JPH11292693A - Liquid crystal growth method of silicon crystal, method of manufacturing solar cell, and liquid phase growth apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal growth method of a silicon crystal capable of continuous growth and high mass productivity and a method of manufacturing a solar cell. SOLUTION: A raw material gas containing at least silicon atoms is blown into a solvent to decompose the raw material gas and at the same time dissolve the silicon atoms in the solvent to supply silicon atoms into the solvent, and immerse the substrate in the solvent or A liquid crystal growth method for a silicon crystal characterized by growing a silicon crystal on the substrate by contacting the same, and a method for manufacturing a solar cell using the same. Further, the present invention provides a liquid crystal growth apparatus for silicon crystal having means for blowing a source gas containing at least silicon atoms into a solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal growth method for a silicon crystal, a method for manufacturing a solar cell, and a liquid phase growth apparatus.
In particular, it relates to a liquid phase growth method capable of continuous growth and mass production.

[0002]

2. Description of the Related Art The liquid phase growth method has the advantage that a crystal of good quality close to the stoichiometric composition can be obtained because the crystal is grown from a quasi-equilibrium state. Used in the production of LEDs (light emitting diodes) and laser diodes. Recently, liquid phase growth of Si has been attempted for the purpose of obtaining a thick film (for example, see Japanese Patent Application Laid-Open No. 58-898).
No. 74), and application to solar cells is also being studied.

In the conventional liquid phase growth method, a solution containing a substance for growth as a solute is generally cooled to a supersaturated state,
Excess solute (a substance for growth) is deposited on the substrate. Prior to depositing (growing) the solute on the substrate,
It is necessary to dissolve the solute in the solvent until it is saturated. Usually, a method of dissolving a solute in a solvent includes a method in which an amount of the solute that is saturated at a temperature at which the solute is saturated is mixed with the solvent and heating, and a method in which a large amount of the solute is contained in the solvent (more than a saturated amount). May be heated in a state of contact with the solution, and may be saturated by maintaining the melting temperature. In the former case, a newly weighed solute is added to the solvent every time the growth is completed, or replaced with another solvent in which the solvent has been dissolved. In the latter, the base material that becomes a solute is moved in and out of the solvent before or after growth.However, since the base material is consumed and troubles occur at the end, or the amount of melt-in becomes insufficient, a new material is used. It needs to be replaced with a suitable base material. In any case, when the material is exhausted, the apparatus is stopped for replenishment, or the growth is interrupted, so that a time loss occurs. Thus, the method according to the prior art has a problem in terms of mass productivity.

[0004]

SUMMARY OF THE INVENTION The present invention has been completed as a result of intensive studies by the present inventors in order to solve the above-mentioned problems in the prior art, and is a simple and highly mass-produced liquid phase growth method. The purpose is to provide.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a method and a method for blowing a source gas containing at least silicon atoms into a solvent to decompose the source gas and dissolve the silicon atoms in the solvent at the same time. And growing the silicon crystal on the substrate by immersing or contacting the substrate in the solvent to provide a liquid crystal growth method of the silicon crystal.

Further, the present invention is directed to a method for manufacturing a solar cell, comprising at least a step of forming a silicon layer by liquid phase growth. Supplying silicon atoms in the solvent by dissolving the solvent in the solvent, and immersing or contacting the substrate in the solvent, thereby growing the silicon crystal on the substrate to form the silicon layer. And a method for manufacturing a solar cell.

Further, the present invention provides a liquid crystal growth apparatus for silicon crystal, comprising: means for holding a solvent for dissolving silicon atoms; and means for immersing or contacting a substrate in the solvent. The present invention provides a liquid crystal growth apparatus for a silicon crystal, comprising means for blowing a source gas containing

Further, the present invention provides a solvent reservoir for holding a solvent for dissolving silicon atoms, a source gas inlet tube having an opening in the solvent held in the solvent reservoir, and a wafer cassette for holding a substrate. A liquid crystal growth apparatus for a silicon crystal, comprising: a wafer cassette capable of being taken in and out of a solvent held in the solvent reservoir; and a heater.

Further, the present invention provides a solvent reservoir and a growth tank for holding a solvent for dissolving silicon atoms, a pipe for circulating the solvent between the solvent reservoir and the growth tank, A source gas introduction pipe having an opening in a solvent held in the wafer, a wafer cassette holding a substrate, a wafer cassette capable of being taken in and out of the solvent held in the growth tank, and a heater. The present invention provides a liquid crystal growth apparatus for a silicon crystal characterized by the following.

