected to a stabilization treatment for 1.5 hours to 2 hours, and the temperature of the silicon melt is stabilized at 1430 ° C -1470 ° C during the stabilization treatment;

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is 0.5-10 rpm, the pressure in the furnace is 1000-2700 Pa, the flow rate of the inert gas is controlled at 10-80 slpm, and the magnetic field strength is 500-3000 GS; Preheating the seed crystal, welding the preheated seed crystal and the stabilized silicon melt, and then performing a seeding operation; the seeding operation can be performed by a conventional method;

The parameters of seeding are: quartz crucible rotation speed 0.5-10 r/min, optimum speed 3-7 r/min, furnace pressure 1000-2700 Pa, optimum pressure in furnace 1200-2000 Pa, inert gas flow rate control At 10-80slpm, the optimum flow rate is controlled at 20-40slpm, the magnetic field strength is 500-3000GS, the distance between the guide tube and the silicon melt is 5.0-30.0mm, and the average pulling speed of the seeding is l-8mm/min;

6] After the seeding operation, the shoulder treatment, the shoulder treatment, the equal diameter growth treatment and the finishing treatment are sequentially performed to obtain a single crystal silicon rod; the shoulder, the shoulder, the equal diameter growth and the closing can be carried out by a conventional method; The parameters of the shoulder are: pulling speed 0.1-2.0mm/min, wherein the optimal pulling speed is 0.3-lmm/min, the seed crystal speed is 1.0-20.0r/min, and the optimal speed is 5.0-15.0r/min;

The parameters of the shoulder are: pulling speed 2.0-5.0mm/min _;

The parameters of equal diameter growth are: pulling speed 0.5-2mm/min, wherein the optimal pulling speed is 0.7-1.5mm/min, the speed of the ingot is 1.0-20.0r/min, and the optimal speed of the ingot is 5.0-15.0. r/min, the speed of quartz crucible is 0.5-lOr/min, the optimum speed of quartz crucible is 4-8r/min, the flow rate of inert gas in single crystal furnace is 10-80slpm, the optimum flow rate is 25-60slpm, the pressure in furnace is 1000- 2700 Pa, the optimum pressure in the furnace is 1300-2200 Pa, the magnetic field strength outside the single crystal furnace is 500-3000 GS, and the distance between the guide tube in the single crystal furnace is from the silicon melt: 5.0-30.0 mm;

The closing parameters are: The flow rate of the inert gas in the single crystal furnace is 10-50 slpm, the optimum flow rate is 20-40 slpm, the pressure in the furnace is 1000-2700 Pa, the optimum pressure in the furnace is 1200-2000 Pa, and the magnetic field outside the single crystal furnace Strength 500-3000GS.

The step 1] of the above preparation method is also characterized in that the incorporation of gallium and indium or gallium, germanium and indium into the silicon raw material is specifically:

First, a layer of silicon material is laid, and the silicon material is spread over the bottom of the quartz crucible;

(bi:) then add gallium and indium or gallium, germanium and indium;

( _{C l} ) Finally, the remaining silicon material is completely covered on the surface of gallium and indium or gallium, germanium and indium.

The above step 1] is a process of incorporating gallium and indium or gallium, germanium and indium into a silicon raw material, and a better operation is to separately prepare a high concentration of gallium-doped, germanium-doped or indium-doped silicon crystal, and then It is broken separately, and then the following steps are taken:

(a ₂ ) first layering a silicon material, and the silicon material is spread over the bottom of the quartz crucible; (b ₂ ) further injecting a certain amount of high-concentration gallium-doped and indium-doped silicon crystals or gallium-doped, antimony-doped and indium-doped silicon crystals therein;

(c ₂ ) Finally, the remaining silicon material is completely covered on the surfaces of gallium and indium or gallium, germanium and indium.

Step 1] The magnetic field disposed outside the single crystal furnace is preferably configured by two or more sets of permanent magnets, fixed by a yoke plate, uniformly distributed around the outside of the single crystal furnace, and the magnetic poles are distributed between N and S phases. The magnetic pole of the permanent magnet faces the furnace body, and the magnetic strength is 500-3000 GS.

The above steps:) laying gallium and indium or gallium, germanium and indium, or high concentration of gallium-doped and indium-doped silicon crystals or gallium-doped, germanium-doped and indium-doped silicon crystals in step (b ₂ ), It is laid in the central area of silicon raw materials.

The above seed preheating is to preheat the seed crystal height, the seed preheating height is 10-500 mm, and the preheating time is 10-60 minutes. The beneficial effects of the invention are:

(1) When the present invention is doped with gallium and indium in single crystal silicon, the concentration of gallium is between 1.0 x 10 ¹⁴ -1.0 x 10 ¹⁸ atoms/cm ³ and the concentration of indium is between 5.0 χ 10 ¹² -5.0 χ Between 10 ¹⁶ atoms/cm ³ , the resistivity of the gallium-doped indium single crystal silicon is between 0.1 and 7.0 Q'cm.

When the present invention incorporates gallium, germanium and indium in single crystal silicon, the concentration of gallium is between 1.0×10 ¹⁴ -1.0×10 ¹⁸ atoms/cm ³ , and the concentration of germanium is between 1.0×10 ¹³ -1.0×10. Between ¹⁹ atoms/cm ³ , the concentration of indium is between 5.0×10 ¹² -5.0×10 ¹⁶ atoms/cm ³ , and the resistivity of the gallium-doped indium single crystal silicon is between 0.1 and 7.0 Q′cm.

(2) mentioned herein-doped silicon single crystal gallium indium, interstitial oxygen concentration is less than ^{_{^{9.4x 10 17 atoms / C m 3}}} ; indium-gallium-doped single-crystal silicon germanium, the concentration of interstitial oxygen is less than 9.2x l0 ¹⁷ atom _S / Cm ³ . The concentration reduces the precipitation of oxygen precipitates, and the crystal defects of the single crystal silicon rods are small; and the single crystal silicon rods are moderate in strength and easy to slice, and the single crystal silicon wafer obtained by the cutting is moderate in strength, easy to process into a battery sheet, and the battery sheet is Good mechanical properties.

