JPS61132587A - Apparatus for producing ribbonlike silicon crystal - Google Patents

Abstract

PURPOSE:To produce the titled crystal having low SiC density easily and economically with a simple apparatus, by inclining a capillary die of a ribbonlike silicon crystal pulling apparatus at + or -theta deg. away from the crystal plane by a specific die-inclination mechanism, and pulling up the crystal. CONSTITUTION:The capillary die 31, 32 forming a carbon slit is dipped in a quartz crucible 2 placed in a crystal growth furnace and containing molten silicon liquid 1. Horizontal shafts 61 and 6 are attached to both sides of the top of the die 31, 32 and are inserted freely into the shaft-supporting rings 71 and 72. The slit is made to be inclinable from the bisector of the short side of the slit at + or -theta deg. away from the plane of produced ribbonlike silicon crystal with a die-inclination mechanism 5 in the state of crystal growth. The SiC particle 3a produced in the die 31, 32 is transferred gradually toward the tip of the die 31, 32. The particle 3a at the tip of the left-side die 31 is included in the left surface of the crystal 4 by inclining the die at +theta deg., and the particle of the right-side is included in the right surface by inclining the die at -theta deg.. A crystal having an SiC density of <=1/cm<2> can be produced by this process.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to an apparatus for manufacturing band-shaped silicon crystals.

[Technical background of the invention and its problems] Conventionally, as shown in FIG. 4, a cavity die (hereinafter simply referred to as a die) 3 is used to form a slit in a quartz crucible 2 containing a silicon melt 1. (31, 32) and rising through the slit 1
By bringing a seed crystal (not shown) into contact with the crystal and pulling it up using a pulling drive mechanism under predetermined temperature conditions and pulling speed, a band-shaped silicon crystal 4 is obtained.

Further, the pulled silicon crystal band 4 is cut into a predetermined size using a laser cutting mechanism on the pulling drive mechanism.

By the way, in the conventional device, since the material of the die 3 is carbon, SiC particles are generated in the slit of the die 3 by a chemical reaction between the silicon melt 1 and the carbon of the die 3, and the generated SiC particles are absorbed into the die 3. It passes through the slit and is incorporated into the band-shaped silicon crystal 4 from the tip of the die 3.

The SiC particles of the band-shaped silicon crystal 4 are the band-shaped silicon crystal 4.
When used as a solar cell substrate, it has a very negative effect on the conversion efficiency of the solar cell, and the in-plane SiC density is 1 co//CIR2, the efficiency is about 7%, and the efficiency is 3 co/cI11
2, the efficiency is about 4%.

[Object of the Invention] The present invention has been made in view of the above circumstances, and provides a method for manufacturing band-shaped silicon crystals that can obtain band-shaped silicon crystals with a SiC density of 1 co/α2 or less without the need for large-scale equipment. The purpose is to provide equipment.

[Summary of the Invention] The present invention is capable of tilting a capillary die by ±θ degrees with respect to a band-shaped silicon crystal plane about a line that is on the plane of the die tip and bisects the slit in the direction of its short side. The above objective is achieved by incorporating the SiC particles generated in the silicon crystal band into the band-shaped silicon crystal and reducing the SiC particles at the tip of the die.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a main part of an embodiment of the present invention, in which a quartz crucible 2 containing a silicon melt 1 is installed in a growth furnace (not shown), and a quartz crucible 2 containing a silicon melt 1 is installed in a growth furnace (not shown). Capillary die 3 (31,
32) will be erected. Rotating shafts 6 (6r, 62) are provided at both ends of the tip of the die 3, with the axial direction being horizontal, and each of the rotating shafts 6 (61, 62)
The crucible 1 is loosely inserted and attached to the annular rotating shaft attachment members 7 (71, 72) provided correspondingly to the upper ends of the crucible 1, respectively. The die slope 1 structure 5 composed of the rotating shaft 6 (61, 62) and the rotating shaft mounting member 7 (71, 72) has the die 3 on the die tip plane and the slit in the direction of its short side. The band-shaped silicon crystal 4 is centered on the line that bisects the
It can be tilted in a crystal growth state by ±θ degrees with respect to the plane.

That is, a seed crystal is brought into contact with the silicon melt 1 rising through the slit of the die 3, and the seed crystal is pulled up by a pulling drive mechanism at a predetermined temperature condition and pulling speed, thereby obtaining a band-shaped silicon crystal 4. .

FIG. 2 is a cross-sectional view of the die 31 and 32 in the thickness direction.
The SiC particles 3a generated inside the die 3
1.32 and is taken into the band-shaped silicon crystal 4.