[0010] In addition, the present invention provides a solvent reservoir for holding a solvent that dissolves silicon atoms, a pipe having both ends connected to the solvent reservoir and having openings other than both ends for circulating the solvent, A source gas introduction pipe having an opening in the solvent held in the solvent reservoir, a holding member for holding the substrate such that the substrate is in contact with the solvent at the opening, and a heater;
A liquid crystal growth apparatus for a silicon crystal, comprising:

[0011]

FIG. 1 shows an example of a liquid phase growth apparatus used in the liquid phase growth method of the present invention. In FIG.
Is a wafer cassette, 102 is a substrate (wafer), 103 is a solvent reservoir (crucible), 104 is a solvent (melt), 105 is a reaction product gas, 106 is a source gas introduction tube, 107 is a reaction tube, and 108 is an electric furnace (heater). ).

Reference numeral 109 denotes a gas blowing hole provided in the source gas introduction pipe, 110 denotes a gate valve, and 111 denotes a gate valve.
Is an exhaust port.

A liquid phase growth method and a liquid phase growth apparatus according to the present invention will be described below with reference to FIG. As shown in FIG. 1, a carbon solvent reservoir (crucible) 103 is filled with a solvent 104 made of a metal (hereinafter referred to as a metal solvent), and is supplied along a side wall and a bottom surface of the crucible 103 for introducing a source gas. A tube 106 is provided. Above the crucible 103, a wafer cassette 101 loaded with wafers 102
The wafer 102 is immersed in the metal solvent 104 by moving up and down, or the wafer 102 is pulled up from the metal solvent 104 to perform the growth start processing / growth end processing. Further, the wafer cassette 101 is also provided with a rotation mechanism, and by rotating the wafer cassette 101 during growth, the grown film thickness can be made uniform within the wafer surface and between the wafers. The crucible 103, the source gas introduction tube 106, and the wafer cassette 101 are
7 and heated by an electric furnace 108 disposed outside the reaction tube 107.

Hereinafter, the specific procedure of the liquid phase growth method of the present invention will be described. First, the non-saturated or post-growth metal solvent 104 is heated to a predetermined temperature (slightly higher than the growth temperature), and waits until it is stabilized. Next, a raw material gas, for example, SiH ₄ is supplied to the raw gas introduction pipe 106 as a supply source of Si, and the raw material gas (SiH ₄ ) is supplied from a gas blowing hole 109 opened on the surface of the introduction pipe arranged on the bottom of the crucible. It is jetted into the metal solvent to bring the source gas (SiH ₄ ) into contact with the metal solvent. If a raw material gas using SiH _4, SiH ₄ in contact with the metal solvent is decomposed into Si atoms and H ₂ molecules to immediately react, Si atoms are dissolved in the metal solvent. At this time,
The generated H ₂ molecules stir the metal solvent to promote the dissolution of the Si atoms in the solvent, but it is also possible to provide a separate stirring mechanism (not shown) for positive stirring. After blowing out the SiH ₄ gas into the metal solvent for a certain time, the SiH ₄ gas is stopped and the electric furnace 108 is controlled to perform slow cooling. When the temperature reaches the growth start temperature, the wafer cassette 101 is lowered to immerse the wafer 102 in the metal solvent 104. It is preferable that the wafer cassette 101 be rotated at a speed of several rpm during the growth to make the grown film thickness uniform. After a predetermined growth time, the wafer cassette 101 is pulled up from the metal solvent 104, and the growth is completed. In this example, the wafer 102
Are arranged with a certain inclination in the wafer cassette 101, so that the metal solvent 104 hardly remains on the wafer surface when the wafer 102 is pulled up from the metal solvent 104, but the wafer 102 and the wafer cassette 101 slightly contact each other. The metal solvent may remain in the portion (supporting portion). In such a case, the remaining metal solvent can be shaken off by rotating the wafer cassette at a rotation speed of several tens of rpm or more. Subsequently, the wafer cassette is pulled up to a preparatory chamber (not shown) separate from the reaction tube, and the wafer is exchanged. By repeating the above-described steps, liquid phase growth can be performed continuously.