(3) The gallium-doped indium single crystal silicon or the gallium-doped indium-doped single crystal silicon mentioned in the present invention has a minority lifetime greater than

10μ _δ , conversion efficiency exceeds 17%.

(4) The gallium-doped indium single crystal silicon or the gallium-doped indium-doped single crystal silicon mentioned in the present invention has a reduction in conversion efficiency of less than 0.3 by illumination after stable light exposure after being fabricated into a solar cell. %. (5) The gallium-doped indium single crystal silicon or the gallium-doped indium-doped single crystal silicon mentioned in the present invention has a single-crystal silicon rod head-to-tail resistance ratio of less than 6.0. This is particularly advantageous for the low cost manufacture of the single crystal silicon mentioned in the present invention.

(6) The gallium-doped indium single crystal silicon or the gallium-doped indium-doped single crystal silicon referred to in the present invention may have an ingot diameter of more than 300 mm.

Thus, the present invention obtains single crystal silicon for solar cells having a conversion efficiency of more than 17%, low light decay, less crystal defects, and large diameter, that is, solar-grade gallium-doped indium single crystal silicon or gallium-doped indium-doped single crystal silicon. DRAWINGS

Figure 1 is a flow chart of the preparation method of the present invention;

2 is a schematic view showing the structure of a magnetic field disposed outside the single crystal furnace of the preparation method of the present invention.

In the figure, 1. permanent magnet material a, 2. permanent magnet material b, 3. permanent magnet material c, 4. permanent magnet material d, 5. magnetic soft iron a, 6. magnetic soft b, 7. furnace body.

detailed description

The invention will be described in detail below with reference to the drawings and specific embodiments.

The gallium-doped indium single crystal silicon material for solar cells of the present invention is composed of the following components in accordance with the number of atoms per cubic centimeter of single crystal silicon material:

Gallium: 1. O 10 ¹⁴ -1. O 10 ¹⁸ atoms/cm ³

Fl: 5.0 10 ¹² -5.0 10 ¹⁶ atoms/cm ³

The rest is monocrystalline silicon. Among them, the purity of gallium and indium is preferably 5N or 6N.

The gallium-doped indium-doped single crystal silicon material for solar cells of the present invention is composed of the following components in accordance with the number of atoms per cubic centimeter of single crystal silicon material:

Gallium: 1. O 10 ¹⁴ -1. O 10 ¹⁸ atoms/cm ³

锗: 1. O 10 ¹³ -1. O 10 ¹⁹ atoms/cm ³

Fl: 5.0 10 ¹² -5.0 10 ¹⁶ atoms/cm ³

The rest is monocrystalline silicon. Among them, the purity of gallium, indium and antimony is preferably 5N or 6N. The preparation method used in the present invention is specifically carried out according to the following steps:

1] furnace The furnace can be firstly dismantled and the furnace is cleaned; then the weighed gallium and indium or gallium, germanium and indium are incorporated into the silicon raw material in the quartz crucible, and the quartz crucible and the seed crystal are placed in the single crystal furnace. a magnetic field is arranged outside the single crystal furnace;

When weigh gallium and indium, weigh 1.0x l0 ¹⁴ -1.0x l0 ¹⁸ atoms/cm ³ of gallium, 5.0χ 10 ¹² -5.0χ 10 ¹⁶ atoms/ per cubic centimeter of the number of atoms in the single crystal silicon material. Indium of cm ³ , the rest being silicon raw materials;

Among them, the weighed gallium and indium or gallium, germanium and indium are incorporated into the silicon raw material and incorporated into the silicon germanium silicon raw material. There are two methods:

One is to incorporate gallium and indium or gallium, germanium and indium into the silicon raw material, specifically:

(b then add gallium and indium or gallium, germanium and indium; gallium and indium or gallium, germanium and indium are preferably placed in the central region of the silicon material;

( _Cl ) Finally, the remaining silicon raw material is completely covered on the surface of gallium and indium or gallium, germanium and indium; the other is to prepare a high concentration of gallium-doped, germanium-doped or indium-doped silicon crystal, and then Break separately, then perform the following steps:

(a ₂ ) first layering a silicon material, and the silicon material is spread over the bottom of the quartz crucible;

(b ₂ ) placing a certain amount of high-concentration gallium-doped and indium-doped silicon crystals or gallium-doped, antimony-doped and indium-doped silicon crystals therein; gallium and indium or gallium, germanium and indium are laid with a central region of the silicon raw material Better

(c ₂ ) Finally, the remaining silicon raw material is completely covered on the surface of gallium and indium or gallium, germanium and indium; the magnetic field arranged outside the single crystal furnace is preferably configured: two to many sets of permanent magnets, with a yoke The plates are fixed and evenly distributed around the outside of the single crystal furnace. The magnetic poles are distributed between N and S phases. The magnetic poles of the permanent magnets face the furnace body, and the magnetic strength is 500-3000 GS.

This magnetic field design can increase the viscous force of the silicon melt in the single crystal furnace, suppress the turbulence of the silicon melt, reduce the fluctuation of the temperature of the silicon melt, and the fluctuation of the liquid level. This is very advantageous for growing single crystal silicon for solar cells with low oxygen concentration and uniform distribution in the radial direction, and uniform distribution of gallium indium elements in the radial direction and the axial direction; As shown in Fig. 2, the permanent magnet material a1 and the permanent magnet material c3 are connected by a magnetically conductive soft iron a5, the permanent magnet material b2 and the permanent magnet material d4 are connected by a magnetically conductive soft iron b6, and the permanent magnet connected by the magnetically conductive soft iron a5 The material a1 and the permanent magnet material c3 form a set of permanent magnets, and the permanent magnet material b2 and the permanent magnet material d4 connected by the magnetically conductive soft iron b6 constitute a group of permanent magnets. The two sets of permanent magnets are perpendicular to each other outside the single crystal furnace, and the respective magnetic poles face the single crystal furnace. The two sets of permanent magnets have a square layout outside the circular single crystal furnace;