3(a) and (C) show the side surface of the die 4 being ±θ with respect to the surface of the band-shaped silicon crystal 4, centered on a line that is on the plane of the die tip and bisects the slit in the direction of its short side. It shows the incorporation of SiC particles 3a into band-shaped silicon crystal 4 when tilted. Figure 3(b) is similar to Figures 3(a) and (C).
This shows the state of crystal growth with a tilt of 0 degrees after the die 4 is tilted as shown in FIG. The fact that the SiC particle density of the band-shaped silicon crystal obtained in this example can be well controlled will be explained in detail. In the initial state, as shown in FIG. 2, the SiC particles 3a generated inside the die 3 gradually move to the tip of the die 3 as the silicon melt 1 moves, and from the tip of the die 3 a band-shaped silicon crystal is formed. It is taken in by 4. Under this condition, the SiC particles 3a accumulate at the tip of the die 3, and when they reach a certain size, they are incorporated into the band-shaped silicon crystal 4.

Next, as shown in FIG. 3(a), the dies 31 and 32 are
When tilted at 6 degrees, the S accumulated at the tip of die 31 on the left side
The iC particles 3a are incorporated into the left side surface of the band-shaped silicon crystal 4. As roughly shown in Figure 3(C), die 31.32
When tilted by +6 degrees, the SiC particles 3a accumulated at the tip of the die 32 on the right side are taken into the right side surface of the band-shaped silicon crystal 4. FIG. 3<1)) shows dies 31 and 32 where the dies 3t and 32 have been tilted by ±θ degrees and the inclination is 0 degrees, and no SiC particles 3a are present at the tips of the dies 3r and 32. Therefore, it is shown that there are no SiC particles in the band-shaped silicon crystal 4 as well. In reality, by tilting the die 3 at an interval of 10cI11 by θ=27 degrees with the length of the band-shaped silicon crystal 4, the SiC particles 3a at the tip of the die 3 are instantly incorporated into the band-shaped silicon crystal 4, and the subsequent growth Si
It was possible to obtain a band-shaped silicon 4 having a C density of approximately O pieces/α2.

The portion of the band-shaped silicon crystal that incorporates the accumulated SiC particles may be removed when cutting the band-shaped silicon crystal into a size of 95 mm x 95 mm. Band-shaped silicon crystals obtained in this way (SiC density 0 pieces/α2
), we were able to obtain a solar cell light conversion efficiency of 9%. Furthermore, in the prior art, the band-shaped silicon crystal is cut into the required size using a laser at the upper part of the pulling drive mechanism.

On the other hand, in the present invention, the thickness of the band-shaped silicon crystal is partially thinned due to the 18-degree inclination of the die, so by applying force to the band-shaped silicon crystal at the top of the pulling drive mechanism, the band-shaped silicon crystal is Separation can be performed at thinner areas. Therefore, it is possible to suppress cracks and minute defects that are present in the band-shaped silicon crystal during laser cutting.

Roughly using the present invention, an increase in pulling speed of about 15% was obtained.

Note that the tilting angle θ varies depending on the spacing between the die tips; for example, when the spacing is 500 μm, θ is 12° to 44°.
4″ to 15° in the case of 800 μm.

[Effects of the Invention] As described above, according to the present invention, it is possible to lower the SiC density within the band-shaped silicon crystal plane, increase the pulling speed, and eliminate the cutting mechanism. Further, the present invention overcomes the drawbacks of the prior art, and has the major characteristics that the structure is simple, the device is inexpensive, and no special control mechanism is required.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG.
Figure 3(a) is a diagram showing how C particles are incorporated into a band-shaped silicon crystal. Figure 3(C) is a diagram showing how SiC particles are incorporated into the right side of the band-shaped silicon crystal when the die is tilted by +6 degrees, and Figure 3(b) is a diagram showing how SiC particles are incorporated into the right side of the band-shaped silicon crystal when the die is tilted by +6 degrees.
A diagram showing the growth state of band-shaped silicon crystals after the operation of C),
FIG. 4 is a perspective view showing a conventional manufacturing apparatus for band-shaped silicon crystals. DESCRIPTION OF SYMBOLS 1... Silicon melt, 2... Quartz crucible, 31° 32... Capillary die, 4... Band-shaped silicon crystal, 3a... SiC particles, 5... Die tilting mechanism, 6
1°62... Rotating shaft, 71.72... Rotating shaft mounting member. 2 Figure 2

Claims (1)

[Claims] A capillary die having a slit is provided in a crucible containing a silicon melt, a seed crystal is brought into contact with the silicon melt rising through the slit, and the seed crystal is pulled up to pull up a band-shaped silicon crystal. In an apparatus for producing a band-shaped silicon crystal, the capillary die is placed on the die tip plane and is in a crystal growth state of ±θ degrees with respect to the band-shaped silicon crystal surface centered on a line that bisects the slit in the direction of its short side. A device for producing a band-shaped silicon crystal, characterized in that it is provided with a die tilting mechanism that can tilt the die.