The feature of the present invention is that the raw material gas and the metal solvent are brought into contact with each other so that the raw material can be continuously supplied into the solvent. Can increase the quality.

As a material of a solvent reservoir for containing a metal solvent used in the present invention and a material of a wafer cassette for supporting a wafer, mainly high-purity carbon or high-purity quartz is preferably used. Similarly, high-purity carbon or high-purity quartz or the like is suitably used as the material of the raw material gas introduction tube used in the present invention, and high-purity quartz is suitably used as the material of the reaction tube. The source gases used include silanes such as SiH ₄ , Si ₂ H ₆ ,... Si _n H _{2n + 2} (n: natural number) and SiH ₂ Cl ₂ , SiHCl ₃ , SiCl ₄ , SiH ₂ F ₂ , Si ₂ halogenated silanes such as F ₆ can be mentioned as preferred.

It is preferable to add the above-mentioned source gas hydrogen (H ₂ ) as a carrier gas or for the purpose of obtaining a reducing atmosphere for promoting crystal growth. The ratio of the amounts of the source gas and hydrogen is determined as appropriate depending on the forming method, the type of the source gas, and the forming conditions, and is preferably 1: 1000 or more and 100: 1 or less (introduction flow ratio), and more preferably 1: 100 or more. Ten:
More preferably, it is set to 1 or less.

The solvent used in the present invention is In, Sn,
Solvents composed of metals such as Bi, Ga, and Sb are suitable. Epitaxial growth is performed by bringing the source gas into contact with the solvent to dissolve the Si atoms and then gradually cooling the solvent, or by providing a temperature difference between the solvents while supplying Si atoms to the solvent with the source gas.

The temperature and pressure in the liquid phase growth method used in the present invention vary depending on the forming method and the kind of the raw material (gas) used.
600 ° C or higher when growing silicon using n, In
It is desirable to control the temperature of the solvent below 050 ° C. The pressure is generally in the range of 10 ^-2 Torr to 760 Torr, and more preferably in the range of 10 ^-1 Torr to 760 Torr.

If it is necessary to control the conductivity type (p-type / n-type) of Si, a gas containing a dopant such as P or B may be appropriately introduced into the solvent. Also, a method of growing a silicon crystal using indium as a solvent without adding a dopant to form a silicon layer, and then diffusing the dopant into a part of the silicon layer by a method such as thermal diffusion or ion implantation. By forming an n-type layer, a solar cell element can be formed.

[0021]

EXAMPLES Hereinafter, the growth of a desired crystal by the method of the present invention will be described in more detail with reference to Examples.
The present invention is not limited by these examples.

Example 1 In this example, an Si epitaxial layer was grown using a liquid phase growth apparatus having the structure shown in FIG. In for solvent, Si for source gas
The H ₄ was used. In a state in which five 5 ″ Si wafers 102 are placed and the wafer cassette 101 is kept in a standby chamber (not shown), the solvent reservoir 103 containing the In solvent 104 is heated by the heater 10.
8 and the temperature of the solvent was kept constant at 960 ° C. Note that 5 ″ means that the diameter of the wafer is 5 inches.
01 was introduced into the reaction tube 107 by opening the gate valve 110, and was held immediately above the solvent reservoir 103. The gate valve was kept open thereafter. The source gas SiH ₄ was spouted together with the H ₂ gas (gas flow ratio SiH ₄ / H ₂ = 1: 1) through the source gas inlet tube 106 into the In solvent 104, and these gases were kept flowing for 30 minutes. After the flow of the gas is completed, the heater 108 is controlled to gradually cool the solvent in the reaction tube 107 at a rate of -1 ° C / min. When the temperature of the In solvent 104 reaches 950 ° C, the wafer cassette 101 is rotated at 10 rpm. The wafer cassette 101 is lowered into the In solvent 104 while being rotated at a rotation speed of the rotation speed. When the wafer cassette 101 is completely immersed in the In solvent 104, the descent is stopped. went. Thereafter, the wafer cassette 101 is placed in the In solvent 10.
4 and stopped immediately above the solvent reservoir 103, the rotation speed was increased to 120 rpm, and In remaining partially in the wafer cassette was shaken off to terminate the liquid phase growth.

As a result of cross-sectional observation with a scanning electron microscope and a transmission electron microscope, it was confirmed that the thickness of the grown epitaxial silicon layer was about 15 μm and the crystallinity was good.

