CN102797037B

CN102797037B - Polycrystal silicon ingot and manufacture method, solar cell

Info

Publication number: CN102797037B
Application number: CN201210017969.0A
Authority: CN
Inventors: 郑志东; 汤旋; 彭春球; 石郧熙; 翟蕊; 李娟�; 刘文涛
Original assignee: Zhejiang Yuhui Yangguang Energy Resources Co Ltd
Current assignee: RENESOLA ZHEJIANG Ltd
Priority date: 2011-05-26
Filing date: 2012-01-19
Publication date: 2015-08-12
Anticipated expiration: 2032-01-19
Also published as: CN102797037A

Abstract

The invention discloses a kind of manufacture method of polycrystal silicon ingot, comprising: the container bottom in polycrystal silicon ingot growth furnace lays seed crystal, form inculating crystal layer; Solid-state silicon raw material is loaded into the top of inculating crystal layer; Described container is heated, melts described silicon raw material and the described inculating crystal layer of part, form liquid level, at least keep the part inculating crystal layer contacted with container bottom to be solid-state; Control the thermal field in polycrystal silicon ingot growth furnace, crystallization is carried out to liquid level and forms crystallizing layer, moved the growth of polycrystal silicon ingot to make solid-liquid interface to the direction away from described container bottom.The polycrystal silicon ingot foreign matter content adopting method of the present invention to produce is low, and the solar cell cost produced is low, reduction coefficient is low, and photoelectric transformation efficiency is high.

Description

Polycrystal silicon ingot and manufacture method, solar cell

Technical field

The present invention relates to silicon single crystal, the manufacturing technology of polysilicon and photoelectric field, particularly relate to a kind of polycrystal silicon ingot and manufacture method, solar cell.

Background technology

Transform light energy can be electric energy by solar cell, and the height of photoelectric transformation efficiency and the speed of cell decay are the important parameters weighing solar cell quality.At present, according to the difference of material, solar cell is mainly divided into monocrystaline silicon solar cell and polysilicon solar cell two kinds.

Wherein, silicon single crystal ingot is by after the silicon raw materials melt containing doping agent, silicon metal is pulled out melt region and crystallization formed, the method of usual produce single crystal silicon ingot has melt vertical pulling method (Czochralski, be called for short CZ method) and floating zone melting (being called for short FZ method), CZ method is slowly pulled out from the silicon liquid of melting by silicon single crystal ingot, and FZ method supplies solid materials by melt region and again solidifies on the opposite side of described melt region.

Because intercrystalline orientation is fixing, therefore the photoelectric transformation efficiency of monocrystaline silicon solar cell is higher, but, from production cost, the silicon single crystal single output adopting these two kinds of methods to produce is few, and production cost is higher, and the size of the silicon single crystal rod of especially FZ method production is less; The performance of the silicon single crystal rod produced, radially-arranged defect struchures is comprised in silicon single crystal rod, as ring and the space of oxygen induction stacking fault (OSF), or " whirlpool " defect of vacancy cluster, for CZ method, due to the use of quartz crucible, inevitably more oxygen impurities will be comprised in silicon single crystal ingot inside, after oxygen impurities is combined with the boron of doping, boron oxygen (B-O) complex body that produces is again cause the principal element that solar cell decays, therefore, the reduction coefficient of the solar cell using this silicon single crystal rod to make is higher.

Polycrystal silicon ingot normally adopts the method for casting to process, and casting polycrystalline silicon is that the raw silicon of melting is placed in quartz crucible, and by controlling the process of cooling of molten silicon, obtains after making molten silicon crystallization.Relative to silicon single crystal ingot, more defect is there is in polycrystal silicon ingot, crystal grain is little, crystal boundary between conventional polycrystalline silicon crystal grain and dislocation more, thus cause the quick compound of electric charge carrier, cause minority carrier life time low, and, because the orientation between crystal grain is random, cause being difficult to carry out good texture to wafer surface, make conventional polycrystalline silicon solar cell lower than the photoelectric transformation efficiency of monocrystaline silicon solar cell, but the oxygen level in polycrystal silicon ingot can control in good level, thus make the reduction coefficient of polysilicon solar cell lower.

Summary of the invention

For solving the problems of the technologies described above, the invention provides a kind of polycrystal silicon ingot and manufacture method, solar cell, relative to monocrystaline silicon solar cell of the prior art, at the bottom of the cost of the solar cell adopting the polycrystal silicon ingot that provides of the embodiment of the present invention to produce, reduction coefficient is lower, simultaneously, relative to polysilicon solar cell of the prior art, the photoelectric transformation efficiency of the solar cell that the polycrystal silicon ingot adopting the embodiment of the present invention to provide is produced is higher.

For solving the problem, embodiments provide following technical scheme:

A manufacture method for polycrystal silicon ingot, comprising:

Container bottom in polycrystal silicon ingot growth furnace lays seed crystal, forms inculating crystal layer;

Solid-state silicon raw material is loaded into the top of described inculating crystal layer;

Described container is heated, melt described silicon raw material and the described inculating crystal layer of part, to form liquid level, solid-liquid interface is obtained between unfused inculating crystal layer and described liquid level, wherein, the position of described solid-liquid interface is monitored in this heat-processed, the part inculating crystal layer contacted with described container bottom is at least kept to be solid-state, this heat-processed is specially: heat described container, keep container top temperature higher than the fusing point of silicon, container bottom temperature is lower than the fusing point of silicon, form the thermograde perpendicular to container bottom, silicon raw material in described container and part seed crystal are melted from top to bottom successively, and retaining part inculating crystal layer is solid-state,

Control the thermal field in described polycrystal silicon ingot growth furnace, crystallization is carried out to described liquid level and forms crystallizing layer, move to the direction away from described container bottom to make solid-liquid interface, complete the growth of polycrystal silicon ingot, this process is specially: the power adjusting the heating installation of described container top and/or bottom, changes thermal field in stove, forms the thermograde perpendicular to container bottom, carry out crystallization to described liquid level, the temperature in described container is along going up gradually perpendicular to container bottom direction upwards.

Preferably, the thermal field in the described polycrystal silicon ingot growth furnace of described control, carry out crystallization to described liquid level and form crystallizing layer, to make solid-liquid interface move to the direction away from described container bottom, the process completing the growth of polycrystal silicon ingot is specially:

Control the thermal field in described polycrystal silicon ingot growth furnace, crystallization is carried out to described liquid level and forms crystallizing layer, move to the direction away from described container bottom to make solid-liquid interface;

After described solid-liquid interface moves respective distance to the direction away from described container bottom, enter melt back crystallisation process, after at least performing once described melt back crystallisation process, obtain polycrystal silicon ingot;

Wherein, described melt back crystallisation process comprises, control the thermal field in described polycrystal silicon ingot growth furnace, melt back is carried out to described crystallizing layer, described solid-liquid interface is moved to the direction near described container bottom, afterwards, control the thermal field in described polycrystal silicon ingot growth furnace, crystallization is carried out to liquid level, to make described solid-liquid interface move to the direction away from described container bottom, described solid-liquid interface is less than the distance of described solid-liquid interface to the direction movement away from described container bottom to the distance of the direction movement near described container bottom.

Preferably, describedly carry out in heat-processed to described container, keep described solid-liquid interface substantially parallel with the bottom of described container.

Preferably, in the process of described fusing described silicon raw material and the described inculating crystal layer of part, control the temperature of the base bottom below described container bottom between 1320 DEG C-1420 DEG C, the temperature controlling described upper vessel portion between 1450 DEG C-1600 DEG C, to form vertical thermograde in the above-described container.

Preferably, control the thermal field in described polycrystal silicon ingot growth furnace, carry out also comprising before crystallization forms crystallizing layer to described liquid level:

In the process melting described silicon raw material and the described inculating crystal layer of part, monitor the position of described solid-liquid interface, the height of solid-liquid interface is measured;

When the height measuring the solid-liquid interface obtained is less than the thickness of described inculating crystal layer, start to carry out crystallization to described liquid level.

Preferably, described is adopt the height of solid-liquid interface monitoring device to solid-liquid interface to measure to the mode that the height of solid-liquid interface is measured.

Preferably, when starting to carry out crystallization to described liquid level, the height of described solid-liquid interface is the 1%-80% of described inculating crystal layer thickness.

Preferably, the paving mode of described inculating crystal layer is: laid by the bulky single crystal seed crystal that a monoblock is substantially identical with container bottom size and shape and form, or be spliced by multiple fritter single crystal seed, or formed by the block slab laying under cutting from described polycrystal silicon ingot main body, described polycrystal silicon ingot contains the large-sized monocrystalline silicon region of continuous print, and the crystalline orientation of described monocrystalline silicon region is identical with the crystalline orientation of the described seed crystal be positioned at below it.

Preferably, described inculating crystal layer is be spliced by the block slabs of the multiple fritters under cutting from described polycrystal silicon ingot main body.

Preferably, described inculating crystal layer is laid by the block slab of the entirety under cutting from described polycrystal silicon ingot main body to form.

Preferably, the poly-region place on described block slab is cut with groove.

Preferably, the profile of described groove is V-arrangement or trapezoidal.

Preferably, described block slab be bottom for having the polyhedron of regular shape, top is the structure of boss.

Preferably, described seed crystal be bottom for having the polyhedron of regular shape, top is the structure of boss.

Preferably, described inculating crystal layer comprises the monocrystalline silicon layer of at least one crystalline orientation.

Preferably, the process forming described inculating crystal layer is specially, and the seed crystal splicing tiling adopting crystalline orientation identical forms described inculating crystal layer, and described inculating crystal layer is substantially parallel with described container bottom.

Preferably, the process forming described inculating crystal layer is specially:

Adopt the seed crystal splicing paving with first crystal orientation, cover the subregion of described container bottom, form the seeded region with first crystal orientation;

The seed crystal with the second crystalline orientation is adopted to cover the subregion of described container bottom, form the seeded region with the second crystalline orientation, described there is first crystal orientation seeded region and the described seeded region with the second crystalline orientation jointly form described inculating crystal layer, described inculating crystal layer is substantially parallel with described container bottom, wherein, the seeded region described in first crystal orientation is surrounded by the described seeded region with the second crystalline orientation.

Preferably, the process solid-state silicon raw material being loaded into the top of described inculating crystal layer is specially:

Short grained silicon raw material is loaded into the top of described inculating crystal layer, to fill the gap between described seed crystal and the gap between described inculating crystal layer and described container side wall;

The silicon raw material of large volume is loaded into the top of described small-particle silicon raw material.

