CN102312280A - Method and device for casting crystal material by using crystal selector - Google Patents

Abstract

The invention generally relates to a vertical directional solidification casting method using a crystal selection process, which is used for manufacturing a crystal material with a reserved crystal orientation and comprises a polycrystal material and a monocrystal material. When a traditional method for casting the crystal by using the crystal selection process is used for producing the crystal with a bigger size, the problems that the crystal selection effect is bad, a mixed crystal is easy to generate, the internal stress is high, the monocrystal material is hard to obtain or the expected quality requirement is hard to reach and the like exist. The problems are solved by the invention through providing a gradually-changed crystal growth area of which the horizontal cross section is gradually increased, thereby, a good crystal growth effect is obtained, and the obtained cast monocrystal or polycrystal material, such as silicon or silicon germanium, has fewer defects, high quality and a good performance, and is especially suitable for the application of the semiconductor field and the photovoltaic field.

Description

Use the crystalline material castmethod and the device of crystal selector

Technical field

The present invention relates generally to use vertical direction solidified cast method; For example vertical temperature gradient is solidified growing method (hereinafter is also referred to as the VGF method) or vertical bridgeman crystal growth method (hereinafter is also referred to as the VB method) or bigger silicon and the Si Ge crystal material of vertical Bridgman Stockbarger method (VBS method) manufacturing, especially is applicable to the polycrystalline and the monocrystal material of photovoltaic application.

Background technology

Should have most possibly based on the sensitive cell of crystal silicon (or claiming photovoltaic cell, solar cell) solar radiation power is converted into the efficient of electric current and permanent as far as possible work-ing life and rate of decay.This determines by multiple factor, the purity of silicon material for example, the type of silicon crystal (monocrystalline, polycrystalline) and defective, Impurity Distribution and crystal orientation, internal stress.Simultaneously, make the silicon crystal blank (entity) of large-size in the industry, can obtain higher production efficiency; And reduce the defective and the internal stress of silicon crystal, also help to improve the output capacity of finished product and non-defective unit.

Known in the type of silicon crystal, monocrystalline has the possibility that obtains the highest relatively electricity conversion than polycrystalline.Therefore, the apparatus and method of many manufacturing silicon single-crystal are used by a large amount of.Typically be exactly so-called single crystal pulling method, also be referred to as to cut krousky (CZ) method, utilize seed crystal to stretch in the silicon liquid of fusing,, obtain silicon single crystal rod at last through lifting the lasting crystal growth of seeding and silicon liquid liquid level top.Crystal bar during this method needs crucible usually and grows rotates relatively, thereby its producing apparatus relative complex, and technique controlling difficulty is bigger.Use the example of the method and apparatus of CZ manufactured silicon single crystal rod; Find in the one Chinese patent application that can be 200820080642.7 at application number, name is called the flexible axle monocrystaline silicon stove; More example; Comprise one Chinese patent application CN200810145905.2, CN200810162544.2, CN200710164263.6 and CN200810108276.6, or the like.For the full-time instruction to CZ method and manufacturing installation thereof is provided, the present invention quotes in full above-mentioned patents application documents at this.The CZ method can obtained performance than more excellent silicon single crystal idiosome; But also there are some significant disadvantages; Comprise its manufacturing installation and technology controlling and process more complicated, equipment and production cost are higher, are difficult to obtain the high quality single crystal idiosome (the second largest size of having only 20cm or 25cm usually) of large-size; Production efficiency is low; Exist bigger radially defective to comprise to cause stacking fault defect (or OSF ring defective) and thermal stresses dislocation, reach dopant density difference because of being difficult to overcome radial symmetry gradient in its crystal growth like swirl defect, oxygen, or the like.Similarly also have the floating region freezing method, or claim, but to have floating zone melting (FZ) and similar defect type of CZ method and deficiency in order to the polycrystalline silicon rod of growth.

