U.S. patent application number 14/715952 was filed with the patent office on 2015-09-03 for carbon electrode and apparatus for manufacturing polycrystalline silicon rod.
This patent application is currently assigned to Shin-Etsu Chemical Co., Ltd. The applicant listed for this patent is Shin-Etsu Chemical Co., Ltd.. Invention is credited to Masaru Hirahara, Fumitaka Kume, Shinichi Kurotani, Shigeyoshi NETSU, Kyoji Oguro.
Application Number | 20150247239 14/715952 |
Document ID | / |
Family ID | 44066056 |
Filed Date | 2015-09-03 |
United States Patent
Application |
20150247239 |
Kind Code |
A1 |
NETSU; Shigeyoshi ; et
al. |
September 3, 2015 |
CARBON ELECTRODE AND APPARATUS FOR MANUFACTURING POLYCRYSTALLINE
SILICON ROD
Abstract
The upper electrode 31 has a hole 35 extending from an upper
surface 33 to a lower surface 34, a bolt 36 is inserted from the
upper surface 33 of the upper electrode 31 into the hole 35, and
secured in a lower electrode 32 by a screw. A gap 51 between an
inside of the hole 35 and a straight body portion of the bolt 36
allows the upper electrode 31 to slide in all directions in a
placement surface (upper surface of the lower electrode 32 in
contact with the lower surface 34 of the upper electrode 31 in FIG.
2) that is a contact surface with an upper surface of the lower
electrode 32, thereby providing an effect of preventing occurrence
of a crack or a break in a U rod that can be expanded and
contracted in all directions during a vapor phase growth
process.
Inventors: |
NETSU; Shigeyoshi; (Niigata,
JP) ; Kurotani; Shinichi; (Niigata, JP) ;
Oguro; Kyoji; (Niigata, JP) ; Kume; Fumitaka;
(Niigata, JP) ; Hirahara; Masaru; (Niigata,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Shin-Etsu Chemical Co., Ltd. |
Tokyo |
|
JP |
|
|
Assignee: |
Shin-Etsu Chemical Co., Ltd
Tokyo
JP
|
Family ID: |
44066056 |
Appl. No.: |
14/715952 |
Filed: |
May 19, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13508826 |
May 9, 2012 |
|
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|
PCT/JP2010/006270 |
Oct 22, 2010 |
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14715952 |
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Current U.S.
Class: |
118/723R |
Current CPC
Class: |
C01B 33/035 20130101;
C01B 32/225 20170801; C23C 16/458 20130101; C23C 16/24
20130101 |
International
Class: |
C23C 16/458 20060101
C23C016/458; C23C 16/24 20060101 C23C016/24 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 26, 2009 |
JP |
2009-268429 |
Claims
1. A carbon electrode, comprising: a lower electrode secured on a
metal electrode that is an external electrode for electrifying a
silicon core; and an upper electrode located on the lower
electrode, and comprising a securing portion of a core holder that
holds the silicon core on an upper surface side, wherein the upper
electrode is slidable in all directions in a placement surface that
is a contact surface with an upper surface of the lower electrode,
and wherein: (a) the upper electrode is located on the lower
electrode so that a protrusion located in an upper part of the
lower electrode is inserted into a recess located in a lower part
of the upper electrode, an inner size of the recess is larger than
an outer size of the protrusion, and a gap is located between the
recess and the protrusion; or (b) the upper electrode is located on
the lower electrode so that a protrusion located in a lower part of
the upper electrode is inserted into a recess located in an upper
part of the lower electrode, an inner size of the recess is larger
than an outer size of the protrusion, and a gap is located between
the recess and the protrusion.
2-5. (canceled)
6. The carbon electrode according to claim 1, wherein the gap
between the recess and the protrusion is 1 mm or more.
7. The carbon electrode according to claim 1, wherein the upper
electrode and the lower electrode comprise graphite.
8. The carbon electrode according to claim 1, wherein a coefficient
of static friction of the contact surface between the upper
electrode and the lower electrode is 0.3 or less.
9. An apparatus, comprising a pair of metal electrodes, wherein
electric power is supplied from the pair of metal electrodes to
opposite ends of a silicon core assembled into an inverted U-shape
to grow polycrystalline silicon from vapor phase on the silicon
core, wherein both opposite ends of the silicon core assembled into
the inverted U-shape are respectively held by securing portions
provided in carbon electrodes, and at least one of the carbon
electrodes is a carbon electrode according to claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to a carbon electrode used for
manufacturing polycrystalline silicon, and an apparatus for
manufacturing a polycrystalline silicon rod using the carbon
electrode.