Preferably, the thickness of described inculating crystal layer is 10mm-100mm.

Preferably, when first time starts crystallization, the thickness of solid seed crystal layer is 1mm-50mm.

Preferably, when first time starts crystallization, the thickness of solid seed crystal layer is 3mm-30mm.

Preferably, the area of described inculating crystal layer occupies the 50%-99% of described container bottom area.

Preferably, described container is quartz crucible, silicon carbide crucible or silicon nitride crucible, and described pedestal is graphite base.

The embodiment of the invention also discloses a kind of solar cell, adopt the polycrystal silicon ingot that above-described method is produced, this solar cell comprises:

Wafer, described wafer has continuous large-sized monocrystalline silicon region that crystalline orientation is consistent;

P-N junction in described wafer;

Conductive contact on described wafer.

The embodiment of the present invention is also public a kind of solid-liquid interface monitoring device, for monitoring the interface location of solid multi-crystalline silicon and liquid polysilicon in polycrystalline silicon ingot or purifying furnace, comprising:

The guide pipe (6) communicated with the furnace chamber of described polycrystalline silicon ingot or purifying furnace;

Be arranged on the winding box (1) on described guide pipe (6) top;

To be arranged in described winding box (1) inner chamber and to be wound with the roll (2) of wireline (5);

Be positioned at described guide pipe (6), be connected with described wireline (5) and the gauge stick (9) in described furnace chamber can be deep into along with the unwrapping wire of described wireline (5);

Be arranged on described winding box (1) outside and be connected with described roll (2) to control that described roll (2) rotates shakes and take turns (4);

Be arranged on described winding box (1) outside and with described roll (2) the circumference ratchet (3) of locating and the ratchet (13) that coordinates with described ratchet (3);

Be arranged on described guide pipe (6) outside to measure the measuring scale (10) of described gauge stick (9) miles of relative movement.

Preferably, also comprise and connect described wireline (5) and the orienting lug (8) of gauge stick (9), the sidewall of this orienting lug (8) and the contact internal walls of described guide pipe (6) and both relatively sliding can occur.

Preferably, the bottom of described guide pipe (6) is provided with the water jacket (12) that can communicate with the furnace chamber of described polycrystalline silicon ingot or purifying furnace.

Preferably, the stay-bolt (11) being evenly centered around outside described guide pipe (6) and two ends and being connected with the tongued and grooved flanges (7) at described guide pipe (6) two ends respectively is also comprised.

Preferably, described measuring scale (10) is arranged on described stay-bolt (11).

Preferably, described guide pipe (6) is silica tube.

The embodiment of the invention also discloses a kind of solid-liquid interface monitoring device, for monitoring the interface location of solid multi-crystalline silicon and liquid polysilicon in polycrystalline silicon ingot or purifying furnace, comprising:

The guide pipe (06) communicated with the furnace chamber of described polycrystalline silicon ingot or purifying furnace;

Be arranged on the winding box (01) on described guide pipe (06) top;

To be arranged in described winding box (01) inner chamber and to be wound with the roll (02) of wireline (05);

Be positioned at described guide pipe (06), be connected with described wireline (05) and the gauge stick (09) in described furnace chamber can be deep into along with the unwrapping wire of described wireline (05);

Be arranged on described winding box (01) outside, drive the rotation motor (03) that described roll (02) rotates;

To be arranged in described winding box (01) and to be passed by described wireline (05), and to control the vernier switch (010) that described rotation motor (03) stops when touching solid multi-crystalline silicon in the bottom of gauge stick (09);

Be arranged on described winding box (01) outside to measure described gauge stick (09) miles of relative movement and observed value to be converted into the encoder (04) of electrical signal;

Receive electrical signal that described encoder (04) sends and be shown as the indicating meter of observed value;

Control the controller that described rotation motor (03) is opened or stopped.

Preferably, also comprise and connect described wireline (05) and the orienting lug (08) of gauge stick (09), the sidewall of this orienting lug (08) and the contact internal walls of described guide pipe (06) and both relatively sliding can occur.

Preferably, the bottom of described guide pipe (06) is provided with the water jacket (012) that can communicate with the furnace chamber of described polycrystalline silicon ingot or purifying furnace.

Preferably, the stay-bolt (011) being evenly centered around outside described guide pipe (06) and two ends and being connected with the tongued and grooved flanges (07) at described guide pipe (06) two ends respectively is also comprised.

Preferably, also comprise and be arranged on described stay-bolt (011), signal can be sent to described controller, control top limit switch (013) and bottom limit switch (014) that described rotation motor (03) quits work to prevent the excessive rising of described orienting lug (08) and decline.

Preferably, the gas interface (015) being arranged on described winding box (01) and argon gas can be filled with to the inner chamber of described winding box (01) and guide pipe (06) is also comprised.

Preferably, described guide pipe (06) is silica tube.

Compared with prior art, technique scheme has the following advantages:

The technical scheme that the embodiment of the present invention provides, the method of casting is adopted to produce polycrystal silicon ingot, inculating crystal layer is formed by laying big area seed crystal in advance at container bottom, the growth of monocrystalline silicon region is guided by seed crystal, and by repeatedly melt back crystallization, make to comprise continuous large-sized monocrystalline silicon region in the polycrystal silicon ingot produced, the polycrystal silicon ingot namely cast out is by the major part monocrystalline silicon region consistent with seed crystal orientation, and the polysilicon region composition of small part.Because the inculating crystal layer of bottom in castingprocesses has completely cut off the oxygen of container bottom, thus reduce the oxygen impurities content in polycrystal silicon ingot, and, containing large-sized monocrystalline silicon region in polycrystal silicon ingot.Therefore, the solar cell that the polycrystal silicon ingot adopting the embodiment of the present invention to provide is produced, monocrystaline silicon solar cell reduction coefficient more of the prior art is lower, and polysilicon solar cell photoelectric transformation efficiency more of the prior art is higher.

And, polycrystal silicon ingot is formed owing to adopting the mode of repeatedly melt back crystallization in the present embodiment, slow down the setting rate of crystal to a certain extent, make impurity (as silicon carbide, silicon nitride etc.) there is time enough to carry out fractional condensation, even if the impurity in raw material dissolves in the solution after can separating out again, thus avoid impurity and be deposited in the crystalline region solidified, and then the Hard Inclusion decreased in cast main body and impurity enriched layer, defect concentration in the polycrystal silicon ingot produced is reduced greatly, also improve minority carrier life time to a certain extent, thus improve the photoelectric transformation efficiency of solar cell.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings

The schematic flow sheet of Fig. 1 manufacture method of polycrystal silicon ingot disclosed in the embodiment of the present invention one;

The schematic flow sheet of Fig. 2 manufacture method of polycrystal silicon ingot disclosed in the embodiment of the present invention two;

Melt back process of growth schematic diagram in Fig. 3 a-Fig. 3 d polycrystal silicon ingot making processes disclosed in the embodiment of the present invention two;

The schematic flow sheet of Fig. 4 manufacture method of polycrystal silicon ingot disclosed in the embodiment of the present invention three;

Fig. 5 is seed crystal paving mode vertical view disclosed in the embodiment of the present invention three;

Fig. 6 is the disclosed sectional view loading silicon raw material mode of the embodiment of the present invention three;

Fig. 7 is the sectional view of the polycrystal silicon ingot produced in the embodiment of the present invention three;

The schematic flow sheet of Fig. 8 manufacture method of polycrystal silicon ingot disclosed in the embodiment of the present invention four;

Fig. 9 is seed crystal paving mode vertical view disclosed in the embodiment of the present invention four;

Figure 10 is the sectional view of the polycrystal silicon ingot produced in the embodiment of the present invention four;

Figure 11 is seed crystal paving mode vertical view disclosed in the embodiment of the present invention six;

Figure 12 is the profile front view of the inculating crystal layer disclosed in the embodiment of the present invention seven;

Figure 13 is the profile front view of the inculating crystal layer disclosed in the embodiment of the present invention eight;

Figure 14 is the profile front view of the inculating crystal layer disclosed in the embodiment of the present invention nine;

The schematic flow sheet of Figure 15 manufacture method of polycrystal silicon ingot disclosed in the embodiment of the present invention ten;

The structural representation of Figure 16 manual measurement device disclosed in the embodiment of the present invention 12;

The cooperation schematic diagram of ratchet and pawl in Figure 17 manual measurement device disclosed in the embodiment of the present invention 12;

The structural representation of Figure 18 self-operated measuring unit disclosed in the embodiment of the present invention 13.

In Figure 16-Figure 18:

Winding box 1, roll 2, ratchet 3, shake wheel 4, wireline 5, guide pipe 6, tongued and grooved flanges 7, orienting lug 8, gauge stick 9, measuring scale 10, support bar 11, water jacket 12, ratchet 13, winding box 01, roll 02, rotation motor 03, encoder 04, wireline 05, guide pipe 06, tongued and grooved flanges 07, orienting lug 08, gauge stick 09, vernier switch 010, support bar 011, water jacket 012, top limit switch 013, bottom limit switch 014, gas interface 015.

Embodiment

Just as described in the background section, the silicon single crystal ingot production capacity adopting the mode of prior art to produce is little, and production cost is high, and due to oxygen impurities more, make the reduction coefficient of the solar cell adopting silicon single crystal ingot of the prior art to make higher; And adopt the polycrystal silicon ingot produced in prior art, although production capacity is large, but because polysilicon self grain orientation is random, chemical process can not be adopted to carry out good texture to its surface, thus can better not reduce polysilicon surface to light reflectance, raising, to features such as the specific absorptioies of light, causes polysilicon solar cell photoelectric transformation efficiency low.

The defect of silicon single crystal is formed due to the mode of production itself, and the random defect of polysilicon grain orientation is by itself structures shape, and produce same product in the same way if still adopt, these defects are exactly inevitable.

In addition, polycrystal silicon ingot is except the defect of the self structure such as grain orientation is random, also has other defect caused because of technological reason, as the defect such as dislocation and pit of impurity Hard Inclusion and initiation thereof, contriver studies discovery, occur that the reason of these situations is, in the directional freeze process of crystal growth, because segregation coefficient is less, carbon in silicon raw material, the impurity such as nitrogen can in the enrichment of solid-liquid interface place, when the speed of growth is than time very fast, impurity has little time fractional condensation, silicon carbide will be formed, silicon nitride etc., separate out from solution, retain in solid multi-crystalline silicon after crystallisation, become impurity enriched layer or the Hard Inclusion of pinning in crystal.