For this reason; The service orientation freezing method, for example the vertical direction freezing method comprises that the method and apparatus of VGF (VGF method), vertical bridgman method (VB method) and vertical Bridgman Stockbarger method (VBS) manufacturing polycrystalline material idiosome is widely used in the production silicon crystal; With lower equipment cost and better simply technology controlling and process; Obtain large-sized polycrystal silicon ingot, improved production efficiency, reduced production cost.In VGF method crystal growth technique, the crystallization temperature gradient that is arranged in the thermal field that the immobilized heating unit forms is removable, and that crystal keeps is static.In VB method crystal growth technique, keep the immobilized heating unit to form crystallization temperature gradient immobilized thermal field, crystal moves therein.In VBS method crystal growth technique, the crystallization temperature gradient of heating unit and formation thereof is removable, and the crystal maintenance is static.The equipment of implementing these methods all includes crucible when using; It has diapire and sidewall at least; Formation can be held the container of the silicon liquid of silicon raw material and fusing; And with supporting thermal field system and the support system of crucible profile, comprise the heating unit of the silicon raw material in can heating crucible at least and keep the bracing or strutting arrangement of bushing position and shape.

Although obtain big size, high production efficiency and low production cost easily; Polysilicon has low carrier lifetime and relatively poor making herbs into wool effect because of its lower purity, less grain-size, more crystal boundary and lattice defect, the wafer processed; Lower by its battery sheet efficient of processing, be difficult to replace silicon single crystal.

For lower equipment with control cost down; Obtain higher efficiency of conversion; Some method and apparatus that can produce the bigger polycrystal silicon ingot of crystal grain, nearly silicon single crystal ingot based on VGF (VGF method), vertical bridgman method (VB method) and vertical Bridgman Stockbarger method (VBS) are developed, and quote in full here to specify some files of these method and apparatus: CN200810012354.2, CN200910152970.2, CN200920115886.9, DE10239104A1, CN200780002763.8, CN200810089545.9, CN 200780002753.4.Wherein, for obtaining well-grown crystalline structure, can induce the seed crystal of crystal growth to be introduced in the silicon raw material, or in crucible, set up some specific geometries.The use of these method and apparatus; Increased to a certain extent polysilicon grain-size, reduced lattice defect; Even can obtain nearly silicon single crystal ingot; But, exist still that technique controlling difficulty silicon ingot crystalline structure, defect and impurity big, that be difficult to guarantee stably to form expection are many, Impurity Distribution is uneven, the crystal ingot internal stress problem such as bigger and a large amount of seed crystals of needs consumption of wafer loss that is processed into bigger than normal.In addition, even using under the situation of a large amount of seed crystals,, also be difficult to obtain the high integrality single crystal because the preferential growth direction of seed crystal possibly depart from the single crystal growing direction, and partial melting, oxidation possibly take place.

Like many knowledges; Growing method based on VGF (VGF method), vertical bridgman method (VB method) and vertical Bridgman Stockbarger method (VBS); Can be used for growth such as single crystal such as sapphire, gallium arsenide; Therefore, also once be used for attempting the growing silicon single crystal material in early days, to be used for photovoltaic cell.Concrete grammar is to adopt the seed crystal revulsion, in VGF, VB or BVS method, in the bottom of silicon melt the silicon single-crystal seed crystal is set, and induces crystal growth with this, yet a lot of trials have all been failed, and the crystal of acquisition all is polysilicon bar none.

Summary of the invention

Therefore; The purpose of this invention is to provide a kind of use vertical direction freezing method; For example comprise that VGF or VB or VBS method make high-quality crystal entity, for example silicon crystal material idiosome (ingot) cheaply; Comprise the apparatus and method of polycrystal silicon ingot, silicon single crystal ingot or nearly silicon single crystal ingot that the crystal grain of low defective is bigger, wherein, particularly provide a kind of vertical direction freezing method of using to make the for example apparatus and method of silicon single crystal of high-quality crystal entity cheaply.

Method and apparatus of the present invention is applicable to various crystalline materials, below only is the example explanation with the silicon crystal.For other materials, only need can method and apparatus of the present invention be used to make the crystal entity of this material by corresponding adjustment control fusing of its fusing point and the temperature of solidifying.

The present invention also provides use vertical direction freezing method; For example VGF or VB or VBS method are made the high-quality silicon crystal material idiosome (ingot) with predetermined crystal orientation orientation cheaply, comprise the apparatus and method of polycrystal silicon ingot, silicon single crystal ingot or nearly silicon single crystal ingot that the big crystal grain crystal orientation of low defective is predetermined.Such crystal ingot in the process of silicon ingot being produced wafer, battery sheet, all has advantage at aspects such as cutting, making herbs into wool, is specially adapted to the making of high-quality sensitive cell with the crystal silicon battery sheet of silicon wafer and high photoelectric efficiency.