Example 2 In this example, a solute was dissolved in a solvent by using a liquid phase growth apparatus having the structure shown in FIG. 3 together with mechanical stirring means (stirring mechanism).
An epitaxial layer of Si was grown. In was used as the solvent, and Si ₂ H ₆ was used as the source gas. With the stirring mechanism 312 kept in a standby room (not shown), the solvent reservoir 303 containing the In solvent 304 is heated by the heater 308 to raise the temperature of the solvent to 960 ° C.
Kept constant. Next, the stirring mechanism 3 which has been waiting in the spare room
12 was introduced into the reaction tube 307 by opening the gate valve 310, and was held immediately above the solvent reservoir 303. The gate valve was kept open thereafter. Source gas inlet pipe 30 with source gas Si ₂ H ₆ together with H ₂ gas (gas flow ratio Si ₂ H ₆ / H ₂ = 1: 1)
6 and jetted into the In solvent 304, and the stirring mechanism 312
Is lowered while rotating at a rotation speed of 20 rpm, and is put into the In solvent 304. When the blade 313 is sufficiently immersed in the In solvent, the lowering is stopped, and the gas is supplied for 30 minutes while stirring and maintaining the position. Continued. After finishing the gas flow,
After pulling up the stirring mechanism 312 to the preliminary chamber,
This time, a wafer cassette 301 on which five 5 "Si wafers 302 are placed is introduced into the reaction tube 307 from the preliminary chamber, and the
03 and held for 10 minutes. By controlling the heater 308, the solvent in the reaction tube 307 is gradually cooled at a rate of -1.5 ° C / min,
When the temperature of the In solvent 304 becomes 950 ° C., the wafer cassette 301 is lowered while rotating at a rotation speed of 10 rpm and is put into the In solvent 304 to completely remove the wafer cassette 3.
01 stops dipping when immersed in In solvent 304,
The liquid phase growth was performed for 45 minutes while rotating while maintaining the position. Thereafter, the wafer cassette 301 is pulled out of the In solvent 304, temporarily stopped just above the solvent reservoir 303, and the rotation speed is increased to 120 rpm, so that the In cassette remaining in the wafer cassette partially remains.
Was shaken off to complete the liquid phase growth. In addition, in FIG.
Reference numeral 5 denotes a reaction product gas, 309 denotes a gas blowing hole, and 311 denotes an exhaust port.

As a result of cross-sectional observation with a scanning electron microscope and a transmission electron microscope, it was confirmed that the thickness of the grown epitaxial silicon layer was about 15 μm and the crystallinity was good.

Example 3 In this example, an epitaxial layer of Si was grown using the apparatus shown in FIG.

Sn was used as a solvent, and SiH ₂ Cl ₂ was used as a source gas.
The apparatus shown in FIG. 2 includes a solvent reservoir 214 made of quartz and a growth tank 20 into which a wafer cassette 201 on which a substrate (wafer) 202 is placed is immersed.
A quartz pipe 209 a, 209 b, 210 returning to the other side of the solvent reservoir 214 through 3 is disposed in the electric furnace 207. Pipes 209a, 209b
Is a heat exchanger. Solvent reservoir 214 and heat exchanger 20
9b is further surrounded by a heater block 208 so that the temperature can be controlled independently. 211 is a circulation rotor, 212 is a gate valve, 206 is a source gas introduction pipe, and 213 is an exhaust port. 204 is a solvent, 20
Reference numeral 5 denotes a reaction product gas.

Sn which has been sufficiently purified in a hydrogen atmosphere is dissolved in a solvent 20
4 and filled in the solvent reservoir 214, the growth tank 203, and the quartz pipes 209a, 209b, and 210.
Keep the internal temperature constant at 950 ° C,
Thus, the temperature of the solvent reservoir 214 was set to be 10 ° C. higher than the temperature in the electric furnace 207 outside the heater block 208, and the solvent 204 was circulated using the rotor 211.