If impurity is concentrated in samdwich in cast main body, then the part silico briquette comprising impurity layer will be cut, and whole silico briquette even can be caused in some cases to scrap; If impurity is separated out with the form of Hard Inclusion, then can become the initiating accident sequence of the defect such as dislocation and pit, cause defect concentrations in crystals to increase, Quality Down, and, because the hardness of silicon carbide, silicon nitride is all higher than silicon crystal, in section and evolution process, its higher hardness can affect the quality of cutting greatly, stria, groove is formed at cutting surfaces, even break, whole silico briquette is scrapped, can not the finished product be processed as.

Based on above reason, contriver considers that the output of the polycrystal silicon ingot that castmethod is produced is larger, and the oxygen level of the polycrystal silicon ingot produced is lower, exactly solve the defect of the mode of production of silicon single crystal ingot, and, monocrystaline silicon solar cell is due to the reason of material, exactly there is no many defects of polysilicon solar cell, if the advantage of the two is combined, the mode of producing polycrystal silicon ingot is adopted to go to produce the polycrystal silicon ingot containing large-sized monocrystalline silicon region, the shortcoming of monocrystaline silicon solar cell and polysilicon solar cell in prior art should be able to be solved to a certain extent.

Further, adopt the method for casting to carry out, in production process, the mode of the setting rate slowing down crystal can being taked, reduce the Hard Inclusion in cast main body and impurity enriched layer, thus improve the quality of finished product.

It is more than the core concept of the application, below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

Set forth a lot of detail in the following description so that fully understand the present invention, but the present invention can also adopt other to be different from alternate manner described here to implement, those skilled in the art can when without prejudice to doing similar popularization when intension of the present invention, therefore the present invention is by the restriction of following public specific embodiment.

Secondly, the present invention is described in detail in conjunction with schematic diagram, when describing the embodiment of the present invention in detail; for ease of explanation; represent that the sectional view of device architecture can be disobeyed general ratio and be made partial enlargement, and described schematic diagram is example, it should not limit the scope of protection of the invention at this.In addition, the three-dimensional space of length, width and the degree of depth should be comprised in actual fabrication.

Embodiment one

On basis based on above-mentioned research, embodiments provide a kind of manufacture method of polycrystal silicon ingot, the schema of the method as shown in Figure 1, comprises the following steps:

Step S101: the container bottom in polycrystal silicon ingot growth furnace lays seed crystal, forms inculating crystal layer;

Wherein, described inculating crystal layer can be the bulky single crystal seed crystal that a monoblock is substantially identical with container bottom size and shape, also can be spliced by multiple fritter single crystal seed.And, described seed crystal is the silicon single crystal that crystalline orientation is fixed, described inculating crystal layer comprises the monocrystalline silicon layer of at least one crystalline orientation, and preferably, the seed crystal in the present embodiment is the silicon single crystal of (100), (110) or (111) orientation.

Concrete, in the present embodiment, inculating crystal layer comprises the monocrystalline silicon layer of at least one crystalline orientation, in other words, described inculating crystal layer all can select to have same crystalline orientation silicon single crystal, as all adopted the silicon single crystal with (100) orientation, also the silicon single crystal with first crystal orientation can partly be selected, another part selects the silicon single crystal with the second crystalline orientation, described first crystal orientation is different from described second crystalline orientation, as: a part selects the silicon single crystal with (100) orientation, another part selects the silicon single crystal with (110) orientation, which kind of seed crystal of concrete selection, determine according to the requirement to polycrystal silicon ingot.

The present embodiment this do not limit the shape and size of described seed crystal, described inculating crystal layer can be the bulk seed crystal substantially identical with container bottom size and shape, also can be pieced together by multiple fritter seed crystal and be formed, if the latter, in order to process of deployment convenience and meet the needs of complete tiling, the well-regulated geometrical shape of the best tool of cross-sectional shape of seed body, preferred described seed crystal shape is rectangle, be more preferably square, larger seed crystal to be selected as far as possible, to make the gap pieced together between the seed crystal of formation little as far as possible, to ensure the quality of polycrystal silicon ingot.Shape, size, paving mode etc. about described seed crystal describe in detail in the examples below, are not specifically limited in the present embodiment.

And, also the paving mode of described inculating crystal layer is not specifically limited in the present embodiment, but in order to ensure the quality of the silicon single crystal in polycrystal silicon ingot, preferably, described seed crystal is layed in the region intermediate of described container, in addition, in order to better control making processes and the quality of described polycrystal silicon ingot, described inculating crystal layer should keep substantially parallel or less parallel with described container bottom.

Same, also the thickness of described inculating crystal layer is not specifically limited in the present embodiment, determine with concrete production process and working condition, preferably, the thickness of described inculating crystal layer is 2mm-400mm, preferred, and the thickness of described inculating crystal layer is 10mm-100mm, preferred, the thickness of described inculating crystal layer is 10mm-60mm.

In addition, container shapes in polycrystal silicon ingot growth furnace in the present embodiment and material are determined by the polycrystal silicon ingot growth furnace adopted in production process, generally, due in the present embodiment be adopt casting mode produce polycrystal silicon ingot, described container is crucible, and more general is quartz crucible, certainly, what described container can also select other to can be used for the castingprocesses of polycrystal silicon ingot can disposable crucible or reusable crucible, as silicon carbide crucible or silicon nitride crucible etc.

" casting " described in the present embodiment process specifically refers to and is forming silicon ingot by carrying out cooling to molten silicon for keeping in the mould of molten silicon or container.Generally, generally adopt directional solidification method (Directional Solidification System is called for short DSS) stove crystal technique at present, adopt this technique can produce large square polysilicon silicon chip, reduce the cost of downstream battery processing.The growth furnace of directional solidification method is preferably adopted in the present embodiment.

Step S102: the top solid-state silicon raw material being loaded into described inculating crystal layer;

Do not limit the mode of loading described solid-state silicon raw material in the present embodiment, concrete mode of loading silicon raw material is determined according to the size of silicon raw material, as long as guarantee material to be reasonably loaded in container, and can ensure the safety of melt process crucible etc.

Step S103: described container is heated, melt described silicon raw material and the described inculating crystal layer of part, to form liquid level, solid-liquid interface is obtained between unfused inculating crystal layer and described liquid level, wherein, in this heat-processed, monitor the position of described solid-liquid interface, by the height of instruments monitor melt, at least keep the part inculating crystal layer contacted with described container bottom to be solid-state;

Wherein, this heat-processed is specially: heat described container, keep container top temperature higher than the fusing point of silicon, container bottom temperature is lower than the fusing point of silicon, form the thermograde perpendicular to container bottom, silicon raw material in described container and part seed crystal are melted from top to bottom successively, and retaining part inculating crystal layer is solid-state.

Adopt different polycrystal silicon ingot growth furnace, the method that described container heats also just is not quite similar, as adopted the growth furnace of heat-exchanging method, adopting the growth furnace of both the growth furnace of Bridgman method or employing combined technology, its heating means are had nothing in common with each other, as long as by solid-state silicon raw material and the fusing of part inculating crystal layer, the fusing demand of this step can be met.

For the growth furnace adopting directional solidification method casting polycrystalline silicon ingot, two groups of well heaters of the described container of usual employing (crucible) top and bottom heat silicon raw material, in order to melted silicon raw material as soon as possible, the temperature of crucible top should higher than the fusing point of raw silicon, in order to ensure in heat-processed, keep solid-state bottom inculating crystal layer, the temperature of crucible bottom should lower than the fusing point of seed crystal, and then the thermograde formed perpendicular to crucible bottom, silicon raw material is melted from top to bottom successively.

It should be noted that, the contact condition of solid-liquid interface and container bottom is not limited in this step, solid-liquid interface can have little angle with container bottom, or solid-liquid interface has a small amount of rough region, also can be parallel with container bottom, but in order to ensure the quality of the polysilicon produced, be preferably in the present embodiment, carrying out in heat-processed to container, keep solid-liquid interface or less parallel substantially parallel with described container bottom as far as possible, unfused seed crystal can be enable to occupy whole container bottom, and unfused part inculating crystal layer can stop that the oxygen impurities from container (crucible) bottom enters in molten silicon, to reduce the content of oxygen impurities in cast main body, the boron oxygen complex body formed is combined with the boron of doping as reduced oxygen impurities, to reduce the reduction coefficient of solar cell.

Step S104: control the thermal field in described polycrystal silicon ingot growth furnace, carries out crystallization to described liquid level and forms crystallizing layer, to make described solid-liquid interface move to the direction away from described container bottom, complete the growth of polycrystal silicon ingot.

Wherein, this process is specially: the power adjusting the heating installation of described container top and/or bottom, changes thermal field in stove, forms the thermograde perpendicular to container bottom, carry out crystallization to described liquid level, the temperature in described container is along going up gradually perpendicular to container bottom direction upwards.

When starting crystallization in the present embodiment, the thickness of solid seed crystal layer is 1mm-50mm, is preferably 5mm-30mm, is more preferably 20mm.

Similar with previous step, adopt different polycrystal silicon ingot growth furnace, the method cooled molten silicon is not identical yet, the refrigerating unit bottom growth furnace can be utilized to absorb heat, also can by reducing the mode of the power of growth furnace bottom heater, reduce the temperature of crucible bottom, make the thermograde that freeze profile becomes vertical with crucible bottom equally, to realize the crystallisation process from the bottom up of molten silicon, for the growth furnace adopting directional solidification method casting polycrystalline silicon ingot, the power of the concrete heating installation (being generally well heater) by adjusting described container top and/or bottom, change thermal field in stove, form the thermograde perpendicular to container bottom, crystallization is carried out to described liquid level, temperature in described container is along rising gradually perpendicular to container bottom direction upwards.In this process, described solid-liquid interface moves to the direction away from described container (crucible) bottom.

Carry out in crystallisation by cooling process to molten silicon in this step, due to the dephlegmation of impurity, impurity (as silicon carbide, silicon nitride etc.) in silicon raw material will be enriched in solid-liquid interface place, and foreign matter content in solid multi-crystalline silicon after crystallization is little, if but crystallization velocity is too fast, the impurity such as silicon carbide, silicon nitride can have little time fractional condensation and remain in solid-state polysilicon, becomes impurity enriched layer or the Hard Inclusion of pinning in crystal.

In order to avoid forming impurity enriched layer and Hard Inclusion because the speed of growth is too fast in the present embodiment, can to be tried one's best by the change of crystallization control temperature the speed of crystallization control, be unlikely to too fast to make crystallization velocity or excessively slow, specifically how control to determine according to the situation of production process.