The present invention also provides a kind of use vertical direction freezing method; For example VGF or VB or VBS method are made the apparatus and method of large-sized silicon single crystal or nearly silicon single crystal idiosome cheaply; The crystal bar or crystal column, particularly the prism-shaped crystal that comprise the production larger diameter; With larger sized silicon ingot, the side's of comprising ingot, polyhedron shape ingot.The silicon single crystal idiosome that adopts apparatus of the present invention and method to produce, or by its single-chip of processing, than the monocrystalline of acquisitions such as CZ vertical pulling method; Has lower cost, impurity still less, resistivity distribution more uniformly; Lattice defect still less, for example oxygen cause stacking fault defect, swirl defect, thermal stresses defective, and more excellent making herbs into wool performance, p-n junction make efficiency more efficiently; Its photovoltaic cell sheet of processing has low cost and the more stable photoelectric transformation efficiency of Geng Gao; And, because lower crystal boundary impurity and defective, and have the longer work-ing life and the lower efficient rate of decay; Similarly, the polycrystal that adopts the inventive method and device to produce also is different from the polycrystal that vertical orientation clotting method such as common VGF is produced specifically, in above-mentioned each side significant advantage is arranged.Therefore; The present invention also provides a kind of large-sized silicon single crystal or nearly silicon single crystal, polycrystalline silicon material (entity); And silicon wafer and the photovoltaic cell processed by this material; The special crystal structure that they form because of its working method, Impurity Distribution pattern and good photoelectricity quality, and be different from common polysilicon or silicon single crystal.

The term that is adopted among the present invention " near silicon single crystal " or " near single crystal "; Be meant on such space successive crystal entity everywhere: it as a whole or its integral part; It surpasses on 50% the entity with upper volume and has consistent crystalline orientation, and for example, this nearly silicon single crystal can comprise the entity with the single crystalline silicon of polycrystalline adjacency; Perhaps it can comprise the silicon crystal of bigger continuous unanimity, and wherein less crystal is no more than 50% of TV.Nearly silicon single crystal can be preferably the less less crystal of ratio, for example, is no more than 25% or 10% or 5% less crystal.

The silicon crystal material that apparatus and method of the present invention are produced (embryo or ingot) is particularly suitable for having lower material purity and requires (6～8N) but the big photovoltaic of industrial scale is used crystalline silicon material.The present invention is used to produce photovoltaic and uses silicon crystal material, and when obtaining high photoelectric efficiency, cost that it is low and high production efficiency make photovoltaic generation realize that under large-scale application par becomes possibility.

On the other hand, as the congeners of silicon, germanium atom has the character similar with Siliciumatom, can be in silicon crystal lattice substituted for silicon.Germanic Germanium-doped silicon crystal or Si Ge crystal material below 50% can substitute and be close to pure silicon crystal and make photovoltaic cell, has good mechanical property, low eutectic point and high photoelectric properties.The present invention finds, method and apparatus of the present invention can directly be used to produce high performance Germanium-doped silicon crystal or Si Ge crystal material, especially single-crystal silicon Germanium alloy material or the nearly single-crystal silicon Germanium material that can be used for photovoltaic.When germanic 10% when following; The difference distribution of the germanium that segregation causes in crystal silicon can not form germanium basically and be dominant in the part; The present invention defines described Germanium-doped silicon crystal or mixes the germanium silicon crystal and is meant ge content at about silicon crystal below 10%, and silicon crystal also can comprise about germanium below 10%; The Si Ge crystal material then has about 10% or higher ge content.

The present invention is such realization: using the vertical direction freezing method; For example VGF (VGF method), vertical bridgman method (VB method) and vertical Bridgman Stockbarger method (VBS) are made in the device of silicon or sige alloy crystalline material; Setting has axial basically sidewall, the diapire that connects sidewall and the crucible that holds the silicon raw material at top; Wherein, on the diapire of crucible, include optional: spiral, apsacline, turnover type, dimensional constraints type, cucurbit serial type, semispiral type crystal selector from least one crystal selector position with next group crystal selector; Wherein, The crystal selector position is as the part of crucible diapire, constitutes crucible bottom with other parts of diapire jointly together with space near the crucible, and the crucible cavity at crystal selector position is arranged to be positioned at the minimum position of crucible bottom; Crucible keeps its position by the crucible bracing or strutting arrangement; Also be provided with the heating unit that contains at least one group of well heater; Wherein, Heating unit can form adjustable longitudinal temperature gradient thermal field in crucible when work; Silicon or SiGe melt in the crucible are begun to top consecutive solidification crystallization from the crystal selector position of crucible bottom, thereby obtain needed crystalline material.