After a sufficient time has passed, 5 "p ⁺ (10
0) Si wafer (wafer doped with a relatively large amount of p-type dopant and having a main surface having a (100) plane orientation) 20
The source gas SiH ₂ Cl ₂ is introduced from the preliminary chamber (not shown) into the growth tank 203 by opening the gate valve 212 and holding the wafer cassette 201 on which five wafers 2 are loaded just above the Sn solvent 204. With H ₂ gas (gas flow ratio SiH ₂ Cl ₂ / H ₂
= 1: 5) in the solvent reservoir 214 through the raw material gas introduction pipe 206
The gas was jetted into the Sn solvent 204, and the gas was kept flowing. When 30 minutes have elapsed, the wafer cassette 201 is lowered while rotating at a rotation speed of 10 rpm, and the Sn in the growth tank 203 is lowered.
Put in the solvent 204 and completely set the wafer cassette 201 to Sn
After dipping in the solvent 204, the descent was stopped, and the liquid phase growth was performed for 60 minutes while rotating while maintaining the position. The wafer cassette 201 is pulled out of the Sn solvent 204,
The liquid phase growth was terminated by temporarily stopping immediately above the solvent 204, increasing the rotation speed to 150 rpm, and shaking off Sn partially remaining in the wafer cassette 201.

As a result of cross-sectional observation with a scanning electron microscope and a transmission electron microscope, it was confirmed that the thickness of the grown epitaxial silicon layer was about 20 μm, and that the crystallinity was good.

Example 4 In this example, an Si layer was grown on a polycrystalline Si substrate using the apparatus shown in FIG. In + Ga (Ga content: 0.1 atm%) was used as a solvent, and SiH ₄ was used as a source gas. Polycrystal formed by casting method
The substrate was processed by processing Si into a width of 40 mm, a length of 250 mm, and a thickness of 0.6 mm, polishing the surface, and then cleaning.

The apparatus shown in FIG.
14 and one side surface of the solvent reservoir 414, comes into contact with a slider 402 on which a plurality of substrates 401 are placed at an opening 403, and returns to the other side surface of the solvent reservoir 414 again. 409 a, 409 b and 410 are arranged in the electric furnace 407. Pipe 409a,
409b is a heat exchanger. The solvent reservoir 414 and the heat exchanger 409b are further surrounded by a heater block 408,
The temperature can be controlled independently. 411 is a circulation rotor, 406 is a source gas introduction pipe, and 413 is an exhaust port. 404 is a solvent and 405 is a reaction product gas.

A solvent reservoir 414 and a flat pipe 409a, using In + Ga sufficiently purified in a hydrogen atmosphere as a solvent 404,
409b and 410 are filled, and the position of the slider 402 is adjusted in advance so that the Si substrate 401 is
At the same time, the temperature inside the electric furnace 407 is kept constant at 950 ° C., and at the same time, the temperature of the solvent reservoir 414 is set at 10 ° C. lower than the temperature inside the electric furnace 407 outside the heater block 408 by the heater block 408. The solvent 404 was circulated using the rotor 411 at a high setting. The length of the opening 403 at this time is 100 mm, and the solvent 4
The circulation speed of No. 04 was 40 mm / min. In this example, 3
One Si substrate was placed on the slider.

Next, the raw material gas SiH ₄ is mixed with the H ₂ gas (gas flow ratio SiH ₄ / H ₂ = 1: 1) through the raw material gas introduction pipe 406 and
The gas was ejected into the + Ga solvent 404, and the gas was kept flowing. After a lapse of 30 minutes, the polycrystalline Si substrate 402 is formed in the opening 403 while the slider 401 is fed at a feed speed of 20 mm / min.
Was brought into contact with an In + Ga solvent 404 to perform liquid phase growth. When all the plurality of polycrystalline Si substrates 402 have passed through the openings 403, the feed of the slider 401 is stopped, and the liquid phase growth is terminated.

As a result of observation of a cross section by a scanning electron microscope and a transmission electron microscope, the thickness of the grown Si layer was about 20 μm. Also, the orientation of the grown Si layer was determined by ECP (Electron
Inspection by the Channeling Pattern method revealed that the crystal orientation of each grain of the underlying polycrystalline Si substrate was inherited. Thus, it was shown that the crystalline Si layer can be continuously grown while feeding the substrate.

In the above-described fourth embodiment, the case where the substrate mounted on the slider is used is shown.
The web-like substrate having the layer adhered thereto is brought into contact with a solvent and rolled.
It is also possible to continuously grow the Si layer while feeding the substrate in one direction by -to-Roll.