The technical scheme that the embodiment of the present invention provides, the method of casting is adopted to produce polycrystal silicon ingot, inculating crystal layer is formed by laying big area seed crystal in advance at container bottom, the growth of monocrystalline silicon region is guided by seed crystal, make to comprise continuous large-sized monocrystalline silicon region in the polycrystal silicon ingot produced, the crystalline orientation of described monocrystalline silicon region is identical with the crystalline orientation of the described seed crystal be positioned at below it.

Spread in silicon raw material because the inculating crystal layer of bottom in castingprocesses has completely cut off the oxygen of container bottom, thus reduce the content of the oxygen in polycrystal silicon ingot, and, owing to containing large-sized monocrystalline silicon region in polycrystal silicon ingot, the chip area of crystal is large, corresponding grain boundary density just greatly reduces, therefore, the solar cell that the polycrystal silicon ingot adopting the embodiment of the present invention to provide is produced, monocrystaline silicon solar cell reduction coefficient more of the prior art is lower, and polysilicon solar cell photoelectric transformation efficiency more of the prior art is higher.

Embodiment two

In normal ingot casting process, after crystal growth completes, crystal need be cooled to certain temperature, from ingot furnace, remove polycrystal silicon ingot, for further processing to polycrystal silicon ingot afterwards.

As described in step 104 in embodiment one, the crystallization velocity of molten silicon can affect the quality of the finished product, the Hard Inclusion in product and impurity enriched layer can be reduced by the mode slowing down the speed of growth, but owing to starting the crystallization initial stage, the speed of growth of crystal compares and is difficult to control, for avoiding above-mentioned defect, therefore, the present embodiment is on the basis of embodiment one, further restriction is carried out to the process completing crystal growth in step S104 in Fig. 1, has described the detailed process that polycrystal silicon ingot is formed in detail.

See Fig. 2, control the thermal field in described polycrystal silicon ingot growth furnace described in the present embodiment, carry out crystallization to described liquid level and form crystallizing layer, to make solid-liquid interface move to the direction away from described container bottom, the process completing the growth of polycrystal silicon ingot specifically comprises:

Step S404: control the thermal field in described polycrystal silicon ingot growth furnace, carries out crystallization to described liquid level and forms crystallizing layer, move to make solid-liquid interface to the direction away from described container bottom;

Step S405: after described solid-liquid interface moves respective distance to the direction away from described container bottom, enters melt back crystallisation process, after at least performing once described melt back crystallisation process, obtains polycrystal silicon ingot;

By melt back crystallisation process, namely at certain growth phase, refuse (i.e. melt back) is carried out to the crystal after crystallization, can make to have separated out the impurity be deposited in solid crystals again to dissolve in the solution, in follow-up crystallisation process again, impurity continues fractional condensation again, and so forth, be equivalent to the fractional condensation time extending impurity to a certain extent, avoid impurity precipitation and be deposited in crystal, improve the quality of crystal.

It should be noted that, the present embodiment does not limit when which kind of degree crystallisation process proceed to and carries out melt back, also crystallization is again carried out after specifically not limiting melt back to which kind of degree, namely not limiting described solid-liquid interface, move respective distance to the direction away from described container bottom be how many, and described solid-liquid interface is how many to moving respective distance near the direction of described container bottom, as long as ensure that every subcrystalline height is greater than the height of melt back, namely described solid-liquid interface is less than the distance of described solid-liquid interface to the direction movement away from described container bottom to the distance of the direction movement near described container bottom, to ensure that crystal is in growth conditions.

In addition, do not limit the time that each melt back starts in the present embodiment, also do not limit the number of each melt back and the number of times of melt back, the crystal growing process namely in the present embodiment can have multiple, is described below to the process of crystal growth in the present embodiment.

One is when molten silicon crystalline growth is to certain altitude in step s 404, carry out a methback process, solid-state crystalline silicon is made to carry out secondary fusion, the height of fusing is less than the height of growth, when after melt back to certain altitude, carry out secondary crystal process, make the temperature in growth furnace maintain lower level always, until polycrystal silicon ingot has grown, as shown in Figure 3, this process is crystallization-melt back-crystallization, until grown, wherein, Fig. 3 a is the view before described silicon crystal crystallization, Fig. 3 b is the view of described silicon crystal on the basis of Fig. 3 a after crystallization, Fig. 3 c is the view of described silicon crystal on the basis of Fig. 3 b after melt back, Fig. 3 d is the view of described silicon crystal on the basis of Fig. 3 c after crystallization, illustrate in Fig. 3: silicon liquid 91, solid-liquid interface 92, silicon crystal 93 and crucible bottom 94.In figure, h1, h2, h3, h4 represent the height of silicon crystal described in Fig. 3 a ~ Fig. 3 d respectively, then the pass between the height of silicon crystal described in Fig. 3 a ~ Fig. 3 d is h4 > h2 > h3 > h1; Two is the circulations first passing through melt back crystallisation process several times, after making the growth certain altitude of crystal step, reduce in-furnace temperature always, crystal is made to continue crystallization, namely solid-liquid interface is advanced along the direction away from container bottom always, until complete the process of growth of polycrystal silicon ingot, this process is after multiple process, crystallization always, until grown; Three is carry out melt back-crystallisation process in the process of growth of whole crystal always, and this process is for repeat crystallization-melt back-crystallisation process always, until silicon ingot has grown.Specifically select which kind of crystal growing process above-mentioned, be not specifically limited in the present embodiment, the foundation of selection should be under the prerequisite of the quality ensureing polycrystal silicon ingot as far as possible, saves the time of crystal growth and required energy waste.

Polycrystal silicon ingot is formed owing to adopting the mode of repeatedly melt back crystallization in the present embodiment, be equivalent on the whole slow down the setting rate of crystal and the fractional condensation speed of impurity to a certain extent, make impurity (as silicon carbide, silicon nitride etc.) there is time enough and fractional condensation can be carried out fully, even if the impurity of separating out in advance, in follow-up methback process, also can again be dissolved in silicon liquid, thus avoid impurity and be deposited in the crystalline region solidified, and then the foreign matter content decreased in cast main body, improve minority carrier life time, thus improve the electricity conversion of solar cell.

Embodiment three

The manufacture method schema of polycrystal silicon ingot disclosed in the present embodiment as indicated at 4, with above two embodiments unlike, in the present embodiment, the selection of described seed crystal, the generation type of inculating crystal layer and the process of loading silicon raw material are specialized, only be described for the method for embodiment two in Fig. 4, certainly, method in the present embodiment also can be applied in the method for embodiment one, and the method for the present embodiment comprises the following steps:

Step S201: the container bottom in polycrystal silicon ingot growth furnace, the seed crystal splicing tiling adopting crystalline orientation identical forms described inculating crystal layer, and described inculating crystal layer is substantially parallel with described container bottom;

Be preferably the silicon single crystal tiling adopting (100) orientation in the present embodiment and form described inculating crystal layer, preferably, the area of described inculating crystal layer occupies the per-cent of described container bottom area, the per-cent that the volume of the monocrystalline silicon region namely in the final polycrystal silicon ingot formed accounts for polycrystal silicon ingot cumulative volume is 50%-99%, preferred, the area of described inculating crystal layer occupies the 70%-99% of described container bottom area, preferred, the area of described inculating crystal layer occupies the 90%-99% of described container bottom area, preferred, the area of described inculating crystal layer occupies the 95%-99% of described container bottom area.

Concrete, the seed crystal in the present embodiment the arrangement mode of container bottom vertical view as shown in Figure 5, the shape of the seed crystal in the present embodiment is preferably the geometrical shape of rule, is more preferably rectangle, is more preferably square.In conjunction with the shape of growth furnace and container bottom, for square, the inculating crystal layer after paving is completed also for square in the present embodiment, due to the restriction of paving mode, inculating crystal layer can not occupy the entire area of container bottom, preferably, each limit of inculating crystal layer formed by silicon single crystal 21 paving of (100) orientation in the present embodiment and the distance of container edge are similar to, to ensure monocrystalline silicon region in polycrystal silicon ingot evenly.

Step S202: the top short grained silicon raw material being loaded into described inculating crystal layer, to fill the gap between described seed crystal and the gap between described inculating crystal layer and described container side wall;

Owing to adopting the seed crystal paving of fritter to form inculating crystal layer in the present embodiment, consider in paving process and in the position of splicing seams and gap can be there will be between inculating crystal layer and container side wall, in castingprocesses, these gaps easily cause occurring the defects such as cavity in cast main body, thus affect quality product, adopt the blind of short grained silicon raw material, the cavity blemish in cast main body can be avoided on the one hand, the foreign gas in gap can also be got rid of, to reduce swirl defect and various oxygen triggering holes etc., and can utilize small-particle silicon raw material there is larger specific surface area, comparatively easily endothermic melting advantage, blind, can better stop the impurity such as the oxygen of container bottom.

Step S203: the top silicon raw material of large volume being loaded into described small-particle silicon raw material, until container (crucible) is filled, namely completes the loading process of silicon raw material.

The laden schematic diagram of silicon raw material is completed as shown in Figure 5 and Figure 6 in the present embodiment, Fig. 5 is vertical view, Fig. 6 is sectional view, the inculating crystal layer formed by silicon single crystal 21 paving of (100) orientation in figure is surrounded by silicon raw material 22, Fig. 4 is sectional view, is short grained silicon raw material 24 above inculating crystal layer 23, then top is the silicon raw material 26 of large volume, not directly and the sidewall contact of crucible 25, the gap between the sidewall of inculating crystal layer 23 and crucible 25 has small-particle silicon raw material 24 to fill to inculating crystal layer 23.

Perform step S204-step S206 afterwards, melt-crystallization-melt back crystallisation process to described silicon raw material and part inculating crystal layer, the step S103-step S105 in this process and a upper embodiment is similar, repeats no more here.

Below for the production process of the polycrystal silicon ingot of a concrete size, the manufacture method of the polycrystal silicon ingot in the present embodiment is described in detail.