BACKGROUND ART
[0002] A Siemens method is known as a method for manufacturing
polycrystalline silicon that is a raw material of monocrystalline
silicon for manufacturing semiconductors or silicon for
manufacturing solar cells. The Siemens method is a method of
bringing a material gas containing chlorosilane into contact with a
heated silicon core to grow polycrystalline silicon from vapor
phase on a surface of the silicon core using a CVD (Chemical Vapor
Deposition) method.
[0003] In growing polycrystalline silicon from vapor phase by the
Siemens method, two vertical silicon cores and one horizontal
silicon core are assembled into an inverted U-shape in a reactor of
a vapor phase growth device, and opposite ends of the vertical
silicon cores are secured to a pair of metal electrodes placed on a
base plate via a pair of core holders.
[0004] Next, a current is applied from the metal electrodes to heat
the silicon cores to a temperature range of 900.degree. C. to
1200.degree. C. in a hydrogen atmosphere, and a material gas, for
example, a mixed gas of trichlorosilane and hydrogen is supplied
from a gas nozzle into the reactor. Then, silicon is grown from
vapor phase on the silicon core, and a polycrystalline silicon rod
having a desired diameter is formed into an inverted U-shape. After
the reactor is cooled, the polycrystalline silicon rod is taken out
of the reactor.
[0005] In recent years, with increasing diameter of a
polycrystalline silicon rod, a crack or a break easily occurs in
the polycrystalline silicon rod during vapor phase growth or
cooling of the polycrystalline silicon rod.
[0006] This may be because, in growing a polycrystalline silicon
rod by a Siemens method, a temperature difference occurs between a
center and a surface in a growing direction (radial direction) of
the silicon rod during or after vapor phase growth, and this causes
stress by thermal expansion or contraction of the polycrystalline
silicon rod.
[0007] If the polycrystalline silicon rod breaks and falls in the
reactor, heavy metal contamination occurs due to contact with an
inner wall of the reactor and metal that constitutes a base plate
or a metal electrode, and also it takes time to collect the
collapsed polycrystalline silicon rod and clean the base plate to
significantly increase an operation cycle time, thereby
significantly reducing productivity.
[0008] Various proposals have been made to prevent occurrence of
such a crack or a break of a polycrystalline silicon rod.
[0009] For example, Japanese Patent Laid-Open No. 8-45847 (Patent
Literature 1) proposes a mounting tool of a carrier member (core)
including at least one spring element provided between a current
lead portion (metal electrode) and an electrode holder (holding
tool of core holder), wherein the spring element allows movement of
the electrode holder with respect to the current lead portion and
also absorbs the movement.
[0010] Japanese Patent Laid-Open No. 2006-16243 (Patent Literature
2) proposes that a seed holding electrode including a carbon seed
holder and a metal electrode, in which the seed holder and the
metal electrode are joined by fitting in a tapered shape, and a
noble metal sheet is joined therebetween in a rubbing manner, is
used to prevent a break of polycrystalline silicon or a carbon
component used in the seed holding electrode due to thermal strain
generated in a cooling step after production of polycrystalline
silicon.
[0011] Japanese Patent Laid-Open No. 2006-240934 (Patent Literature
3) proposes that a carbon holder, in which ends of a silicon core
are electrically connected to electrodes via conductive holders
holding the silicon cores and at least one holder is slidable on an
electrode surface both to left and right in a direction of a line
connecting opposite ends of an inverted U-shaped silicon core, is
used to reduce occurrence of cracks in a polycrystalline silicon
rod.
CITATION LIST
Patent Literature
[0012] Patent Literature 1: Japanese Patent Laid-Open No.
8-45847
[0013] Patent Literature 2: Japanese Patent Laid-Open No.
2006-16243
[0014] Patent Literature 3: Japanese Patent Laid-Open No.
2006-240934
SUMMARY OF INVENTION
Technical Problem
[0015] As described above, during a vapor phase growth process of
polycrystalline silicon by a conventional general Siemens method,
opposite ends of an inverted U-shaped silicon core are secured via
a pair of core holders to a pair of metal electrodes placed on a
base plate. However, if opposite ends of an inverted U-shaped
polycrystalline silicon rod (hereinafter simply referred to as "U
rod" in some cases) are secured to the metal electrodes, expansion
and contraction of the U rod in a horizontal surface direction are
inhibited. The expansion and contraction in the horizontal surface
direction refer to expansion and contraction, for example, in a
direction of a line connecting the opposite ends of the U rod.