2] Vacuuming and leak detection

3] Pressure and melt

4] Stabilization

The silicon melt is subjected to a stabilization treatment for 1.5 hours to 2 hours, and the temperature of the silicon melt is stabilized at 1430 ° C to 1470 ° C during the stabilization treatment;

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is 0.5-10r/min, the pressure in the furnace is 1000-2700 Pa, the flow rate of the inert gas is controlled at 10-80 slpm, and the magnetic field strength is 500-3000 GS;

5] seeding

Preheating the seed crystal, welding the preheated seed crystal and the stabilized silicon melt, and then performing a seeding operation; the seeding operation can be performed by a conventional method;

6] After the seeding operation, the shoulder, the shoulder, the equal diameter growth and the finishing are sequentially performed to obtain a single crystal silicon rod; the shoulder, the shoulder, the equal diameter growth and the closing can be carried out by a conventional method;

The parameters for the shoulder are: Pulling speed 0.1-2.0mm/min, where the optimal pulling speed is

0.3-lmm/min, seed crystal speed 1.0-20.0r/min, optimal speed 5.0-15.0r/min;

The parameters of the shoulder: the pulling speed is 2.0-5.0m/min _;

Parameters for equal diameter growth: Pulling speed 0.5-2mm/min, optimum pulling speed 0.7-1.5mm/min, rotation speed of ingot 1.0-20.0r/min, optimal speed of crystal rod 5.0-15.0r/min , the speed of the quartz crucible 0.5-10r/min, the optimum speed of quartz crucible is 4-8r/min, the inert gas flow rate in single crystal furnace is 10-80slpm, the optimal flow rate is 25-60slpm, the pressure in the furnace is 1000-2700 Pa, the optimum pressure in the furnace 1300-2000 Pa, the magnetic field strength outside the single crystal furnace is 500-3000 GS, the distance between the guide tube in the single crystal furnace and the silicon melt is 5.0-30.0 mm;

The closing parameters are: The flow rate of the inert gas in the single crystal furnace is 10-80 slpm, and the optimum flow rate is

20-40slpm, the furnace pressure is 1000-2700 Pa, the optimum pressure in the furnace is 1200-2000 Pa, and the magnetic field strength outside the single crystal furnace is 500-3000 GS. Example 1

1] furnace

The furnace can be firstly dismantled according to the conventional method, and the furnace is cleaned. According to the number of atoms in the cubic silicon material per cubic centimeter, 1.0×10 ¹⁴ atoms/cm ³ of gallium and 5.0×10 ¹² atoms/cm ³ of indium are weighed. In the quartz crucible, the weighed gallium and indium are doped into the silicon raw material, specifically, a silicon raw material is first laid, the silicon raw material is covered with the entire bottom of the quartz crucible; and gallium and indium are placed in the central region of the silicon raw material; Finally, the remaining silicon material is completely covered on the surface of gallium and indium;

The quartz crucible and the seed crystal are placed in a single crystal furnace, and two vertical permanent magnets fixed by the yoke plate are arranged along the two radial directions perpendicular to the single crystal furnace outside the conventional single crystal furnace, and the permanent magnet material is used. The magnetic pole faces the furnace body;

2] Vacuuming and leak detection

3] Pressure and melt

The rotation speed of the quartz crucible is set to 2r/min, the pressure in the furnace is 1000 Pa, the flow rate of the inert gas (argon) is controlled at 10 slpm, and the magnetic field strength is 500 GS. Under the protection of inert gas, the single crystal furnace is pressurized and heated. A silicon melt is obtained.

4] Stabilization

The silicon melt was stabilized for 1.5 hours, and the temperature of the silicon melt was stabilized at 1450 ° C during the stabilization treatment;

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is 2.0 r/min, the pressure in the furnace is 1000 Pa, the flow rate of the inert gas (argon) is controlled at 10 Slpm, and the magnetic field strength is 500 GS; 5] seeding

The seed crystal is preheated for 10 minutes, and the seed crystal preheating height is between 10 and 500 mm. The preheated seed crystal is welded to the stabilized silicon melt, and the seeding operation is performed after 20 minutes of welding; The seeding operation can be carried out by a conventional method;

The parameters of seeding are: quartz crucible rotation speed 0.5r/min, furnace pressure 1000pa, inert gas

The flow rate of (argon) is controlled at 10 slpm, the magnetic field strength is 500 GS, the distance between the guide tube and the silicon melt is 5.0 mm, and the average pulling speed of the seeding is 5-8 mm/min _; the length of the seeding is larger than the diameter of the crystal;

The parameters of the shoulder are: pulling speed 0.1mm/min, seed crystal speed l.Or/min;

The parameters of the shoulder are: pulling speed 5.0mm/min _;

The parameters of equal diameter growth are: pulling speed 2.0mm/min, rotation speed of crystal rod 8.0r/min, rotation speed of quartz crucible 5r/min, flow rate of inert gas (argon gas) in single crystal furnace lOslpm, pressure 1000pa, The magnetic field strength outside the single crystal furnace is 500 GS, the distance between the guide tube in the single crystal furnace and the silicon melt is 5.0 mm _{; the} closing parameters are: the flow rate of the inert gas (argon) in the single crystal furnace is 10 slpm, the optimum flow rate pressure 1000 Pa, the magnetic field strength outside the single crystal furnace is 500 GS, and a single crystal silicon rod having a diameter of 3 inches is obtained by cooling. Example 2

1] furnace

The furnace can be firstly dismantled according to the conventional method, and the furnace is cleaned. According to the number of atoms in the cubic silicon material per cubic centimeter, 1.0×10 ¹⁸ atoms/cm ³ of gallium, 5.0×10 ¹⁶ atoms/cm ³ of indium are weighed. In the quartz crucible, the weighed gallium and indium are doped into the silicon raw material, specifically, a silicon raw material is first laid, the silicon raw material is covered with the entire bottom of the quartz crucible; and gallium and indium are placed in the central region of the silicon raw material; Finally, the remaining silicon material is completely covered on the surface of gallium and indium;

2] Vacuuming and leak detection Vacuuming and leak detection in the single crystal furnace; vacuuming and leak detection can be carried out by conventional methods;

3] Pressure and melt

The speed of the quartz crucible is set to 10r/min, the pressure in the furnace is 1300 Pa, the flow rate of the inert gas (argon) is controlled at 30 slpm, and the magnetic field strength is 1500 GS. Under the protection of inert gas, the single crystal furnace is pressurized and heated. A single crystal silicon melt was obtained.