Choose the silicon single crystal rod of (100) crystalline orientation, be processed into the short square rod that the length of side is 30mm, to after its cleaning, drying as seed of single crystal silicon.Prepare the square quartz crucible of standard of 840mm*840mm*420mm, interior spraying silicon nitride coating, so that seed crystal and crucible are kept apart, quartz crucible is placed on passive graphite base plate, then ready seed crystal is laid in crucible bottom, forms inculating crystal layer, in tiling process, keep the edge of (100) inculating crystal layer consistent with the distance of sidewall of crucible, and make the gap of surrounding be no more than 5mm-20mm, be preferably 10mm.Then according to the bulk silicon raw material that first load volume is less, and then load the order of bulk silicon raw material of large volume, the silicon raw material of about 400kg is filled up crucible, and the doping agents such as the boron of period interpolation some amount or phosphorus, can reach target resistivity to make the silicon ingot of production.

Then two groups of well heaters of crucible top and bottom are utilized to heat silicon raw material, make head temperature about 1550 DEG C (specifically arranging under particular case), and control the fusing point of bottom temp lower than silicon, form the thermograde perpendicular to crucible bottom, such silicon raw material just melts from top to bottom successively, and keeps solid-liquid interface substantially parallel with crucible bottom.By the height of instruments monitor melt, until seed portion melts, do not melt the height thickness of solid seed crystal layer (when namely the starting crystallization) and, at 1mm-50mm, be preferably 5mm-30mm, when being more preferably 20mm, reduce the heating power of top and bottom, in-furnace temperature is reduced, melts silicon with crystallization from the bottom up, due to the adductive crystallization of seed crystal, newly-generated crystal, by according to the crystalline orientation consistent with seed crystal growth, forms monocrystalline silicon region.

After a segment distance to be crystallized, control in-furnace temperature, make crystal melt back one segment distance of firm crystallization, and then crystallization, then melt back ..., step growth in this way, until complete crystal growth, then cools silicon ingot.Due at the beginning of crystal growing process, namely crystal grows according to the direction of seed crystal, therefore crystal above seed crystal by multiple have form with the monocrystalline silicon region of seed crystal crystalline orientation always, just in the region of adjacent sidewall of crucible, there is the polysilicon region that orientation is random.

Crystal growing process in above specific embodiment and crystalline size can not as the restrictions to the present embodiment method juche idea.

The sectional view of the polycrystal silicon ingot adopting the method for the present embodiment to produce as shown in Figure 7, the middle portion of this polycrystal silicon ingot is monocrystalline silicon region 31, monocrystalline silicon region 31 has consistent crystalline orientation with the seed crystal below it, around monocrystalline silicon region 31, because in sidewall of crucible 32, impurity is more, the very easily reason of nucleation, therefore around monocrystalline silicon region 31, the random polysilicon region 33 of crystalline orientation is formed, unfused inculating crystal layer 23 is also had in crucible bottom, between the seed crystal due to paving, there is gap, what fill between gap is short grained silicon raw material, thus there is crystal boundary 34 between the monocrystalline silicon region 31 of the polycrystal silicon ingot produced, but because the chip area of monocrystalline silicon region 31 is large, therefore, polycrystal silicon ingot more of the prior art, the density of the crystal boundary 34 of the polycrystal silicon ingot made in the present embodiment greatly reduces.

Embodiment four

With a upper embodiment unlike, in the present embodiment, the paving mode of inculating crystal layer is different with the selection of seed crystal, and in the present embodiment, the crystalline orientation of seed crystal is different.As shown in Figure 8, the method comprises the following steps the schema of the castmethod of polycrystal silicon ingot disclosed in the present embodiment:

Step S301: adopt the seed crystal splicing paving with first crystal orientation, cover the subregion of described container bottom, form the seeded region with first crystal orientation;

Step S302: adopt the seed crystal with the second crystalline orientation to cover the subregion of described container bottom, form the seeded region with the second crystalline orientation, described there is first crystal orientation seeded region and the described seeded region with the second crystalline orientation jointly form described inculating crystal layer, described inculating crystal layer is substantially parallel with described container bottom, wherein, the described seeded region with first crystal orientation is surrounded by the described seeded region with the second crystalline orientation, the orientation of first crystal described in the present embodiment is different from the second crystalline orientation, the two all desirable (100), (110) one or in the crystalline orientation such as (111),

Step S303: the top short grained silicon raw material being loaded into described inculating crystal layer, to fill the gap between described seed crystal and the gap between described inculating crystal layer and described container side wall, this step is similar with a upper embodiment, is not repeating;

Step S304: the top silicon raw material of large volume being loaded into described small-particle silicon raw material, until container (crucible) is filled, namely completes the loading process of silicon raw material, this step is similar with a upper embodiment, is not repeating.

Perform step S305-step S307 afterwards, melt-crystallisation process to described silicon raw material and part inculating crystal layer, the step S204-step S206 in this process and a upper embodiment is similar, repeats no more here.

The seed crystal of silicon single crystal as first crystal orientation of (100) crystalline orientation is preferably adopted in the present embodiment, adopt the seed crystal of silicon single crystal as the second crystalline orientation of (110) crystalline orientation, concrete paving effect as shown in Figure 9, the shape of the seed crystal in the present embodiment is preferably the geometrical shape of rule, be more preferably rectangle, be more preferably square.In conjunction with the shape of growth furnace and container bottom, for square, the inculating crystal layer after paving is completed also for square in the present embodiment, wherein, (100) silicon single crystal 21 of crystalline orientation occupies the region intermediate of container bottom, preferably, the edge of the seeded region formed by silicon single crystal 21 paving of (100) crystalline orientation is substantially identical with the distance of container edge, (110) seeded region that silicon single crystal 41 paving of crystalline orientation is formed surrounds the seeded region formed by silicon single crystal 21 paving of (100) crystalline orientation, preferably, the edge of the seeded region formed by silicon single crystal 41 paving of (110) crystalline orientation is substantially identical with the distance of container edge, to ensure monocrystalline silicon region in polycrystal silicon ingot evenly.

Certainly, do not limit the crystalline orientation of the seed crystal of regional in the present embodiment, to be only described for the scheme of silicon single crystal to the present embodiment of the silicon single crystal of (100) crystalline orientation and (110) crystalline orientation above.

The sectional view of the polycrystal silicon ingot adopting the method for the present embodiment to cast out as shown in Figure 10, the middle portion of this polycrystal silicon ingot is the monocrystalline silicon region 51 of first crystal orientation, (100) crystalline orientation is preferably in the present embodiment, the monocrystalline silicon region 51 of first crystal orientation has consistent crystalline orientation with the seed crystal below it, the monocrystalline silicon region 52 of the second crystalline orientation surround first crystal orientation at monocrystalline silicon region 51, it is the random polysilicon region 33 of crystalline orientation around the monocrystalline silicon region 52 of the second crystalline orientation, unfused inculating crystal layer 23 is also had in crucible bottom, between the seed crystal due to paving, there is gap, what fill between gap is short grained silicon raw material, thus there is crystal boundary 34 between the monocrystalline silicon region 51 of the polycrystal silicon ingot produced.

Due to the diffusion of crucible impurity; the edge nucleation site of sidewall of crucible 32 is more; the polycrystalline crystal that easy formation is more; therefore at the seed crystal periphery of (100) crystalline orientation; surround the seed crystal in other crystal orientation; define a protection border; the polycrystalline preventing periphery unordered is occupied the growth district of inner silicon single crystal; make that the silicon chip that finally obtains has the crystalline areas with (100) crystalline orientation (i.e. target orientation) as much as possible; and comprise the least possible crystal growth direction, thus ensure that the quality of the finished product.

Embodiment five

The manufacture method of polycrystal silicon ingot disclosed in the present embodiment and above-described embodiment unlike, the single crystal seed of inculating crystal layer is laid in the present embodiment, several seamed edge surperficial thereon and edge, along inclined direction excise certain degree of depth, form the polyhedron that bottom has regular shape, top is the seed crystal of boss structure, is spliced into inculating crystal layer.

Due to the splicing seams region of inculating crystal layer, grow into polycrystalline than being easier to, in follow-up process of growth, poly-region extends and expansion, can occupy the growing space of monocrystalline silicon region.And during the manufacture method growing crystal of the polycrystal silicon ingot utilizing the present embodiment to provide, the solid-liquid interface of localized indentation can be formed in splicing seams region.Because the direction of crystal growth is perpendicular to solid-liquid interface, both sides seed crystal will grow towards the area preference of splicing seams, thus suppress the growth of poly-region, to reduce seed crystal splicing seams adverse effect.

It should be noted that, if the described inculating crystal layer bulky single crystal seed crystal that to be a monoblock substantially identical with container bottom size and shape, during the manufacture method growing crystal of the polycrystal silicon ingot so utilizing the present embodiment to provide, the solid-liquid interface of localized indentation can be formed in edge slot region.Because the direction of crystal growth is perpendicular to solid-liquid interface, edge seed crystal towards the area preference growth that there is gap, thus the growth of poly-region will be suppressed, contribute to the growth of silicon single crystal.

Embodiment six

The manufacture method of polycrystal silicon ingot disclosed in the present embodiment and above embodiment unlike, inculating crystal layer in the present embodiment is the block slab that the monoblock under cutting from described polycrystal silicon ingot main body is identical with silicon ingot cross-sectional dimension, described polycrystal silicon ingot contains the large-sized monocrystalline silicon region of continuous print, and the crystalline orientation of described monocrystalline silicon region is identical with the crystalline orientation of the described seed crystal be positioned at below it.After cleaning up, as the inculating crystal layer of new cast main body, as shown in figure 11, for the inculating crystal layer paving in the present embodiment complete after paving effect schematic diagram, the region intermediate of container bottom is the block slab cut down from polycrystal silicon ingot, also referred to as overall seed crystal, this overall seed crystal periphery is equipped with the silicon raw material of fritter, to fill up the gap between overall seed crystal and container inner wall.

Below in conjunction with Figure 11, for the polycrystal silicon ingot produced in embodiment three, the manufacture method of the polycrystal silicon ingot in the present embodiment is described in detail.

According to the polycrystal silicon ingot containing monocrystalline silicon region that the method casting bed-plate dimension in embodiment three is 840*840mm, then the slab of next 840*840*30mm thickness of integral cutting in the main body of cast polycrystal silicon ingot, suitable polishing is carried out so that the laying of follow-up seed crystal to its side, afterwards chemical treatment is carried out to it, remove the impurity introduced in the course of processing, and thoroughly to clean up with pure water and after drying, as new inculating crystal layer.

Place it in the square quartz crucible of standard of 840mm*840mm*420mm, and after adding 400kg silicon raw material and the doping agent such as a certain proportion of boron or phosphorus, heat and monitor the position of solid-liquid interface, the seed crystal of silicon raw material and segment thickness is melted, and the seed crystal keeping crucible bottom to be about 20mm thickness keep solid-state.