[0016] The expansion and contraction of the U rod in the horizontal
surface direction are not limited to those in the direction of the
line connecting the opposite ends of the U rod. For example, if
there is a different U rod near an inside of the U rod, radiant
heat from the different U rod easily expands the inside. Also, if
an outside of the U rod is cooled by a wall of a reactor, the
outside is easily contracted. Thus, the U rod can be expanded and
contracted in all directions in the horizontal surface direction
depending on environments.
[0017] However, the mounting tool disclosed in Patent Literature 1
has a complex structure, and does not allow movement of the
electrode holder other than in the expansion and contraction
directions of the spring element. The seed holding electrode
disclosed in Patent Literature 2 is expensive because a noble metal
sheet is used in a rubbing manner, and the noble metal is easily
incorporated into polycrystalline silicon. Also, the fitting in the
tapered shape may cause the seed holder to slide upward along a
taper in expansion and be released from the electrode. Further, in
the carbon holder disclosed in Patent Literature 3, the
polycrystalline silicon rod is slidable only in the direction of
the line connecting the opposite ends of the silicon core. Thus,
these proposals are insufficient for preventing occurrence of a
crack or a break in a polycrystalline silicon rod.
[0018] The present invention is achieved in view of such problems,
and has an object to provide a technique having a high effect of
preventing occurrence of a crack or a break in a U rod that can be
expanded and contracted in all directions during a vapor phase
growth process of a polycrystalline silicon rod.
Solution to Problem
[0019] To achieve the object, the present invention provides a
carbon electrode used for manufacturing a polycrystalline silicon
rod, including: a lower electrode secured on a metal electrode that
is an external electrode for electrifying a silicon core; and an
upper electrode placed on the lower electrode, and including a
securing portion of a core holder that holds the silicon core on an
upper surface side, wherein the upper electrode is slidable in all
directions in a placement surface that is a contact surface with an
upper surface of the lower electrode.
[0020] In the carbon electrode, the upper electrode includes a hole
extending from an upper surface to a lower surface, a lower end of
a rod-shaped fastening member inserted into the hole is secured to
the lower electrode, a diameter of the hole is larger than a
diameter of a straight body portion of the rod-shaped fastening
member, and a gap is provided between an inside of the hole and the
straight body portion.
[0021] For example, the diameter of the hole is 1 mm or larger than
the diameter of the straight body portion.
[0022] The carbon electrode may have a configuration in which the
upper electrode is placed on the lower electrode so that a
protrusion provided in an upper part of the lower electrode is
inserted into a recess provided in a lower part of the upper
electrode, an inner size of the recess is larger than an outer size
of the protrusion, and a gap is provided between the recess and the
protrusion.
[0023] The carbon electrode may have a configuration in which the
upper electrode is placed on the lower electrode so that a
protrusion provided in the lower part of the upper electrode is
inserted into a recess provided in the upper part of the lower
electrode, an inner size of the recess is larger than an outer size
of the protrusion, and a gap is provided between the recess and the
protrusion.
[0024] For example, the gap between the recess and the protrusion
is 1 mm or more.
[0025] Preferably, the upper electrode and the lower electrode are
made of graphite.
[0026] Preferably, a coefficient of static friction of a contact
surface between the upper electrode and the lower electrode is 0.3
or less.
[0027] The present invention provides an apparatus for
manufacturing a polycrystalline silicon rod in which electric power
is supplied from a pair of metal electrodes to opposite ends of
silicon cores assembled into an inverted U-shape to grow
polycrystalline silicon from vapor phase on the silicon core,
wherein the both opposite ends of the silicon core assembled into
the inverted U-shape are respectively held by securing portions
provided in carbon electrodes, and at least one of the carbon
electrodes is a type of carbon electrode according to the present
invention described above.
Advantageous Effects of Invention
[0028] In the carbon electrode of the present invention, for
example, the upper electrode is secured to the lower electrode by
providing a hole in the upper electrode and inserting the
rod-shaped fastening member into the hole, and the gap is provided
between the hole and the straight body portion of the fastening
member to allow the upper electrode to slide in all directions in a
placement surface that is a contact surface with the upper surface
of the lower electrode.