4] Stabilization

The silicon melt was stabilized for 2 hours, and the temperature of the silicon melt was stabilized at 1430 ° C during the stabilization treatment;

The parameters of the stabilization treatment are: the rotational speed of the quartz crucible is lO.Or/min, the pressure in the furnace is 1300 Pa, the flow rate of the inert gas (argon) is controlled at 25 slpm, and the magnetic field strength is 1500 GS;

5] seeding

The seed crystal is preheated for 60 minutes, and the preheating height of the seed crystal is between 10 and 500 mm. The preheated seed crystal is welded to the stabilized silicon melt, and the seeding operation is performed after 20 minutes of welding; The seeding operation can be carried out by a conventional method;

The parameters of seeding are: quartz crucible rotation speed 1.2r/min, furnace pressure 1300 Pa, inert gas

The flow rate of (argon) is controlled at 25 slpm, the magnetic field strength is 1500 GS, the distance between the guide tube and the silicon melt is 10.0 mm, and the average pulling speed of the seeding is 5-8 mm/min _; the length of the seeding is larger than the diameter of the drawn crystal;

The parameters of the shoulder are: pulling speed 3.0mm/min, seed crystal speed 20.0r/min;

The parameters of the shoulder are: lifting speed 2.5mm/min _;

The parameters of equal diameter growth are: pulling speed l. l lmm/min, rotation speed of ingot 20.0r/min, rotation speed of quartz crucible 10.0r/min, flow rate of inert gas (argon) in single crystal furnace 80slpm, pressure 1300 Pa, the magnetic field strength outside the single crystal furnace is 1500 GS, and the distance between the guide tube in the single crystal furnace and the silicon melt is 10.0 mm;

The closing parameters are: The flow rate of inert gas (argon) in the single crystal furnace is 80 slpm, the pressure is 130 Pa, the magnetic field strength outside the single crystal furnace is 1500 GS, and the single crystal silicon rod with a diameter of 4 inches is obtained by cooling. Example 3 1] furnace

The furnace can be firstly dismantled according to the conventional method, and the furnace is cleaned. Firstly, a high concentration of gallium-doped or indium-doped silicon crystals is separately prepared, and then separately crushed; according to the number of atoms per cubic centimeter of single crystal silicon material, weighed 3.03 x l0 ¹⁵ atoms/cm ³ of gallium, 8.3 x l0 ¹² atoms/cm ³ of indium, and then carry out the following steps: (a ₂ ) first lay a layer of silicon material, and the silicon material fills the entire bottom of the quartz crucible;

(b ₂ ) further placing a certain amount of high-concentration gallium-doped and indium-doped silicon crystals into a central region of the silicon raw material; (c ₂ ) finally completely covering the remaining silicon raw materials on the surfaces of gallium and indium;

2] Vacuuming and leak detection

3] Pressure and melt

Set the quartz crucible to rotate at 0.5r/min, the furnace pressure is 1500 Pa, the inert gas (argon) flow rate is controlled at 30 slpm, and the magnetic field strength is 2500 GS. Under the inert gas protection, the single crystal furnace is pressurized and heated. , to obtain a silicon melt.

4] Stabilization

The silicon melt was stabilized for 1.5 hours, and the temperature of the silicon melt was stabilized at 1440 ° C during the stabilization treatment;

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is 0.5r/min, the pressure in the furnace is 1500 Pa, the flow rate of the inert gas (argon) is controlled at 30 slpm, and the magnetic field strength is 2500 GS;

5] seeding

The seed crystal is preheated for 30 minutes, and the preheating height of the seed crystal is between 10 and 500 mm. The preheated seed crystal is welded to the stabilized silicon melt, and the seeding operation is performed after 20 minutes of welding; The seeding operation can be carried out by a conventional method;

The parameters of seeding are: quartz crucible speed 6.0r/min, furnace pressure 1500pa, inert gas (argon) flow rate controlled at 30slpm, magnetic field strength 2500GS, guide tube distance from silicon melt 10.0mm, The average pulling speed of the crystal is 5-8 mm/min _; the length of the seeding is larger than the diameter of the drawn crystal; 6] After the seeding operation, the shoulder, the shoulder, the equal diameter growth and the finishing are sequentially performed to obtain a single crystal silicon rod; the shoulder, the shoulder, the equal diameter growth and the closing can be carried out by a conventional method;

The parameters of the shoulder are: pulling speed 2.0mm/min, seed crystal speed 12.0r/min _;

The parameters of the shoulder are: pulling speed 1.0mm/min _;

The parameters of equal diameter growth are: pulling speed 1.04mm/min, rotation speed of crystal rod 12.0r/min, rotation speed of quartz crucible 10.0r/min, flow rate of inert gas (argon) in single crystal furnace 40slpm, pressure 2000 Pa The magnetic field strength outside the single crystal furnace is 1500 GS, and the distance between the guide tube in the single crystal furnace and the silicon melt is 10.0 mm;

The closing parameters are as follows: The flow rate of inert gas (argon) in the single crystal furnace is 30 slpm, the pressure is 1500 Pa, the magnetic field strength outside the single crystal furnace is 1500 GS, and the single crystal silicon rod with a diameter of 6 inches is obtained by cooling. Example 4

1] furnace

The furnace can be firstly dismantled according to the conventional method, and the furnace is cleaned. Firstly, a high concentration of gallium-doped or indium-doped silicon crystals is separately prepared, and then separately crushed; according to the number of atoms per cubic centimeter of single crystal silicon material, weighed l. lx l0 ¹⁶ atoms/cm ³ of gallium, 2.3 x l0 ¹² atoms/cm ³ of indium, then perform the following steps:

(b ₂ ) further placing a certain amount of high-concentration gallium-doped and indium-doped silicon crystals into a central region of the silicon raw material;

(c ₂ ) finally completely covering the surface of the gallium and indium with the remaining silicon material;

2] Vacuuming and leak detection

3] Pressure and melt

The speed of the quartz crucible is set to 1.0r/min, the pressure in the furnace is 2700 Pa, the flow rate of the inert gas (argon) is controlled at 80 slpm, and the magnetic field strength is 3000 GS. Under the protection of inert gas, the single crystal furnace is pressurized and heated. , to obtain a silicon melt.