Patent document CN99113400.1 has described the semispiral type crystal selector, quotes in full here so that its structure to be described.

Combine vertical direction solidified cast manufactured crystal with crystal selector, more in the field of alloy material application, but do not see that it is applied to cast silicon crystal, particularly photoelectricity and uses silicon crystal.The most key is that in the background technology, the horizontal section size of crystal selector is general to adapt with the crystalline body horizontal section size that is positioned at its top.And the relatively little a lot of crystal selector of usage level sectional dimension is realized the bigger crystalline body of level of growth sectional dimension, with the significantly raising of reduction that brings cost and production efficiency.

As device main body of the present invention, embodiment is to adopt directional freeze system's stove (DSS), for example, the HEM stove, i.e. heat-exchanging furnace is as the body of heater that holds crucible and control the fusing and the solidification and crystallization of the silicon material in the crucible.

Embodiment of the present invention uses described device to make the crystalline method, is that silicon that contains the suitable doping agent or sige alloy raw material are placed in the crucible, and the raw material that starts in the heating unit heating crucible makes it be fused into melt; Behind the optional maintenance appropriate time; The output of adjustment heating unit makes and produces longitudinal temperature gradient, the thermal field that forms and keep temperature to increase gradually to top from crucible bottom in the crucible; Through cooling melt is begun from the crystal selector position that is positioned at crucible bottom; With suitable speed solidification and crystallization upwards gradually, take out the crystal ingot that this solidifies, promptly obtain the crystalline material idiosome of the inventive method.Setting rate (moving speed on the freezing interface) is controlled at about 0.05～10mm/min in some embodiments, preferred about 0.1～1mm/min.Also can be according to the purity of thermograde and material, or the condition of solidifying, for example, whether apply the action of a magnetic field, or the requirement of production efficiency, and choose other suitable setting rate.This crystal idiosome is done suitable cutting and processed thin sheet or thick slightly tabular, promptly obtain p type or n type wafer or brilliant unit, p type or n type are determined by the advantage doping agent in the raw material; Optional to wafer thermal treatment, can improve the semiconducting behavior of wafer; Choose wantonly p type wafer is done the inhomogeneous doping of n type impurity or n type wafer is done the inhomogeneous doping of p type impurity; For example the shallow degree of depth of single face (reach approximately wafer thickness 1/100～1/2) is mixed; Acquisition contains the wafer of p-n junction; It can be used as silicon wafer or SiGe wafer that semiconducter device comprises photovoltaic cell, can further process the battery sheet by the photovoltaic cell blade technolgy, and and then processes photovoltaic cell.This crystalline material generally has neat lattice arrangement, and few relatively lattice defect is rendered as nearly monocrystalline or monocrystalline generally speaking, has favorable mechanical processing characteristics and good surface wool manufacturing performance.In process of setting, through the distribution and the way of output of adjustment heating unit, adjustment other around crucible can conduct heat or the structure and the distribution of adiabatic device, make maintenance isothermal in the inherent horizontal section arbitrarily of crucible, can obtain the more crystalline effect.

Among the present invention; Used silicon or SiGe raw material have and satisfy the for example purity that requires of photovoltaic cell of semiconducter device; And include maybe can mix proper amt comprise following listed those in order to set or to change one or more doping agents of its electricity or other performances, for example to be selected from: boron, aluminium, lithium, gallium, phosphorus, antimony, arsenic and bismuth.These doping agent total amounts can for 0.01ppma to about 2ppma (atomic quantity hundred several very much), preferred amount is such amount, the feasible slice resistivity of being processed by silicon is about 0.1 to about 50ohm.cm, is preferably about 0.5 to about 5.0ohm.cm.Doping agent can be directly and the mode of silicon or SiGe raw materials mix add, for example the mother alloy with boracic mixes with the HIGH-PURITY SILICON material, also can be originally just to contain in the raw material, for example, the silicon raw material that uses the boron that contains 0.01～1ppma is as the crystal growth raw material.The latter for example directly uses purity, and lower (6～8N) silicon is made photovoltaic and is used the crystal silicon material.