Control the thermal field in growth furnace, the silicon raw material of liquid towards is lowered the temperature, make molten silicon along the crystallization from top to bottom of the direction perpendicular to crucible bottom segment distance, then heating makes crystalline silicon melt back one section of height, carry out the circulation of crystallization-melt back-crystallization successively with this order, until crystal growth to crucible 1/4 position, then continued down, keep the continual and steady crystallization of molten silicon, until crystal growth is complete.Due to the adductive crystallization of seed crystal, the crystal of growth is the polycrystal silicon ingot be made up of multiple big area monocrystalline silicon region, and wherein monocrystalline silicon region has the crystalline orientation identical with seed crystal.The similar of the polycrystal silicon ingot in the structure of the polysilicon adopting above method to cast out and embodiment three, repeats no more here.

It should be noted that, in theory, because the size of the inculating crystal layer in the present embodiment is close with container dimensional, and there is not the gap that paving is formed between seed crystal, therefore, when loading silicon raw material, directly can load the silicon raw material of bulk, but in actual production process, due to the needs that inculating crystal layer is placed, certain gap may be there is between inculating crystal layer and wall of container, therefore, when loading silicon raw material, also can determine whether need first to load short grained silicon raw material, with blind according to the situation in periphery gap.

Embodiment seven

With reference to Figure 12, the manufacture method of polycrystal silicon ingot disclosed in the present embodiment and a upper embodiment unlike, though the inculating crystal layer in the present embodiment is similarly one block under cutting from the described polycrystal silicon ingot main body block slab identical with silicon ingot cross-sectional dimension, after being cleaned, entirety puts into crucible, as the inculating crystal layer of new cast main body.But using block for monoblock slab as before seed crystal, need to carry out certain process to it, by several seamed edge and the edge of its upper surface, along inclined direction excise certain degree of depth, form the polyhedron that bottom has regular shape, top is the seed crystal of boss structure.

Due to the edge slot region of inculating crystal layer, grow into polycrystalline than being easier to, in follow-up process of growth, poly-region extends and expansion, can occupy the growing space of monocrystalline silicon region.And during the manufacture method growing crystal of the polycrystal silicon ingot utilizing the present embodiment to provide, the solid-liquid interface of localized indentation can be formed in edge slot region.Because the direction of crystal growth is perpendicular to solid-liquid interface, edge seed crystal towards the area preference growth that there is gap, thus the growth of poly-region will be suppressed, contribute to the growth of silicon single crystal.

Embodiment eight

With reference to Figure 13, the manufacture method of polycrystal silicon ingot disclosed in the present embodiment and a upper embodiment unlike, though the inculating crystal layer in the present embodiment is similarly one block under cutting from the described polycrystal silicon ingot main body block slab identical with silicon ingot cross-sectional dimension, after being cleaned, entirety puts into crucible, as the inculating crystal layer of new cast main body.But using block for monoblock slab as before seed crystal, need further to process it, after removing by the flaw-piece of its flaw-piece and periphery, position containing polysilicon region in the slab cut down, cutting has the groove of certain depth, like this when growing silicon ingot, the groove on inculating crystal layer is convenient to the solid-liquid interface forming localized indentation.Because the direction of growth of crystal is perpendicular to solid-liquid interface, therefore the seeded region on both sides will grow towards the direction in gap, thus inhibit the extension in subsequent growth process of polysilicon region in block slab and expansion, and then avoid the problem having influence on the crystal mass of subsequent growth due to the extension of poly-region and expansion.

It should be noted that, do not limit in the present embodiment to the shape of groove, just the profile of described groove can be square, also can be arc, is preferably V-arrangement or trapezoidal.

Embodiment nine

With reference to Figure 14, the manufacture method of polycrystal silicon ingot disclosed in the present embodiment and a upper embodiment unlike, in the present embodiment, above-mentioned block slab is cut into multiple fritter, and by the seamed edge of block for each fritter slab upper surface and corner, along a certain angle excision part, thus bottom being formed, there is regular shape, top is the shape of boss structure, then pieces block for multiple fritter slab together formation inculating crystal layer.

In order to process of deployment convenience and meet the needs of complete tiling, the well-regulated geometrical shape of the best tool of cross-sectional shape of block slab, the shape of preferred described block slab is rectangle, be more preferably square, larger block slab will be selected as far as possible, to make the gap pieced together between the seed crystal of formation the least possible, to ensure the quality of polycrystal silicon ingot.In addition, in order to better control making processes and the quality of described polycrystal silicon ingot, described inculating crystal layer should keep substantially parallel or less parallel with described container bottom.

The manufacture method of the polycrystal silicon ingot that the present embodiment provides is when crystal growth, splicing seams region will form the solid-liquid interface of localized indentation, again because the direction of growth of crystal is perpendicular to solid-liquid interface, the seed crystal on both sides will grow towards the orientation preferentially of splicing seams, inhibit the growth of poly-region, to reduce seed crystal splicing seams adverse effect.

The present embodiment the manufacture method of polycrystal silicon ingot is provided, not only solve and lay the high problem of the cost that brings of inculating crystal layer by single crystal seed, also solve by the problem being easy to polycrystalline extension and expansion caused by block slab laying inculating crystal layer, and be easy to lay, need not by auxiliary means.

Embodiment ten

The manufacture method schema of polycrystal silicon ingot disclosed in the embodiment of the present invention is as shown in 15, with each embodiment above unlike, the present embodiment is in melt process, the mode how controlling the inwhole fusing of seed crystal and the judgment mode when starting crystallisation process have been described in detail, and are namely illustrated the position how monitoring solid-liquid interface.The mode of the present embodiment can combine with each embodiment above.

Realizing adopting in the technology of single crystal seed casting polycrystalline silicon ingot, the inculating crystal layer laid bottom silicon material in vessels crucible and vessels crucible thereof is through the melt stage, seed crystal should melt, can not all melt again, but also will seed crystal be melted to a certain degree after the in good time crystallisation process that forwards to carry out crystal growth, become the difficult point of this technology, all do not relate in prior art and how specifically judge the degree that seed portion melts, and after the fusing degree of seed crystal reaches requirement, in time enter the technique and method turning crystallization.

The present embodiment has filled up the blank of above-mentioned technology, concrete, in the process melting described silicon raw material and the described inculating crystal layer of part, control the temperature of the base bottom below described container bottom between 1320 DEG C-1420 DEG C, the temperature controlling described upper vessel portion between 1450 DEG C-1600 DEG C, to form vertical thermograde in the above-described container.Described pedestal can be graphite base.

It should be noted that, ensure that the most direct mode that inculating crystal layer not exclusively melts keeps the temperature bottom the inculating crystal layer bottom vessels crucible lower than the fusing point of silicon, but in actual production, temperature bottom inculating crystal layer or the temperature bottom vessels crucible all directly can not be measured and obtain, and the temperature being positioned at the graphite base below vessels crucible can be measured really, but graphite base does not directly contact with inculating crystal layer after all, therefore, the temperature of graphite base can slightly larger than the fusing point of seed crystal, but can not be excessive.In the present embodiment between 1320 DEG C-1420 DEG C, at this temperature, can ensure that in the melt process before crystallization, inculating crystal layer is partial melting only, namely bottom inculating crystal layer, still have part seed crystal to keep solid-state.

Further, because the temperature thermal field in polycrystalline ingot furnace is uneven, its reason comprises: the uneven impact waiting various factors of vessels crucible bottom temp field, and the region of causing the temperature bottom vessels crucible to have is high, and some regions are low; Silicon material shape is indefinite, size differs, comprise the impact of the not equal various factors of laying method of inculating crystal layer, cause the actual whole fusing time of silicon material different in size, thus cause the actual melt time may exceed or be less than the default melt time, that is, after the melt phases-time preset completes, seed crystal bottom vessels crucible may not be fused to, or may all melt, and therefore determines the melt time and when enters the difficult point that crystallisation stage is also this technology.

By the temperature bottom graphite base is controlled between 1320 DEG C-1420 DEG C in the present embodiment, to ensure that vessels crucible bottom temp is under the melting temperature 1418 DEG C of silicon, and by controlling the well heater at ingot furnace top, the temperature on ingot furnace top is made to control between 1450 DEG C-1600 DEG C, thus form vertical thermograde in the above-described container, thus the fusing time of the silicon material of different positions is reached unanimity.

Further, known in conjunction with Figure 15, the thermal field in the present embodiment in the described polycrystal silicon ingot growth furnace of control, carries out also comprising before crystallization forms crystallizing layer to described liquid level:

Step S504: in the process melting described silicon raw material and the described inculating crystal layer of part, the position of monitoring solid-liquid interface, measures the height of solid-liquid interface, the height of solid-liquid interface monitoring device to solid-liquid interface can be adopted in the present embodiment to measure;

Step S505: when the height measuring the solid-liquid interface obtained is less than the thickness of described inculating crystal layer, start to carry out crystallization to described liquid level, namely start to control the thermal field in described polycrystal silicon ingot growth furnace, crystallization is carried out to described liquid level, solid-liquid interface is moved to the direction away from described container bottom.

The embodiment of the present invention by measuring the height of solid-liquid interface during melt, the height of unfused inculating crystal layer can be monitored the moment, thus melt time and the opportunity entering crystallisation process can be controlled accurately, preferably, when starting to carry out crystallization to described liquid level, the height of described solid-liquid interface is the 1%-80% of described inculating crystal layer thickness.The thickness of inculating crystal layer described in the present embodiment is preferably 10mm-100mm, first time, when starting crystallization, the thickness (i.e. the height of solid-liquid interface) of solid seed crystal layer was preferably 1mm-50mm, is more preferably, first time, when starting crystallization, the thickness of solid seed crystal layer was 3mm-30mm.

By the mode of above-mentioned control container bottom heating installation power, the temperature of the contact surface that described container bottom and described inculating crystal layer can be made to contact with described container bottom controls below the fusing point of silicon, thus in whole polycrystal silicon ingot making processes, ensure that inculating crystal layer can not melt completely, and by measuring the height of solid-liquid interface, the crystallization time opening can be determined accurately, thus the quality of seeding quality when ensure that crystal growth starts and subsequent crystallographic growth thereof.

Embodiment 11

Present embodiment discloses the polycrystal silicon ingot and the solar wafer adopting the polycrystal silicon ingot produced to make and solar cell that adopt the method for above each embodiment to produce.