4] Stabilization The silicon melt was stabilized for 2.0 hours, and the temperature of the silicon melt was stabilized at 1470 ° C during the stabilization treatment;

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is l.Or/min, the pressure in the furnace is 2700 Pa, the flow rate of the inert gas (argon) is controlled at 80 slpm, and the magnetic field strength is 3000 GS;

5] seeding

The seed crystal is preheated for 60 minutes, and the preheating height of the seed crystal is between 10 and 500 mm. The preheated seed crystal is welded to the stabilized silicon melt, and the seeding operation is performed after 30 minutes of welding; The seeding operation can be carried out by a conventional method;

The parameters of seeding are: the rotation speed of quartz crucible is 10.O/min, the pressure in the furnace is 2700 Pa, the flow rate of inert gas (argon) is controlled at 35 slpm, the magnetic field strength is 3000 GS, and the distance between the guide tube and the silicon melt is 10.0 mm. The average pulling speed of the seeding is 5-8mm/min _; the length of the seeding is larger than the diameter of the crystal; after the seeding operation, the shoulder, the shoulder, the equal diameter growth and the finishing are sequentially performed to obtain a single crystal silicon rod; Shoulder, shoulder, equal diameter growth and finishing can be carried out by conventional methods;

The parameters of the shoulder are: pulling speed 1.0mm/min, seed crystal speed 10.0r/min;

The parameters of the shoulder are: lifting speed 4.0mm/min _;

The parameters of equal diameter growth are: pulling speed 0.5mm/min, rotation speed of crystal rod 1.0r/min, rotation speed of quartz crucible 10.0r/min, flow rate of inert gas (argon) in single crystal furnace 60slpm, pressure 2200 Pa The magnetic field strength outside the single crystal furnace is 3000 GS, and the distance between the guide tube in the single crystal furnace and the silicon melt is 30.0 mm;

The closing parameters are: The flow rate of inert gas (argon) in the single crystal furnace is 50slpm, the pressure is 2100 Pa, the magnetic field strength outside the single crystal furnace is 3000GS, and the single crystal silicon rod with a diameter of 8 inches is obtained by cooling.

Table 1 shows the product parameters of a 3 inch, 4 inch, 6 inch, 8 inch gallium-doped indium single crystal silicon rod prepared in Example 1, Example 2, Example 3 and Example 4. Products with 3 inch, 4 inch, 6 inch, 8 inch gallium-doped indium single crystal silicon rods

The data shown in Table 1 shows that the gallium-doped indium single crystal silicon for solar energy mentioned in the present invention can be produced by the preparation method of the present invention. The gallium-doped indium single crystal silicon mentioned in the present invention, regardless of the diameter and size of the single crystal silicon rod, has: (1) a conversion efficiency exceeding 17%, and a low light decay rate; (2) oxygen in single crystal silicon The content is low and uniform in the radial direction of the single crystal silicon rod; this is very advantageous for low-cost, high-efficiency production of various types of solar cells. Example 5

1] furnace

The furnace can be removed according to the conventional method, and the furnace is cleaned. According to the number of atoms in the cubic silicon material per cubic centimeter, 1.0 l0 ¹⁴ atoms/cm ³ of gallium is weighed, 1.0 l0 ¹³ atoms/cm ³ of 锗, 5.0 Xl 0 ¹² atoms/cm ³ of indium, in the quartz crucible, the weighed gallium, germanium and indium are incorporated into the silicon raw material, specifically by first laying a layer of silicon raw material, and the silicon raw material is covered with the entire bottom of the quartz crucible; The central region of the silicon raw material is filled with gallium, germanium and indium; finally, the remaining silicon raw material is completely covered on the surfaces of gallium, germanium and indium; the quartz crucible and the seed crystal are placed in a single crystal furnace, and in a conventional single crystal furnace In addition, two vertical permanent magnets fixed by a yoke plate are arranged along two radial directions perpendicular to the phase of the single crystal furnace, and the magnetic poles of the permanent magnet material face the furnace body; 2] Vacuuming and leak detection

3] Pressure and melt

The quartz crucible is set to rotate at 3.0r/min, the furnace pressure is 1300 Pa, the inert gas (argon) flow rate is controlled at 25 slpm, and the magnetic field strength is 500 GS. Under the protection of inert gas, the single crystal furnace is pressurized and heated. , to obtain a silicon melt.

4] Stabilization

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is 5.0r/min, the pressure in the furnace is 1300 Pa, the flow rate of the inert gas (argon) is controlled at 25 slpm, and the magnetic field strength is 500 GS;

5] seeding

The seed crystal is preheated for 20 minutes, and the seed crystal preheating height is between 10 and 500 mm. The preheated seed crystal is welded to the stabilized silicon melt, and the seeding operation is performed after 20 minutes of welding; The seeding operation can be carried out by a conventional method;

The parameters of seeding are: quartz crucible speed 3.0r/min, furnace pressure 1300 Pa, inert gas (argon) flow rate controlled at 25 slpm, magnetic field strength 500 GS, guide tube distance from silicon melt 10.0 mm, The average pulling speed of the crystal is l-8mm/min _; the length of the seeding is larger than the diameter of the crystal to be pulled; 6] After the seeding operation, the shoulder, the shoulder, the equal diameter growth and the finishing are sequentially performed to obtain a single crystal silicon rod. Shoulder, shoulder, equal diameter growth and closing can be carried out by conventional methods;

The parameters of the shoulder are: pulling speed 0.6mm/min, seed crystal speed 8.0r/min _;