[0029] This can provide a technique having a high effect of
preventing occurrence of a crack or a break in a U rod that can be
expanded and contracted in all directions during a vapor phase
growth process of a polycrystalline silicon rod.
BRIEF DESCRIPTION OF DRAWINGS
[0030] FIG. 1 is a schematic view showing an exemplary
configuration of an apparatus for manufacturing a polycrystalline
silicon rod of the present invention.
[0031] FIG. 2 is a schematic view showing an exemplary
configuration of a carbon electrode of the present invention.
[0032] FIG. 3 is a schematic view showing another exemplary
configuration of a carbon electrode of the present invention.
[0033] FIG. 4 is a schematic view showing a variant of the carbon
electrode shown in FIG. 3.
DESCRIPTION OF EMBODIMENTS
[0034] Now, an embodiment of the present invention will be
described with reference to the drawings.
[0035] FIG. 1 is a schematic view showing an exemplary
configuration of an apparatus 100 for manufacturing a
polycrystalline silicon rod of the present invention. The
manufacturing apparatus 100 is an apparatus for manufacturing a
polycrystalline silicon rod by growing polycrystalline silicon from
vapor phase on a surface of a silicon core by a Siemens method, and
mainly includes a base plate 1 and a reaction container 10. An
obtained polycrystalline silicon rod includes straight body
portions 6 that grow from vapor phase on vertical portions 5a of a
silicon core 5 assembled into an inverted U-shape, and a bridge
portion 8 that grows from vapor phase on a horizontal portion
(bridge portion 5b).
[0036] On the base plate 1, a metal electrode 2 that supplies a
current to the silicon core 5, a gas nozzle 3 that supplies a
process gas such as a nitrogen gas, a hydrogen gas, or a
trichlorosilane gas, and an exhaust port 4 that exhausts an exhaust
gas are placed.
[0037] The metal electrode 2 is connected to a different metal
electrode (not shown) or a power supply placed outside a reactor,
and receives electric power supplied from outside. An insulator 7
is provided on side surfaces of the metal electrode 2, and the
metal electrode 2 is held between the insulators 7 and extends
through the base plate 1.
[0038] As shown in FIG. 1, to grow polycrystalline silicon from
vapor phase, two vertical cores (5a) and one horizontal core (5b)
are assembled into an inverted U-shape to form the silicon core 5
in the reactor 10, opposite ends of the vertical portions 5a of the
silicon core 5 are secured by core holders 20 held by carbon
electrodes 30, and external electric power supplied to the metal
electrode 2 is applied to the silicon core via the carbon
electrodes 30.
[0039] The metal electrode 2, the base plate 1, and the reactor 10
are cooled with a refrigerant. The core holder 20 and the carbon
electrode 30 are both made of graphite.
[0040] At least one of the carbon electrodes 30 is a carbon
electrode according to the present invention described later, and
is slidable in all directions in a horizontal surface in the
drawing.
[0041] FIG. 2 is a schematic view showing an exemplary
configuration of the carbon electrode 30 of the present invention.
The carbon electrode 30 includes a lower electrode 32 secured on
the metal electrode 2 that is an external electrode for
electrifying the silicon core 5, and an upper electrode 31 placed
on the lower electrode 32. A securing portion of the core holder 20
that holds the silicon core 5a is provided on an upper surface of
the upper electrode 31.
[0042] The upper electrode 31 has a hole (through hole) 35
extending from an upper surface 33 to a lower surface 34, a bolt 36
that is a rod-shaped fastening member is inserted from the upper
surface 33 of the upper electrode 31 through the washer 37 into the
hole 35, and secured in the lower electrode 32 by a screw.
[0043] As shown in FIG. 2, a diameter of the hole 35 is larger than
a diameter of a straight body portion of the bolt 36 so that a gap
51 is created between an inside of the hole 35 and the straight
body portion of the bolt 36. The washer 37 has an outer diameter
about twice larger than the diameter of the hole 35 to prevent the
bolt 36 from entering the hole 35.
[0044] The gap 51 between the inside of the hole 35 and the
straight body portion of the bolt 36 allows the upper electrode 31
to slide in all directions in a placement surface (upper surface of
the lower electrode 32 in contact with the lower surface 34 of the
upper electrode 31 in FIG. 2) that is a contact surface with the
upper surface of the lower electrode 32, thereby providing an
effect of preventing occurrence of a crack or a break in a U rod
that can be expanded and contracted in all directions during a
vapor phase growth process.