Usually as the brilliant respond well crystal selector of choosing; Its inner chamber particularly selects the overall dimension on the horizontal section of brilliant section less; Generally between 0.1～10cm, preferred 0.2～5cm, further preferred 0.4～2.5cm; For example optionally take from 0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,1.1,1.2,1.3,1.4,1.5,1.6,1.7,1.8,1.9,2.0,2.2, the size of 2.5cm, for example 2.8cm or 3.3cm again.And the horizontal section of the crucible main body cavity that crucible wall surrounds has bigger size, generally between about 25～200cm, for example, and about 35cm, about 50cm, about 60cm, about 75cm, about 90cm, about 100cm, about 110cm, or the like.In the method for the present invention, the horizontal sectional area at the place suitable for reading at described crucible crystal selector position is taken as horizontal sectional area (being the horizontal sectional area of crucible main body) about below 1/30 of the maximum that crucible wall surrounds usually; For example below 1/50, preferred about below 1/100, further preferred about below 1/400; For example about 1/500, about 1/1000, about 1/2000; About 1/8000, about 1/15000, or the like.Method of the present invention is because the ratio of bigger crucible main body horizontal section size and bigger crucible main body horizontal sectional area and crystal selector position horizontal sectional area suitable for reading can obtain high crystal manufacturing efficient.For example; Contrast is as the CZ method of another growth method of silicon single crystal, the about 25～30cm of crystal bar maximum horizontal section size that can obtain usually, and it is through crystal seed inductive crystal pulling growth; The crystal amount of growing in the unit time, the crystal amount that obviously can grow much smaller than method of the present invention.

Adopting device of the present invention to make silicon material direction solidifies; The crystal selector position is as the crucible lowest part, and solidification and crystallization will take place earlier melt therein, because crystal selector has the effect that forms monocrystalline of inducing; Therefore; Melt in the crucible will grow monocrystalline from the crystal selector position, and the continued growth that makes progress of the monocrystalline section of this monocrystalline above crystal selector is accomplished the solidification and crystallization single crystal up to the crucible all melts that is positioned at the crystal selector top; Thereby adopt apparatus and method of the present invention, can obtain the monocrystalline idiosome of silicon or SiGe.When crucible bottom is provided with the crystal selector more than 2 or 2; Each crystal selector position forms single crystal respectively; Each single crystal is also possible different in the crystal orientation that intersection possibly form dislocation, each single crystal, therefore, and the crystal idiosome that can obtain a plurality of single crystal and deposit.Among the present invention, used crystal selector comprises spiral, apsacline, turnover type, dimensional constraints type, cucurbit serial type, semispiral type crystal selector, can certainly choose the crystal selector of other types wantonly; Because different crystal selectors, it selects brilliant effect there are differences, even in solidifying, can form polycrystal; Therefore remaining melt of crucible induces the generation polycrystal; Therefore, the present invention also can obtain the polycrystalline material idiosome, but since crystal selector to the inhibition in mixed and disorderly crystal orientation and the selective action in advantage crystal orientation; Formed polycrystalline material generally has bigger crystal grain and the crystal grain arrangement mode that aligns mutually.Based on the characteristics of crystal selector itself, among the present invention, adopt spiral and semispiral type crystal selector; Tend to obtain high integrality monocrystalline idiosome, its crystal orientation also is preferable over < 100>or < 001 >, and acquisition is suitable for the crystal in the preferred crystal orientation of photovoltaic; But in the present invention; The crucible difficulty that manufacturing contains spiral crystal selector position is bigger, therefore, more preferably makes easier semi-spiral crystal selector.And use apsacline, turnover type, dimensional constraints type crystal selector, then tend to obtain polycrystalline idiosome or nearly monocrystalline idiosome, but its crucible is easy to manufacture; Cucurbit serial type crystal selector then tool has concurrently and is easy to obtain single crystal and makes simple advantage.

The applicant finds, adopts the crucible that contains spiral crystal selector position to make silicon single crystal, and minimum needs contain the spiral crystal selector position of half brilliant section of screw selecting, just can obtain single crystal.The brilliant section of half screw selecting here is meant that the spirochete of the brilliant section of choosing has only circle half, and the crystallization in the crystal selector position is climbed along the hand of spiral and revolved about 180 degree, just changes the monocrystalline section into.

In the apparatus and method of the present invention, a kind of embodiment is to adopt the crucible that only includes 1 crystal selector position, and preferably occupy crucible diapire central authorities, can simplify the manufacturing of crucible, and more easily obtain the monocrystalline idiosome.