The parameters of the shoulder are: pulling speed 3.0mm/min _;

The parameters of equal diameter growth are: pulling speed 2.0mm/min, rotation speed of crystal rod 15.0r/min, rotation speed of quartz crucible 10r/min, flow rate of inert gas (argon) in single crystal furnace 20slpm, pressure 1000pa, The magnetic field strength outside the single crystal furnace is 500 GS, and the distance between the guide tube in the single crystal furnace and the silicon melt is 10.0 mm;

The closing parameters are: The flow rate of inert gas (argon) in the single crystal furnace is 10 slpm, the pressure is 1000 Pa, the magnetic field strength outside the single crystal furnace is 500 GS, and the single crystal silicon rod with a diameter of 3 inches is obtained by cooling. Example 6

1] furnace

The furnace can be removed according to the conventional method, and the furnace is cleaned. According to the number of atoms in the cubic silicon material per cubic centimeter, 1.0 l0 ¹⁸ atoms/cm ³ of gallium is weighed, 1.0 l0 ¹⁸ atoms/cm ³ of 锗, 5.0 Xl 0 ¹⁶ atoms/cm ³ of indium, in the quartz crucible, the weighed gallium, germanium and indium are incorporated into the silicon raw material, specifically by first laying a layer of silicon raw material, and the silicon raw material is covered with the entire bottom of the quartz crucible; The central region of the silicon raw material is filled with gallium, germanium and indium; finally, the remaining silicon raw material is completely covered on the surfaces of gallium, germanium and indium; the quartz crucible and the seed crystal are placed in a single crystal furnace, and in a conventional single crystal furnace In addition, two vertical permanent magnets fixed by a yoke plate are arranged along two radial directions perpendicular to the phase of the single crystal furnace, and the magnetic poles of the permanent magnet material face the furnace body;

2] Vacuuming and leak detection

3] Pressure and melt

The speed of the quartz crucible is set to 10.0r/min, the pressure in the furnace is 1300 Pa, the flow rate of the inert gas (argon) is controlled at 25 slpm, and the magnetic field strength is 1500 GS. Under the protection of inert gas, the single crystal furnace is pressurized and heated. , to obtain a silicon melt.

4] Stabilization

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is 10.0r/min, the pressure in the furnace is 1300 Pa, the flow rate of the inert gas (argon) is controlled at 30 slpm, and the magnetic field strength is 1500 GS;

5] seeding

The parameters of seeding are: quartz crucible rotation speed 2.0r/min, furnace pressure 2100 Pa, inert gas (argon) flow rate controlled at 50 slpm, magnetic field strength 1500 GS, guide tube distance from silicon melt 10.0 mm, The average pulling speed of the crystal is 5-8 mm/min _; the length of the seeding is larger than the diameter of the drawn crystal; 6] After the seeding operation, the shoulder, the shoulder, the equal diameter growth and the finishing are sequentially performed to obtain a single crystal silicon rod; the shoulder, the shoulder, the equal diameter growth and the closing can be carried out by a conventional method;

The parameters of the shoulder are: pulling speed 1.0mm/min, seed crystal speed 20.0r/min _;

The parameters of the shoulder are: lifting speed 2.5mm/min _;

The parameters of equal diameter growth are: pulling speed l. l lmm/min, rotation speed of crystal rod 20r/min, rotation speed of quartz crucible 10.0r/min, flow rate of inert gas (argon gas) in single crystal furnace 80slpm, pressure 2700 Pa, the magnetic field strength outside the single crystal furnace is 1500 GS, and the distance between the guide tube in the single crystal furnace and the silicon melt is 10.0 mm;

The closing parameters are: The flow rate of inert gas (argon) in the single crystal furnace is 80slpm, the pressure is 2700 Pa, the magnetic field strength outside the single crystal furnace is 1500 GS, and the single crystal silicon rod with a diameter of 4 inches is obtained by cooling. Example 7

1] furnace

The furnace may be firstly dismantled according to a conventional method, and the furnace is cleaned to prepare a high concentration of gallium-doped, erbium-doped or indium-doped silicon crystals, and then separately crushed; according to the number of atoms in each cubic centimeter of single crystal silicon material, Weigh 3.03 x l0 ¹⁵ atoms/cm ³ of gallium, 5.0x l0 ¹⁷ atoms/cm ³ of 锗,

8.3 l 0 ¹² atoms/cm ³ of indium, then perform the following steps:

(b ₂ ) further placing a certain amount of high-concentration gallium-doped, antimony-doped and indium-doped silicon crystals into a central region of the silicon raw material;

( ) Finally, the remaining silicon material is completely covered on the surface of gallium, germanium and indium;

2] Vacuuming and leak detection

3] Pressure and melt The speed of the quartz crucible is set to 0.5r/min, the pressure in the furnace is 1300 Pa, the flow rate of the inert gas (argon) is controlled at 25 slpm, and the magnetic field strength is 2500 GS. Under the protection of inert gas, the single crystal furnace is pressurized and heated. , to obtain a silicon melt.

4] Stabilization

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is 0.5r/min, the pressure in the furnace is 1300 Pa, the flow rate of the inert gas (argon) is controlled at 25 slpm, and the magnetic field strength is 2500 GS;

5] seeding

The parameters of seeding are: quartz crucible speed 6.0r/min, furnace pressure 2000pa, inert gas (argon) flow rate controlled at 20slpm, magnetic field strength 2500GS, guide tube distance from silicon melt 10.0mm, The average pulling speed of the crystal is l-8 mm/min _; the length of the seeding is larger than the diameter of the drawn crystal;

6] After the seeding operation, the shoulder treatment, the shoulder treatment, the equal diameter growth treatment and the finishing treatment are sequentially performed to obtain a single crystal silicon rod; the shoulder, the shoulder, the equal diameter growth and the closing can be carried out by a conventional method; The parameters of the shoulder are: pulling speed 2.0mm/min, seed crystal speed 12.0r/min _;

The parameters of the shoulder are: pulling speed 1.0mm/min _;