Example 5 In this example, an n + / p-type thin film single crystal solar cell was manufactured by using the liquid phase growth method of the present invention. First, a 500 μm-thick p + Si wafer (ρ = 0.01Ω) was used in the same manner as in Example 1 using the apparatus shown in FIG.
· Cm) on which an epitaxial Si layer was grown. The procedure was exactly the same as in Example 1 except that the wafer was changed and that the cooling rate of the In solvent 104 was changed to −2 ° C./min.

When the film thickness of the grown Si layer was evaluated by a step gauge or the like, it was about 30 μm. Next, P is added to the surface of the grown Si layer.
Thermal diffusion of P is performed at 900 ° C. using OCl ₃ as a diffusion source, and n +
A layer was formed, and a junction depth of about 0.5 μm was obtained. Been formed
The dead layer on the surface of the n + layer was wet-oxidized and then removed by etching to obtain a junction depth having an appropriate surface concentration of about 0.2 μm.

Finally, a current collecting electrode (Ti / Pd / Ag (40 nm / 20 nm / 1 μm)) / ITO transparent conductive film (82n
m) was formed on the n + layer, and a back electrode (Al (1 μm)) was formed on the back surface of the substrate, respectively, to obtain a solar cell.

[0040] were measured for the I-V characteristic at AM1.5 (100mW / cm ²⁾ under light irradiation for the thus obtained thin-film single-crystal Si solar cells, the open circuit voltage 0.6V in cell area 6 cm ^2,
The short-circuit photocurrent was 33 mA / cm ² , the fill factor was 0.77, and the energy conversion efficiency was 15.2%.

[0041]

According to the present invention, it has become possible to continuously grow a crystal without interrupting the supply of a raw material in a silicon crystal liquid phase growth method. INDUSTRIAL APPLICABILITY The present invention is suitable as a method for mass production of a device requiring a thickness, particularly a solar cell.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a liquid phase growth apparatus according to the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of an apparatus capable of simultaneously performing dissolution of silicon and liquid phase growth, which is an example of a liquid phase growth apparatus according to the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of an apparatus having mechanical stirring means, which is an example of a liquid phase growth apparatus according to the present invention.

FIG. 4 is a schematic cross-sectional view showing an example of an apparatus in which a substrate and a solvent are in contact at an opening as an example of a liquid phase growth apparatus according to the present invention.

DESCRIPTION OF SYMBOLS 102, 202, 302, 401 Substrates (wafers) 101, 201, 301 Wafer cassettes 103, 214, 303, 414 Solvent reservoir (crucible) 203 Growth tanks 104, 204, 304, 404 Solvent (melt) 105 , 205, 305, 405 Reaction product gas 106, 206, 306, 406 Source gas inlet tube 107, 307 Reaction tube 108, 207, 308, 407 Electric furnace (heater) 208, 408 Heater block 109, 309 Gas outlet 110, 212, 310 Gate valve 111, 213, 311, 413 Exhaust port 209a, 209b, 409a, 409b Heat exchanger (pipe) 210, 410 Pipe 211, 411 Rotor 312 Stirring mechanism 313 Blade 402 Slider 403 Opening

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Noritaka Ukiyo 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (31)