One embodiment of the present invention are the junctions that the crystal selector position are arranged on crucible wall and diapire, and promptly sidewall also can be simplified the manufacturing of crucible to the turning point of diapire.

Because its size of crystal selector that common effectiveness is good is less; Cause the crystal selector position of crucible bottom less than crucible size; Particularly when making large-sized silicon wafer idiosome, the two-dimensional of the horizontal section of silicon wafer or crucible often will surpass more than the crystal selector lateral dimension several times, reaches usually more than 7 times; The horizontal section of the monocrystalline section of crystal selector position topmost; The horizontal section of the crucible main body that surrounds with crucible wall is compared, and has a bigger size sudden change, and this possibly cause crystal growth that bigger distortion takes place and form big stress; And possibly cause loftier turnover position to be easy to because of dissipating faster of heat energy generates new nucleus, destroy the crystalline reguarity.Simultaneously; The contriver finds; From the less sleeve pipe of the xsect that holds seed crystal of seed crystal revulsion position suitable for reading; Directly with the smooth diapire main part near right angle turnover continuity the into connection sidewall, this also is in the vertical direction freezing method, to use the seed crystal revulsion can't obtain the reason of large size silicon single-crystal before, like CN200920115886.9.Similarly; CN00121779.8 discloses passes through in crucible bottom the growing method that the big crystal of thermal conductivity begins growing part to be set; If also exist the crystal cross-sectional dimension of predetermined growth or the size of crucible body cross-section; When crystal begins the cross-sectional dimension of growing part, also be difficult to obtain the good crystal of quality.The contriver in depth analyzes the crystal growing process under the said circumstances; Find that this is because in the crystal growth of solidifying such as vertical direction such as VGF, VB, VBS (it is characterized in that not having transverse temperature gradient or radial symmetry gradient on the horizontal plane), the no doubt preferred solid-liquid interface place (being crystal-melt intersection) of crystal growth portion takes place; But; If the temperature in the same isothermal surface reaches the cold zero pour of mistake of melt, so, crystal growth also can occur in no solid-liquid interface simultaneously but form other melt positions of nucleus; For example, cause mixed and disorderly crystal growth near turnover position near flat crucible diapire.And this just from the no transition of crystal growth portion (solid-liquid interface is arranged) in less horizontal stroke (level) cross section expand the situation that crucible main body section (no solid-liquid interface) that the whole sidewall in big horizontal (level) cross section surrounds is taken place to.Even use seed crystal to induce, be near in the flat crucible basically, also can't guarantee to generate monocrystalline: turnover zone, often other zones of whole bottom, or the right angle of diapire and the crystallization simultaneously of monocrystalline upper area generate polysilicon.Therefore; The applicant finds, between the diapire of the bigger crucible main body in the less crystal growth portion in cross section and cross section, the connecting portion of transition gradually is set; Be transitional region, just become and keep the key of crystal growth in the crucible along solid-liquid interface, the crystal growth position growth that promptly formed.The arbitrary tangent of the bottom wall surface of described this transitional region with sidewall or horizontal plane, is the angle of inclination, and the contriver finds; The optimum value of this angle, relevant with the lattice parameter of silicon, with the difference in crystal orientation certain difference is arranged; Also relevant with thermograde and crystalline growth velocity, for adapting to this various conditions, can be preferably angle near 45 degree; For example, between about 15～75 degree, between preferred about 30～60 degree.

For this reason; In the apparatus and method of the present invention, preferably with the bottom wall portion of the monocrystalline section top that is positioned at the crystal selector topmost of crucible, processing with crystal selector is that the shape that is connected to sidewall is expanded, continued in sidewall and top obliquely gradually around the middle mind-set; Promptly form the zone of transition; From top to bottom, the horizontal stroke of this transitional region (level) cross section is from the size at monocrystalline section position, expands the size of the horizontal section that sidewall surrounds gradually to.This expansion continuity can be taked for example cambered outwards bowl-type, inwardly spill, single-order or the multistage truncated cone-shaped or the base structure of terrace with edge shape.Like this, the sidewall from the maximum transverse size of crucible bottom is extended to the crystal selector position; The crucible cavity demonstrates mild contraction; Perhaps when the transition zone is very little, eliminated the right angle turnover of diapire near crystal selector monocrystalline section at least, such structure can reduce the possibility that occurs distortion in the crystallization and gather big stress; Improve its mechanical property, and eliminate the thermal field drastic change of turning point, right angle; Simultaneously, described mild contraction, can also reduce other positions of crystal selector position and crucible divide a word with a hyphen at the end of a line near temperature controlled difficulty.Wherein, the continuity of diapire terrace with edge shape can easily be connected with the spiral crystal selector of same size, the terrace with edge shape monocrystalline section on half-spiral crystal selector top; And the cambered outwards bowl-type continuity of diapire mode, crucible manufacturing ratio is easier to; The regional volume that the continuity mode of the inside spill of diapire, concave surface surround is less, and the crystal idiosome special-shaped part that grows into is less, and utilization ratio is bigger; Truncated cone-shaped or terrace with edge shape are retracted to the crucible at crystal selector position, then have been in harmonious proportion the good and bad point of crucible manufacturing and crystal utilization ratio.