The parameters of equal diameter growth are: pulling speed 1.04mm/min, rotation speed of crystal rod 12.0r/min, rotation speed of quartz crucible 8.0r/min, inert gas in argon furnace (argon) flow rate 40 slpm, pressure 2000 Pa, the magnetic field strength outside the single crystal furnace is 2500 GS, and the distance between the guide tube in the single crystal furnace and the silicon melt is 10.0 mm;

The closing parameters are: The flow rate of inert gas (argon) in the single crystal furnace is 25slpm, the pressure is 1300 Pa, the magnetic field strength outside the single crystal furnace is 2500 GS, and the single crystal silicon rod with a diameter of 6 inches is obtained by cooling. Example 8

1] furnace The furnace may be firstly dismantled according to a conventional method, and the furnace is cleaned to prepare a high concentration of gallium-doped, erbium-doped or indium-doped silicon crystals, and then separately crushed; according to the number of atoms in each cubic centimeter of single crystal silicon material, Weigh l. lx l0 ¹⁶ atoms/cm ³ of gallium, 1.0 x 10 ¹⁶ atoms/cm ³ of yttrium, 2.3 l 0 ¹² atoms/cm ³ of indium, and then perform the following steps:

2] Vacuuming and leak detection

3] Pressure and melt

Set the quartz crucible to rotate at 1.0r/min, the furnace pressure is 2100 Pa, the inert gas (argon) flow rate is controlled at 50 slpm, and the magnetic field strength is 3000 GS. Under the inert gas protection, the single crystal furnace is pressurized and heated. , to obtain a silicon melt.

4] Stabilization

The silicon melt was stabilized for 2 hours, and the temperature of the silicon melt was stabilized at 1470 ° C during the stabilization treatment;

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is l.Or/min, the pressure in the furnace is 2100 Pa, the flow rate of the inert gas (argon) is controlled at 50 slpm, and the magnetic field strength is 3000 GS;

5] seeding

The parameters of seeding are: the rotation speed of quartz crucible is 10.0r/min, the pressure in the furnace is 1800 Pa, the flow rate of inert gas (argon) is controlled at 50 slpm, the magnetic field strength is 3000 GS, and the distance between the guide tube and the silicon melt is 20.0 mm. The average pulling speed of the crystal is l-8 mm/min _; the length of the seeding is larger than the diameter of the drawn crystal; 6] After the seeding operation, the shoulder, the shoulder, the equal diameter growth and the finishing are sequentially performed to obtain a single crystal silicon rod; the shoulder, the shoulder, the equal diameter growth and the closing can be carried out by a conventional method;

The parameters of the shoulder are: pulling speed 4.5mm/min _;

The parameters of equal diameter growth are: pulling speed 0.7mm/min, rotation speed of crystal rod 1.0r/min, rotation speed of quartz crucible 10.0r/min, flow rate of inert gas (argon) in single crystal furnace 60slpm, pressure 2700 Pa The magnetic field strength outside the single crystal furnace is 3000 GS, and the distance between the guide tube in the single crystal furnace and the silicon melt is 30.0 mm;

The closing parameters are: The flow rate of the inert gas (argon) in the single crystal furnace is 50slpm, the optimum flow rate is 2100 Pa, the magnetic field strength outside the single crystal furnace is 3000 GS, and the single crystal silicon rod with a diameter of 8 inches is obtained by cooling.

2 is a product parameter of a 3 inch, 4 inch, 6 inch, 8 inch doped gallium germanium indium single crystal silicon rod prepared in Example 5, Example 6, Example 7 and Example 8,

Table 2 Products of 3 inch, 4 inch, 6 inch, 8 inch gallium-doped indium single crystal silicon rods

The data shown in Table 2 shows that the gallium-doped indium-doped single crystal silicon for solar energy mentioned in the present invention can be produced by the preparation method of the present invention. The gallium-doped indium-doped single crystal silicon mentioned in the present invention, regardless of the diameter and size of the single crystal silicon rod, has: (1) a conversion efficiency exceeding 17%, and a low light decay rate; (2) in single crystal silicon The oxygen content is low, and the radial distribution of the single crystal silicon rod is uniform, and the minority carrier life is improved; this is very advantageous for low-cost, high-efficiency production of various types of solar cells.

Claims

claims

1. A gallium-indium-doped or gallium-germanium-indium-doped single crystal silicon material for solar cells, which is characterized in that it consists of the following components according to the number of atoms per cubic centimeter of the single crystal silicon material:

Gallium: 1. O 10 ¹⁴ -1. O 10 ¹⁸ atoms/cm ³

Indium: 5·0χ10 ¹² -5·0χ10 ¹⁶ atoms/cm ³

The rest is single crystal silicon.

2. The gallium-doped indium or gallium-doped germanium indium single crystal silicon material for solar cells according to claim 1, characterized in that the purity of the gallium and indium is 5N or 6N.

3. A gallium-indium-doped or gallium-germanium-indium-doped single crystal silicon material for solar cells, which is characterized in that it consists of the following components according to the number of atoms per cubic centimeter of the single crystal silicon material:

Gallium: 1. O 10 ¹⁴ -1. O 10 ¹⁸ atoms/cm ³

Germanium: 1. O 10 ¹³ -1. O 10 ¹⁹ atoms/cm ³

fl: 5.0 10 ¹² -5.0 10 ¹⁶ atoms/cm ³

The rest is single crystal silicon.

4. The gallium-doped indium or gallium-doped germanium indium single crystal silicon material for solar cells according to claim 3, characterized in that the purity of the gallium, indium and germanium is 5N or 6N.

5. A method for preparing the gallium-doped indium or gallium-doped germanium indium single crystal silicon material for solar cells according to any one of claims 1 to 4, which mainly includes the following steps:

1] Install furnace

Mix the weighed gallium and indium or gallium, germanium and indium into the silicon raw material in the quartz crucible, place the quartz crucible and the seed crystal into the single crystal furnace, and a magnetic field is arranged outside the single crystal furnace;

When weighing gallium and indium, according to the number of atoms per cubic centimeter of single crystal silicon material, weigh 1.0xl0 ¹⁴ -1.0xl0 ¹⁸ atoms/cm ³ for gallium and 5.0χ10 ¹² -5.0χ10 ¹⁶ atoms/cm ³ for indium. , the rest are single crystal stones;

When weighing gallium, germanium and indium, weigh according to the number of atoms per cubic centimeter of single crystal silicon material.