Wherein, continuous large-sized monocrystalline silicon region that crystalline orientation is consistent is comprised in described polycrystal silicon ingot, after the impurity enriched layer at described polycrystal silicon ingot two ends is excised, cutting is carried out to other body region and obtains solar wafer, utilize described wafer fabrication solar cell, described solar cell comprises:

P-N junction in described wafer;

Conductive contact on described wafer.

Also comprise coating antireflective coating on the wafer in addition, to reduce the reflection of wafer to light, strengthen the absorption to light.

In polycrystal silicon ingot in the present embodiment, the content of oxygen, carbon and other impurity is all lower, and the defects such as grain boundary density reduce greatly, owing to having carried out good control to the Hard Inclusion in cast main body in production process, the defect concentration therefore in cast main body has also reduced greatly.

Because the wafer obtained has the consistent monocrystalline silicon region of the crystalline orientation of continuous large-area, therefore chemical process preferential etch pyramid matte can be adopted, good texture is carried out to wafer surface, increase the absorption to light, and, grain boundary density lower in wafer, effectively can avoid the defect that the photoelectric transformation efficiency of the solar battery sheet caused because the grain boundary density in material is too high is low.

In sum, relative to monocrystaline silicon solar cell of the prior art, solar cell in the present embodiment has lower reduction coefficient, and relative to polysilicon solar cell of the prior art, the solar cell in the present embodiment has higher photoelectric transformation efficiency.

Embodiment 12

Corresponding with embodiment ten, present embodiment discloses a kind of measuring apparatus of solid-liquid interface height, as shown in Figure 16 and Figure 17, the structural representation of the manual measurement device that Figure 16 provides for the embodiment of the present invention; Figure 17 is the cooperation schematic diagram of ratchet and pawl in manual measurement device.

The measuring apparatus that the embodiment of the present invention provides, for measuring the interface location of solid multi-crystalline silicon and liquid polysilicon in polycrystalline silicon ingot or purifying furnace, comprising:

The guide pipe 6 communicated with the furnace chamber of described polycrystalline silicon ingot or purifying furnace, this guide pipe 6 has see-through, and can observe out the position of gauge stick 9 in its inner chamber and orienting lug 8 in outside, when measuring apparatus does not work, orienting lug 8 is positioned at the top of guide pipe 6 inner chamber;

Be arranged on the winding box 1 on described guide pipe 6 top;

To be arranged in described winding box 1 inner chamber and to be wound with the roll 2 of wireline 5, this roll 2 connects two opposing sidewalls of winding box 1, and one end of roll 2 is run through the sidewall of winding box 1 and stretched out winding box 1, the roll 2 passing winding box 1 sidewall is connected with winding box 1 by tongued and grooved flanges 7;

Be positioned at described guide pipe 6, be connected with described wireline 5 and the gauge stick 9 in described furnace chamber can be deep into along with the unwrapping wire of described wireline 5;

Be arranged on and outside described winding box 1 and with described roll 2, be connected to control that described roll 2 rotates shakes wheel 4;

To be arranged on outside described winding box 1 and the ratchet 3 of locating with described roll 2 circumference and the ratchet 13 coordinated with described ratchet 3;

Be arranged on outside described guide pipe 6 to measure the measuring scale 10 of described gauge stick 9 miles of relative movement.

The working process of the measuring apparatus that the embodiment of the present invention provides is as follows:

When needing the interface location of solid multi-crystalline silicon and liquid polysilicon in polycrystalline silicon ingot or purifying furnace to measure, pull open the ratchet 13 blocking ratchet 3, shake wheel 4, the roll 2 in winding box 1 is made to rotate and drive gauge stick 9 by wireline 5, gauge stick 9 is declined in guide pipe 6 inner chamber and finally enters in the furnace chamber of polycrystalline silicon ingot or purifying furnace, after gauge stick 9 touches solid-state polysilicon, gauge stick 9 stops declining, the dropping distance of gauge stick 9 can be drawn by measuring scale 10, and finally determine the interface location of solid multi-crystalline silicon and liquid polysilicon; Reverse rotation is positioned at shakes wheel 4 outside winding box 1, gauge stick 9 is made to increase under the drive of wireline 5, after the top of gauge stick 9 rises to certain altitude in guide pipe 6, stop the rotation and shake wheel 4, unclamp ratchet 13, make it again block ratchet 3 and roll 2 cannot be made to rotate, gauge stick 9 cannot be declined because of deadweight, and measurement completes.

Can be drawn by above-mentioned working process, the measuring apparatus that the embodiment of the present invention provides, the interface location of solid multi-crystalline silicon and liquid polysilicon can be measured accurately, make subsequent operations more accurate, improve the qualification rate of product, perfect production technique.

Shake when gauge stick 9 rises or declines in the inner chamber of guide pipe 6, in the measuring apparatus that the embodiment of the present invention provides, also comprise the orienting lug 8 connecting described wireline 5 and gauge stick 9, the sidewall of this orienting lug 8 and the contact internal walls of described guide pipe 6 and both relatively sliding can occur.There is small gap between the outer side wall of orienting lug 8 and the inner side-wall of guide pipe 6 to slide in guide pipe 6 to allow orienting lug 8, also serve the effect preventing gauge stick 9 from rocking simultaneously, making the working effect of measuring apparatus better, avoiding thief rod 9 to contact with guide pipe 6 because rocking or liquid towards polysilicon impacts.

In order to optimize technique scheme further, in the measuring apparatus that the embodiment of the present invention provides, the bottom of described guide pipe 6 is provided with the water jacket 12 that can communicate with the furnace chamber of described polycrystalline silicon ingot or purifying furnace.When gauge stick 9 complete measure leave from liquid polysilicon after, the temperature of gauge stick 9 can be higher, after water jacket 12 is set, can make gauge stick 9 rising while just can cool, decrease cooling time, improve the work-ing life of gauge stick 9.

In order to strengthen the stability of measuring apparatus, in the measuring apparatus that the embodiment of the present invention provides, also comprise the stay-bolt 11 being evenly centered around outside described guide pipe 6 and two ends and being connected with the tongued and grooved flanges 7 at described guide pipe 6 two ends respectively.

Further, in the measuring apparatus that the embodiment of the present invention provides, described measuring scale 10 is arranged on described stay-bolt 11.Concrete, under the prerequisite not affecting normal work, measuring scale 10 can also be arranged on miscellaneous part.

Owing to needing the position observing gauge stick 9 and orienting lug 8 outside guide pipe 6, so guide pipe 6 will have see-through, in the measuring apparatus that the embodiment of the present invention provides, described guide pipe 6 is silica tube, concrete, guide pipe 6 can also be made up of other the material with see-through and thermotolerance.

The measuring apparatus that the present embodiment provides, when needs are measured, pull the ratchet blocking ratchet, roll can be rotated freely, when outside winding box, wheel is shaken in rotation, to be in winding box inner chamber and to take turns the roll be connected and can rotate thereupon with shaking, and then make gauge stick can when wireline unwrapping wire in guide pipe continuous decrease, after gauge stick touches solid multi-crystalline silicon, gauge stick stops declining, drawn the dropping distance of gauge stick by measuring scale, and then calculate the interface location between solid multi-crystalline silicon and liquid polysilicon; Counter-rotation shakes wheel, makes gauge stick increase and departs from the contact with liquid polysilicon, final after the top of gauge stick rises to certain altitude in guide pipe, stop the rotation and shake wheel, unclamp ratchet, make it block ratchet, and then gauge stick cannot be fallen because of deadweight, measurement completes.The interface location of solid multi-crystalline silicon and liquid polysilicon can be measured by measuring apparatus provided by the invention accurately, make subsequent operations more accurate, improve the qualification rate of product, perfect production technique.

Embodiment 13

Please refer to the structural representation of the self-operated measuring unit that accompanying drawing 18, Figure 18 provides for the embodiment of the present invention.

The guide pipe 06 communicated with the furnace chamber of described polycrystalline silicon ingot or purifying furnace, when measuring apparatus does not work, orienting lug 08 is positioned at the top of guide pipe 06 inner chamber;

Be arranged on the winding box 01 on described guide pipe 06 top;

To be arranged in described winding box 01 inner chamber and to be wound with the roll 02 of wireline 05;

Be positioned at described guide pipe 06, be connected with described wireline 05 and the gauge stick 09 in described furnace chamber can be deep into along with the unwrapping wire of described wireline 05;

Be arranged on outside described winding box 01, drive the rotation motor 03 that described roll 02 rotates;

To be arranged in described winding box 01 and to be passed by described wireline 05, and to control the vernier switch 010 that described rotation motor 03 stops when touching solid multi-crystalline silicon in the bottom of gauge stick 09;

Be arranged on outside described winding box 01 to measure described gauge stick 09 miles of relative movement and observed value to be converted into the encoder 04 of electrical signal;

Receive electrical signal that described encoder 04 sends and be shown as the indicating meter of observed value;

Control the controller that described rotation motor 03 is opened or stopped.

When needing the interface location of solid multi-crystalline silicon and liquid polysilicon in polycrystalline silicon ingot or purifying furnace to measure, rotation motor 03 is opened by controller, rotation motor 03 drives the roll 02 in winding box 01 to rotate and makes wireline 05 unwrapping wire, gauge stick 09 declines in guide pipe 06, when gauge stick 06 touches solid multi-crystalline silicon, gauge stick 06 stops declining, wireline 05 is no longer tightened and is relaxation state, originally closing condition is recovered after being lost pressure by the vernier switch 010 that wireline 05 is pushed down, and control rotation motor 03 and quit work, encoder 04 goes out the interface location of solid multi-crystalline silicon and liquid polysilicon according to the range observation that gauge stick 09 declines, and observed value is converted to electric signal transmission to indicating meter, again open rotation motor 03 by controller, make roll 02 reverse rotation and lifted completely by gauge stick 09 in guide pipe 06, when gauge stick 09 top rises to the certain altitude in guide pipe 06, close rotation motor 03 by controller, measurement completes.

Can be drawn by above-mentioned working process, the measuring apparatus that the embodiment of the present invention provides, when measuring the interface location of solid multi-crystalline silicon and liquid polysilicon, working process can not only be made more accurate, but also remote auto control can be realized, improve the production automation, make production process more simple, efficient.