[0045] In order to ensure sliding in all directions in the
placement surface, the diameter of the hole 35 is preferably 1 mm
or larger than the diameter of the straight body portion of the
bolt 36. The number of bolts 36 is preferably two or more.
[0046] FIG. 3 is a schematic view of another exemplary
configuration of a carbon electrode 30 of the present invention. In
the carbon electrode 30, the upper electrode 31 is placed on the
lower electrode 32 so that a protrusion provided in an upper part
of the lower electrode 32 is inserted into a recess provided in a
lower part of the upper electrode 31.
[0047] As shown in FIG. 3, an inner size of a recess 38 of the
upper electrode 31 is larger than an outer size of a protrusion 39
of the lower electrode 32, and thus a gap 52 is provided between
the recess 38 and the protrusion 39.
[0048] The gap 52 between the recess 38 and the protrusion 39
allows the upper electrode 31 to slide in all directions in a
placement surface that is a contact surface with an upper surface
of the lower electrode 32, thereby providing an effect of
preventing occurrence of a crack or a break in a U rod that can be
expanded and contracted in all directions during a vapor phase
growth process.
[0049] In order to ensure sliding in all directions in the
placement surface, the gap 52 between the recess 38 and the
protrusion 39 is 1 mm or more.
[0050] FIG. 4 is a schematic view showing a variant of the carbon
electrode 30 shown in FIG. 3. Specifically, in FIG. 3, the upper
electrode 31 is placed on the lower electrode 32 so that the
protrusion provided in the upper part of the lower electrode 32 is
inserted into the recess provided in the lower part of the upper
electrode 31. Meanwhile, an upper electrode 31 is placed on a lower
electrode 32 so that a protrusion 41 provided in a lower part of
the upper electrode 31 is inserted into a recess 42 provided in an
upper part of the lower electrode 32.
[0051] Also in this configuration, as shown in FIG. 4, an inner
size of the recess 42 of the lower electrode 32 is larger than an
outer size of the protrusion 41 of the upper electrode 31, and thus
a gap 53 is provided between the recess 42 and the protrusion 41.
The gap 53 allows the upper electrode 31 to slide in all directions
in a placement surface that is a contact surface with an upper
surface of the lower electrode 32. In order to ensure sliding in
all directions in the placement surface, the gap 53 between the
recess 42 and the protrusion 41 is preferably 1 mm or more.
[0052] In FIGS. 3 and 4, the configuration including one set of the
protrusion and the recess is described, but multiple sets thereof
may be provided. Also in this case, a gap formed between a recess
and a protrusion in each set allows an upper electrode to slide in
all directions within a range of the gap.
[0053] Now, a vapor phase growth process using an apparatus for
manufacturing a polycrystalline silicon rod of the present
invention will be described.
[0054] First, the silicon core 5 is connected to the metal
electrode 2, the reaction container 10 is tightly placed on the
base plate 1, and a nitrogen gas is supplied from the gas nozzle 3
to replace air in the reaction container 10 with nitrogen. At this
time, the air and the nitrogen in the reaction container 10 are
exhausted from the exhaust port 4. After the inside of the reaction
container 10 is replaced with a nitrogen atmosphere, a hydrogen gas
is supplied from the gas nozzle 3 instead of the nitrogen gas to
bring the inside of the reaction container 10 into a hydrogen
atmosphere.
[0055] Then, a heater (not shown) is used to preheat the silicon
core 5 to a temperature of 250.degree. C. or more to be conductive
so that a current efficiently flows through the silicon core 5.
Then, a current is supplied from the metal electrode 2 to the
silicon core 5 to heat the silicon core 5 to 900.degree. C. or
more. Further, a hydrogen gas and also a trichlorosilane gas are
supplied as a material gas to grow polycrystalline silicon from
vapor phase on the silicon core 5 within a temperature range of
900.degree. C. to 1200.degree. C. An unreacted gas and a by-product
gas are exhausted from the exhaust port 4.
[0056] If the temperature is increased to grow polycrystalline
silicon from vapor phase on the silicon core 5, the bridge portion
5b of the silicon core 5 stretches due to expansion, and the vapor
phase growth of polycrystalline silicon advances in that state.