The height of above-mentioned transitional region of the present invention; Generally can be between about 0.5～30cm; Perhaps; Value is equivalent to crucible bottom place maximum transversal (or vertically) size, be between maximum sized about 0.1～2 times of horizontal section, with under the prerequisite of saving space and material, form appropriate tilt degree on the whole.

Opposedly with the above-mentioned diapire that contains transitional region be; By the axial basically place suitable for reading at crystal selector position, the direct cross break of sidewall of crucible also laterally continues to sidewall, lacks a tangible transitional region; When solidifying in such crucible; Only if very accurately the controlled temperature gradient comprises the radial symmetry gradient of setting up in the horizontal plane, otherwise be difficult to obtain the good crystal of quality; The example of another opposition is; Though the crucible diapire at the crystal selector position beyond with the zone of the similar transitional region of formation of convex surface or concave surface; If but the tangent plane of this curved surface and sidewall angle greater than 75 the degree, or less than 15 the degree, still be difficult to obtain effectively the good crystal of quality.

In the apparatus and method of the present invention; Other positions of the suitable for reading and diapire at crucible crystal selector position, for example described transitional region is connected the position of (dividing a word with a hyphen at the end of a line); Can look different aforesaid contraction mode from sidewall to the crystal selector position; And choose right cylinder, Rotary-table, prismoid, cubes, polyhedron, drum shaped body, cucurbit shape body structure, perhaps, from the monocrystalline section on crystal selector top; Press monocrystalline section shape suitable for reading or diapire from around in shape near monocrystalline section position suitable for reading, directly continuity connection.At the connecting portion of monocrystalline section to other positions of diapire; The narrow of a contraction can be set, and the crystal idiosome of processing is in the separation of rupturing easily of this narrow, like this; From crucible, take out this crystal idiosome main part more than narrow positions easily; And the crystalline material at reservation crystal selector position, during crucible use next time, the crystalline material of this reservation can reuse or be used as seed crystal.

The structure of crystal selector can include the brilliant section of initial section, choosing, monocrystalline section three parts that are connected successively from top to bottom usually.For example; Spiral crystal selector and semi-spiral crystal selector comprise the initial section of a non-helical shape; Usually be right cylinder, rectangular parallelepiped or prism, prismoid shape, or similar shape, the top of initial section; Being the spiral or the semi-spiral section in about 0.5～3 week, is the monocrystalline section that is right cylinder, prism or prismoid or tubular then.The crystal selector of cucurbit serial type, initial section that can type of including prismoid is at least one group of cucurbit string position of being made up of the narrow neck of shrinking and the portion of expanding then, is continued by part of expanding or narrow neck on top or expands into the monocrystalline section at last.Applicant's discovery, among the present invention, can be in the initial section of crystal selector; Place seed crystal (crystal seed), in the melted silicon material process, keeping the part at least of seed crystal is crystalline state; When solidifying,, induce position raw material melted crystalline growth on it with the part of the maintenance crystalline state of this seed crystal; Can strengthen selecting brilliant effect, or the acquisition specific crystal consistent with the seed crystal crystal orientation.Also can below the initial section of crystal selector, the seed crystal accommodating section of a prolongation be set, to make things convenient for the placement of seed crystal.A kind of special case of the embodiment of aforesaid use seed crystal of the present invention is brilliant section of choosing and a monocrystalline section of saving crystal selector, directly by the initial section of having settled seed crystal; The angled transition zone that the connection cross-section that makes progress increases gradually; Such mode can simplified construction, saves cost.As selection, can use the crystal bar that downcuts or otherwise obtain from the polycrystal silicon ingot of silicon single crystal or geometrical rule or crystal block as single described seed crystal.The use of seed crystal helps to control better crystal growth, makes the maximization of minority carrier lifetime and gettering, reduces textural defect simultaneously to greatest extent.