Gauge stick 09 may shake when rising in the inner chamber of guide pipe 06 or decline, in order to avoid this situation occurs, in the measuring apparatus that the embodiment of the present invention provides, also comprise the orienting lug 08 connecting described wireline 05 and gauge stick 09, the sidewall of this orienting lug 08 and the contact internal walls of described guide pipe 06 and both relatively sliding can occur.There is small gap between the outer side wall of orienting lug 08 and the inner side-wall of guide pipe 06 to slide in guide pipe 06 to allow orienting lug 08, also serve the effect preventing gauge stick 09 from rocking simultaneously, making the working effect of measuring apparatus better, avoiding thief rod 09 to contact with guide pipe 06 because rocking or liquid towards polysilicon impacts.

Concrete, in the measuring apparatus that the embodiment of the present invention provides, the bottom of described guide pipe 06 is provided with the water jacket 012 that can communicate with the furnace chamber of described polycrystalline silicon ingot or purifying furnace.When gauge stick 09 complete measure leave from liquid polysilicon after, the temperature of gauge stick 09 can be higher, after water jacket 012 is set, can make gauge stick 09 rising while just can cool, decrease cooling time, improve the work-ing life of gauge stick 09.

In order to strengthen the stability of measuring apparatus, in the measuring apparatus that the embodiment of the present invention provides, also comprise the stay-bolt 011 being evenly centered around outside described guide pipe 06 and two ends and being connected with the tongued and grooved flanges 07 at described guide pipe 06 two ends respectively.

In order to optimize technique scheme further, in the measuring apparatus that the embodiment of the present invention provides, also comprise and be arranged on described stay-bolt 011, signal can be sent to described controller, control top limit switch 013 and bottom limit switch 014 that described rotation motor 03 quits work to prevent the excessive rising of described orienting lug 08 and decline.When orienting lug 08 rises to limit switch 013 place, top, top limit switch senses the position of orienting lug 08 and sends a signal to controller, and controller controls rotation motor 03 and quits work after receiving signal, and orienting lug 08 and gauge stick 09 stop rising; In the process that orienting lug 08 and gauge stick 09 decline, if gauge stick 09 occurs fractureing or damage the unforeseen circumstances making its length shorten, orienting lug 08 and the continual decline of gauge stick 09 meeting, when orienting lug 08 drops to limit switch 014 place, bottom, bottom limit switch 014 cuts out rotation motor 03 by controller, orienting lug 08 and gauge stick 09 stop declining, and avoid orienting lug 08 to drop in furnace chamber.

Preferably, in the measuring apparatus that the embodiment of the present invention provides, also comprise the gas interface 015 being arranged on described winding box 01 and can being filled with argon gas to the inner chamber of described winding box 01 and guide pipe 06.Constantly in the inner chamber of winding box 01 and guide pipe 06, argon gas is filled with by gas interface 015, high temperature gas flow in the furnace chamber of polycrystalline silicon ingot or purifying furnace can not be risen in measuring apparatus, the inner chamber of measuring apparatus can be kept to clean, extend the work-ing life of measuring apparatus.

Because guide pipe 06 communicates with the high temperature furnace chamber of polycrystalline silicon ingot or purifying furnace, so guide pipe 06 needs to have thermotolerance, in the measuring apparatus that the embodiment of the present invention provides, described guide pipe 06 is silica tube, concrete, guide pipe 06 can also be made up of other heat-stable material.

The device that the present embodiment provides, when needing to measure the interface location of solid multi-crystalline silicon and liquid polysilicon, rotation motor is started by controller, roll in winding box is rotated and drives the gauge stick in guide pipe to decline, when gauge stick touches solid multi-crystalline silicon, gauge stick stops declining, the wireline be connected with gauge stick is in the relaxation state do not stressed, vernier switch no longer recovers closing condition by the pressure of wireline, and then control rotation motor quits work, encoder stops meter long, now, observed value is the interfacial level of solid multi-crystalline silicon and liquid polysilicon, observed value is converted to electrical signal and is sent to indicating meter and demonstrates observed value over the display by encoder, restart rotation motor by controller, make roll reverse rotation increase to drive gauge stick, after the top of gauge stick rises to certain altitude in guide pipe, close rotation motor, measurement completes.When measuring the interface location of solid multi-crystalline silicon and liquid polysilicon by present embodiment, working process can not only be made more accurate, but also remote auto control can be realized, achieve the production automation, make production process more simple, efficient.

In this specification sheets, various piece adopts the mode of going forward one by one to describe, and what each some importance illustrated is the difference with other parts, between various piece identical similar portion mutually see.

To the above-mentioned explanation of the disclosed embodiments, professional and technical personnel in the field are realized or uses the present invention.To be apparent for those skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein can without departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention can not be restricted to embodiment illustrated herein, but will meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims

1. a manufacture method for polycrystal silicon ingot, is characterized in that, comprising:

Control the thermal field in described polycrystal silicon ingot growth furnace, crystallization is carried out to described liquid level and forms crystallizing layer, move to the direction away from described container bottom to make solid-liquid interface, complete the growth of polycrystal silicon ingot, this process is specially: the power adjusting the heating installation of described container top and/or bottom, changes thermal field in stove, forms the thermograde perpendicular to container bottom, carry out crystallization to described liquid level, the temperature in described container is along rising gradually perpendicular to container bottom direction upwards;

Thermal field in the described polycrystal silicon ingot growth furnace of described control, carry out crystallization to described liquid level and form crystallizing layer, to make solid-liquid interface move to the direction away from described container bottom, the process completing the growth of polycrystal silicon ingot is specially:

After described solid-liquid interface moves respective distance to the direction away from described container bottom, enter melt back crystallisation process, after performing repeatedly described melt back crystallisation process, obtain polycrystal silicon ingot;

Wherein, described melt back crystallisation process comprises, control the thermal field in described polycrystal silicon ingot growth furnace, melt back is carried out to described crystallizing layer, described solid-liquid interface is moved to the direction near described container bottom, afterwards, control the thermal field in described polycrystal silicon ingot growth furnace, crystallization is carried out to liquid level, to make described solid-liquid interface move to the direction away from described container bottom, described solid-liquid interface is less than the distance of described solid-liquid interface to the direction movement away from described container bottom to the distance of the direction movement near described container bottom;

Control the thermal field in described polycrystal silicon ingot growth furnace, carry out also comprising before crystallization forms crystallizing layer to described liquid level:

When the height measuring the solid-liquid interface obtained is less than the thickness of described inculating crystal layer, start to carry out crystallization to described liquid level;

Described is adopt the height of solid-liquid interface monitoring device to solid-liquid interface to measure to the mode that the height of solid-liquid interface is measured.

2. the manufacture method of polycrystal silicon ingot according to claim 1, is characterized in that, describedly carries out in heat-processed to described container, keeps described solid-liquid interface substantially parallel with the bottom of described container.

3. the manufacture method of polycrystal silicon ingot according to claim 1 and 2, it is characterized in that, in the process of described fusing described silicon raw material and the described inculating crystal layer of part, control the temperature of the base bottom below described container bottom between 1320 DEG C-1420 DEG C, the temperature controlling described upper vessel portion between 1450 DEG C-1600 DEG C, to form vertical thermograde in the above-described container.

4. the manufacture method of polycrystal silicon ingot according to claim 1, is characterized in that, when starting to carry out crystallization to described liquid level, the height of described solid-liquid interface is the 1%-80% of described inculating crystal layer thickness.

5. the manufacture method of polycrystal silicon ingot according to claim 1, it is characterized in that, the paving mode of described inculating crystal layer is: laid by the bulky single crystal seed crystal that a monoblock is substantially identical with container bottom size and shape and form, or be spliced by multiple fritter single crystal seed, or formed by the block slab laying under cutting from described polycrystal silicon ingot main body, described polycrystal silicon ingot contains the large-sized monocrystalline silicon region of continuous print, and the crystalline orientation of described monocrystalline silicon region is identical with the crystalline orientation of the described seed crystal be positioned at below it.

6. the manufacture method of polycrystal silicon ingot according to claim 5, is characterized in that, described inculating crystal layer is be spliced by the block slabs of the multiple fritters under cutting from described polycrystal silicon ingot main body.

7. the manufacture method of polycrystal silicon ingot according to claim 5, is characterized in that, described inculating crystal layer is laid by the block slab of the entirety under cutting from described polycrystal silicon ingot main body to form.

8. the manufacture method of the polycrystal silicon ingot according to claim 6 or 7, is characterized in that, the poly-region place on described block slab is cut with groove.

9. the manufacture method of polycrystal silicon ingot according to claim 8, is characterized in that, the profile of described groove is V-arrangement or trapezoidal.

10. the manufacture method of polycrystal silicon ingot according to claim 8, is characterized in that, described block slab be bottom for having the polyhedron of regular shape, top is the structure of boss.

The manufacture method of 11. polycrystal silicon ingots according to claim 5, is characterized in that, described seed crystal be bottom for having the polyhedron of regular shape, top is the structure of boss.

The manufacture method of 12. polycrystal silicon ingots according to claim 5, is characterized in that, described inculating crystal layer comprises the monocrystalline silicon layer of at least one crystalline orientation.

The manufacture method of 13. polycrystal silicon ingots according to claim 12, it is characterized in that, the process forming described inculating crystal layer is specially, and the seed crystal splicing tiling adopting crystalline orientation identical forms described inculating crystal layer, and described inculating crystal layer is substantially parallel with described container bottom.

The manufacture method of 14. polycrystal silicon ingots according to claim 1, is characterized in that, the process forming described inculating crystal layer is specially:

The manufacture method of 15. polycrystal silicon ingots according to claim 5, is characterized in that, the process that solid-state silicon raw material is loaded into the top of described inculating crystal layer is specially:

The manufacture method of 16. polycrystal silicon ingots according to claim 5, is characterized in that, the thickness of described inculating crystal layer is 10mm-100mm.

The manufacture method of 17. polycrystal silicon ingots according to claim 16, is characterized in that, when first time starts crystallization, the thickness of solid seed crystal layer is 1mm-50mm.

The manufacture method of 18. polycrystal silicon ingots according to claim 17, is characterized in that, when first time starts crystallization, the thickness of solid seed crystal layer is 3mm-30mm.

The manufacture method of 19. polycrystal silicon ingots according to claim 5, is characterized in that, the area of described inculating crystal layer occupies the 50%-99% of described container bottom area.

The manufacture method of 20. polycrystal silicon ingots according to claim 3, is characterized in that, described container is quartz crucible, silicon carbide crucible or silicon nitride crucible, and described pedestal is graphite base.

21. 1 kinds of solar cells, is characterized in that, adopt as right 1,2,4,5, the polycrystal silicon ingot produced of method according to any one of 7-20, this solar cell comprises:

P-N junction in described wafer;

Conductive contact on described wafer.