With increasing diameters of the straight body portions 6 and the
bridge portion 8 of the polycrystalline silicon rod, temperature
distribution is formed in a diametrical direction of the
portions.
[0057] For the straight body portions 6 of the polycrystalline
silicon rod, for example, facing surfaces of the pair of straight
body portions 6 that form a U rod radiationally heat each other and
expand, and the core holder 20 and the upper electrode 31 are moved
in a direction to increase space therebetween. An outside of the U
rod is cooled by the reaction container 10 and is lower in
temperature than an inside of the U rod, and the core holder 20 and
the upper electrode 31 are moved in a direction to warp the U rod
outward.
[0058] After the straight body portion 6 and the bridge portion 8
of the polycrystalline silicon rod grow to desired diameters,
supply of a material gas and supply of a current are stopped in
this order, and then the temperature in the reaction container 10
is reduced. At this time, for the U rod with the space increased
during growth, the core holder 20 and the upper electrode 31 are
moved in a direction to reduce space of the bridge portion 8. For
the U rod with a lower temperature on the outside during growth,
the core holder 20 and the upper electrode 31 are moved toward a
center of the reaction container 10.
[0059] In order to smoothly move the upper electrode 31 on the
lower electrode 32, a carbon electrode having low friction of a
surface contact portion between the upper electrode 31 and the
lower electrode 32 needs to be used. From the inventors' diligent
study, it has been found that a carbon electrode having a
coefficient of static friction of 0.3 or less of a surface contact
portion between the upper electrode 31 and the lower electrode 32
allows the upper electrode 31 to smoothly move on the lower
electrode 32.
EXAMPLE 1
[0060] As shown in FIG. 1, a silicon core 5 is assembled into an
inverted U-shape in a reactor 10, and opposite ends of the inverted
U-shaped silicon core 5 are secured to a pair of metal electrodes 2
placed on a base plate 1 via a pair of core holders 20 and a pair
of carbon electrodes 30 made of graphite. One of the carbon
electrodes 30 includes an upper electrode 31 and a lower electrode
32 of types shown in FIG. 2. An inner diameter of a through hole 35
is 10 mm, and a diameter of a bolt 36 is 6 mm.
[0061] Polycrystalline silicons 6 and 8 having diameters of about
120 mm were grown from vapor phase on the silicon core 5 within a
temperature range of 900.degree. C. to 1100.degree. C., and then
the upper electrode 31 was moved 1.5 mm in a direction to increase
space of a polycrystalline silicon rod. Breaks were detected at two
points after the U rod was sheared.
EXAMPLE 2
[0062] Polycrystalline silicon was grown from vapor phase under the
same condition as Example 1 except that one of carbon electrodes 30
includes an upper electrode 31 and a lower electrode 32 of types
shown in FIG. 3. An inner diameter of a recess 38 is 82 mm, and an
outer diameter of a protrusion 39 is 74 mm. After the vapor phase
growth, the upper electrode 31 was moved 3.0 mm in a direction to
reduce space of a polycrystalline silicon rod and warp a U rod
outward. Breaks were detected at two points after the U rod was
sheared.
Comparative Example 1
[0063] Polycrystalline silicon was grown from vapor phase under the
same condition as Example 1 except that carbon electrodes 30
without movement of an electrode were used. Breaks were detected at
five points after the U rod was sheared.
INDUSTRIAL APPLICABILITY
[0064] According to the present invention, a technique can be
provided having a high effect of preventing occurrence of a crack
or a break in a U rod that can be expanded and contracted in all
directions during a vapor phase growth process of a polycrystalline
silicon rod.
REFERENCE SIGNS LIST
[0065] 1 base plate [0066] 2 metal electrode [0067] 3 gas nozzle
[0068] 4 exhaust port [0069] 5 silicon core [0070] 5a vertical
portion [0071] 5b bridge portion [0072] 6 straight body portion of
polycrystalline silicon rod [0073] 8 bridge portion of
polycrystalline silicon rod [0074] 10 reaction container [0075] 20
core holder [0076] 30 carbon electrode [0077] 31 upper electrode
[0078] 32 lower electrode [0079] 33 upper surface of upper
electrode 31 [0080] 34 lower surface of upper electrode 31 [0081]
35 through hole [0082] 36 bolt [0083] 37 washer [0084] 38, 42
recess [0085] 39, 41 protrusion [0086] 51, 52, 53 gap [0087] 100
apparatus for manufacturing polycrystalline silicon rod
* * * * *