1.0xl0 ¹⁴ -1.0xl0 ¹⁸ atoms/cm ³ of gallium, 1.0xl0 ¹³ -1.0xl0 ¹⁹ atoms/cm ³ of germanium,

5.0χ10 ¹² -5.0χ10 ¹⁶ atoms/cm ³ of indium, the rest is single crystal silicon;

2] Vacuuming and leak detection

Carry out vacuuming and leak detection in the single crystal furnace; 3] Pressure and melt

Under the protection of inert gas, pressurize and heat the single crystal furnace to obtain silicon melt;

4] Stabilization

Perform a stabilization treatment on the silicon melt for 1.5 hours -2 hours. During the stabilization treatment, the temperature of the silicon melt should be stabilized at 1430°C-1470°C;

The parameters of the stabilization treatment are: the rotation speed of the quartz crucible is 0.5-10 rpm, the pressure in the furnace is 1000-2700 Pa, the flow rate of the inert gas is controlled at 10-80slpm, and the magnetic field strength is 500-3000GS;

5] Seeding

Preheat the seed crystal, weld the preheated seed crystal to the stabilized silicon melt, and then perform the seeding operation;

The seeding parameters are: quartz crucible rotation speed 0.5-10r/min, furnace pressure 1000-2700 Pa, inert gas flow rate controlled at 10-80slpm, magnetic field strength 500-3000GS, and the distance between the guide tube and the silicon melt is 5.0 -30.0mm, the average pulling speed of seeding is l-8mm/min;

6] After the seeding operation, perform shouldering, shouldering, equal diameter growth and finishing in sequence to obtain a single crystal silicon rod; the parameters of shouldering are: pulling speed 0.1-2.0mm/min, seed crystal rotation speed 1.0-20.0r /min, the parameters of shoulder rotation are: shoulder rotation speed 2.0-5.0mm/min;

The parameters of equal diameter growth are: pulling speed 0.5-2mm/min, crystal rod rotation speed 1.0-20.0 rpm, quartz crucible rotation speed 0.5-10 rpm, inert gas flow rate in the single crystal furnace 10-80slpm, The pressure inside the furnace is 1000-2700 Pa, the magnetic field strength outside the single crystal furnace is 500-3000GS, and the distance between the guide tube in the single crystal furnace and the silicon melt is 5.0-30.0mm;

The final parameters are: the flow rate of the inert gas in the single crystal furnace is 10-80slpm, the pressure is 1000-2700 Pa, and the magnetic field strength outside the single crystal furnace is 500-3000GS.

6. The preparation method of gallium-doped indium or gallium-doped germanium indium single crystal silicon material for solar cells according to claim 5, characterized in that: in step 1], gallium and indium or gallium, germanium and indium are mixed The specific silicon raw materials are:

First, lay a layer of silicon raw material so that the silicon raw material covers the entire bottom of the quartz crucible;

(bi:) Then add gallium and indium or gallium, germanium and indium;

( _Cl ) Finally, the remaining silicon raw material is completely covered on the surface of gallium and indium or gallium, germanium and indium.

7. The preparation method of gallium-doped indium or gallium-doped germanium indium single crystal silicon material for solar cells according to claim 5, characterized in that: in the step 1], gallium and indium or gallium, germanium and indium are doped. Into the silicon raw material, specifically, first prepare high-concentration gallium-doped, germanium-doped, or indium-doped silicon crystals, then crush them respectively, and then perform the following steps:

(a ₂ ) First lay a layer of silicon raw material so that the silicon raw material covers the entire bottom of the quartz crucible;

(b ₂ ) Then put a certain amount of high-concentration gallium-doped and indium-doped silicon crystals or gallium-doped, germanium-doped, and indium-doped silicon crystals into it;

(c ₂ ) Finally, the remaining silicon raw material is completely covered on the surface of gallium and indium or gallium, germanium and indium.

8. The method for preparing gallium-doped indium or gallium-doped germanium indium single crystal silicon material for solar cells according to any one of claims 5 to 7, characterized in that: in step 1], the magnetic field outside the single crystal furnace is It consists of two or more sets of permanent magnets, fixed with yoke plates, evenly distributed around the outside of the single crystal furnace. The magnetic poles are distributed in N and S phases. The magnetic poles of the permanent magnets face the furnace body, and the magnetic strength is 500-3000GS.

9. The preparation method of gallium-doped indium or gallium-doped germanium indium single crystal silicon material for solar cells according to claim 8, characterized in that: in step 0, gallium and indium or gallium, germanium and indium are laid, or In step (b ₂ ), the high-concentration gallium-doped and indium-doped silicon crystals or the gallium-, germanium-, and indium-doped silicon crystals are laid in the central area of the silicon raw material.

10. The method for preparing gallium-doped indium or gallium-doped germanium indium single crystal silicon material for solar cells according to claim 8, characterized in that: the seed crystal preheating is to preheat the seed crystal height, The crystal preheating height is 10-500mm, and the preheating time is 10-60 minutes; in the step 5] seeding, the rotation speed of the quartz crucible is 3-7r/min, the pressure in the furnace is 1200-2000 Pa, and the inert gas is The flow rate is controlled at 20-40slpm _; in the step 6], the pulling speed of the shoulder-laying treatment is 0.3-1mm/min, the seed crystal rotation speed is 5.0-15.0r/min; the pulling speed of the equal-diameter growth is 0.7-1.5 mm/min, the rotation speed of the crystal rod is 5.0-15.0r/min, the rotation speed of the quartz crucible is 4-8 rpm, the flow rate of inert gas in the single crystal furnace is 25-60slpm, and the pressure in the furnace is 1300-2200 Pa; At the end, the flow rate of the inert gas in the single crystal furnace is 20-40slpm, and the pressure in the furnace is 1200-2000 Pa.