[Claims] A raw material gas containing at least silicon atoms is blown into a solvent to decompose the raw material gas and at the same time dissolve the silicon atoms in the solvent to supply the silicon atoms into the solvent and immerse the substrate in the solvent. Alternatively, a liquid crystal growth method for a silicon crystal, wherein a silicon crystal is grown on the substrate by making contact with the liquid crystal. 2. The method according to claim 1, wherein the solvent and the silicon atoms are stirred by at least one of the source gas, a gas generated by decomposing the source gas, and a gas blown into the solvent together with the source gas. Item 4. A liquid phase growth method for a silicon crystal according to Item 1. 3. The method according to claim 1, wherein the solvent and the silicon are agitated using mechanical means. 4. The method according to claim 1, wherein a solvent comprising a metal is used as the solvent. 5. The method according to claim 1, wherein the metal is In, Sn, Bi, Ga, S.
5. The method for growing a silicon crystal in liquid phase according to claim 4, wherein the method is at least one selected from b. 6. The method according to claim 1, wherein the source gas is made of SiH ₄ . 7. The method according to claim 1, wherein the source gas comprises Si _n H _{2n + 2} (n is an integer of 2 or more). 8. The method according to claim 1, wherein the source gas comprises a halogenated silane. 9. The liquid crystal growth method for a silicon crystal according to claim 1, wherein the source gas contains a dopant. 10. A method for manufacturing a solar cell, comprising at least a step of forming a silicon layer by liquid phase growth,
The raw material gas containing at least silicon atoms is blown into the solvent to supply the silicon atoms into the solvent by dissolving the raw material gas and dissolving the silicon atoms in the solvent at the same time, and immersing or contacting the substrate in the solvent. Forming the silicon layer by growing a silicon crystal on the substrate. 11. The solvent and the silicon atoms are agitated by at least one of the source gas, a gas generated by decomposing the source gas, and a gas blown into the solvent together with the source gas. Item 11. The method for manufacturing a solar cell according to Item 10. 12. The method according to claim 10, wherein the solvent and the silicon are agitated using mechanical means.
2. The method for manufacturing a solar cell according to 1. 13. The method according to claim 10, wherein a solvent made of a metal is used as the solvent. 14. The method according to claim 14, wherein the metal is In, Sn, Bi, Ga,
14. The method for manufacturing a solar cell according to claim 13, wherein the method is at least one selected from Sb. 15. The method for manufacturing a solar cell according to claim 10, wherein the source gas is made of SiH ₄ . 16. The method according to claim 16, wherein said source gas is Si _n H _{2n + 2} (n is 2
The method for manufacturing a solar cell according to any one of claims 10 to 14, wherein: 17. The method for manufacturing a solar cell according to claim 10, wherein the source gas comprises a halogenated silane. 18. The method according to claim 10, wherein the source gas contains a dopant. 19. The method according to claim 10, further comprising a step of forming an n-type layer after the step of forming the silicon layer by liquid phase growth. 20. The method according to claim 19, wherein an n-type layer is formed by diffusing a dopant into a part of the silicon layer. 21. In a silicon crystal liquid phase growth apparatus having means for holding a solvent for dissolving silicon atoms and means for immersing or contacting a substrate in the solvent, a source gas containing at least silicon atoms in the solvent. A liquid crystal growth apparatus for a silicon crystal, comprising: means for injecting liquid. 22. A solvent reservoir for holding a solvent for dissolving silicon atoms, a source gas introduction pipe having an opening in the solvent held in the solvent reservoir, and a wafer cassette for holding a substrate, the solvent cassette comprising: A liquid crystal growth apparatus for a silicon crystal, comprising: a wafer cassette capable of being taken in and out of a solvent held in a reservoir; and a heater. 23. The apparatus for growing a silicon crystal liquid phase according to claim 22, further comprising mechanical stirring means capable of being taken in and out of said solvent. 24. A solvent reservoir and a growth tank for holding a solvent for dissolving silicon atoms, a pipe for circulating the solvent between the solvent reservoir and the growth tank, and a pipe held in the solvent reservoir. A source gas introduction pipe having an opening in a solvent, a wafer cassette holding a substrate, a wafer cassette capable of being taken in and out of a solvent held in the growth tank, and a heater. Liquid crystal growth equipment for silicon crystals. 25. The apparatus for growing a silicon crystal liquid phase according to claim 24, further comprising means for making the temperature of the solvent in the solvent reservoir different from the temperature of the solvent in the growth tank. 26. The silicon crystal according to claim 25, wherein the means for making the temperature of the solvent in the medium reservoir different from the temperature of the solvent in the growth tank comprises a heater block surrounding the solvent reservoir. Liquid phase growth equipment. 27. The liquid phase growth apparatus according to claim 24, wherein at least a part of the pipe is a heat exchanger. 28. A solvent reservoir for holding a solvent for dissolving silicon atoms, a pipe having both ends connected to the solvent reservoir and having openings at other than both ends for circulating the solvent, and A source gas introduction pipe having an opening in the held solvent, a holding member for holding the substrate such that the substrate is in contact with the solvent at the opening, and a heater; and Liquid phase growth equipment. 29. The liquid crystal growth apparatus for a silicon crystal according to claim 28, further comprising means for making the temperature of the solvent in the solvent reservoir different from the temperature of the solvent near the opening. 30. The silicon crystal according to claim 29, wherein the means for making the temperature of the solvent in the solvent reservoir different from the temperature of the solvent near the opening comprises a heater block surrounding the solvent reservoir. Liquid phase growth equipment. 31. The liquid crystal growth apparatus for a silicon crystal according to claim 28, wherein at least a part of the pipe is a heat exchanger.