The size at crystal selector position is generally got height between about 1～30cm, and too high waste material and space prolong growth cycle, low excessively accurate controlled temperature gradient and the brilliant effect of the choosing that is difficult to obtain to expect of being difficult to.Each size of each section of crystal selector position, general difference is unsuitable excessive, and each size of initial section and monocrystalline section between about 0.3～3 times of the brilliant section of choosing corresponding size, is preferably got between about 0.5～2 times usually.Wherein, between the desirable about 0.5～20cm of altitude range of the brilliant section of choosing, preferred about 1～10cm, further preferred about 2～5cm; The desirable about 0.1～5cm of maximum transverse diameter scope of the brilliant section of choosing cavity, preferred about 0.2～3cm, further preferred about 0.5～1.5cm.

Corresponding with apparatus and method of the present invention; Crucible provided by the present invention; Can choose and be not easy to any high temperature resistant material that reacts with raw material; For example, as embodiment, crucible material can be chosen wantonly from graphite, silit, silit and combine silicon nitride, silicon nitride, quartz, aluminum oxide, zirconium white, quicklime, Natural manganese dioxide etc.Wherein, graphite or silit combine the crucible of silicon nitride material, can use repeatedly; The quartz crucible cost is lower; And the employing quartz ceramic crucible can be taked low temperature moulding technology, the crystal selector position that is easy to make crucible.Also can process the different piece of crucible by quartzy and quartz-ceramics, sintering or be welded together to form crucible integral body.For example, the crucible main body of quartz-ceramics matter and quartziferous crystal selector position, perhaps opposite.Wherein quartz crucible is many with the electroquartz manufacturing, when casting silicon uses, processes round shape usually, and quartz ceramic crucible can the compression molding sintering process be made, and can be made into square, round shape or other shapes.Crucible or quartz crucible, quartz ceramic crucible inwall can scribble releasing agent usually; Promptly; Has disengaging coating, to reduce pollution that crucible brings and the crystallization ingot is separated with crucible such as the densification of processing by silicon-dioxide, silicon nitride, barium carbonate or barium oxide or liquid sealing material.

The above main part in crucible wall of the present invention bottom, its horizontal section for optional from one of next group shape or proximate shape: circle, ellipse, trilateral, square, pentagon, hexagon, octagon, other Polygonss.

Among the present invention; The silicon raw material is added in the described crucible, and is placed on such as in VGF, VB or the VBS ingot casting device, and it is provided with heating unit and the bracing or strutting arrangement supporting with described crucible; Start heating unit; Silicon raw material in heating and the fusion crucible, and in crucible, set up the heat distribution (gradient temperature field) that temperature reduces gradually to the bottom from the top is through cooling sole crystal selector position actively or passively; Make molten silicon begin unidirectional and vertically upward lasting solidification and crystallization from the crystal selector bottom, up to accomplishing the silicon crystallization.

In another kind of mode of the present invention, seed crystal is at first placed the bottom initial section at crucible crystal selector position, and the silicon raw material is added in the described crucible subsequently; Crucible is to be placed on such as optional in the ingot casting device of VGF, VB or VBS method; It is provided with heating unit and the bracing or strutting arrangement supporting with described crucible, starts heating unit, mainly from top and upper lateral part heating crucible; Set up the heat distribution of vertical temperature gradient at crucible; Make the silicon raw material be heated and begin fusion from the top, the while is cooling sole actively or passively, thereby keeps the solid phase of the seed crystal of crucible bottom.During fusion, the melt stage of monitoring silicon (for example through around crucible is set, comprising near the thermopair that the initial section position is) is in order to follow the trail of and to control the position of solid-liquid interface.Making melt stage proceed to the part silicon seed is melted.In case the seed of single crystal silicon fusion of required part, melt stage finishes, and begins crystal growth phase through the described molten silicon of cooling in described gradient temperature thermal field.Make crystal growth in crucible, make progress unidirectional and vertically continue and carry out, up to accomplishing the silicon crystallization from the solid-liquid interface of seed crystal.

Another embodiment of the present invention is, the molten silicon of part at least is provided to the described crucible (or being called the silicon solidification crucible) that comprises the crystal selector position by the molten silicon generator from other setting, and and then therein by aforesaid mode solidification and crystallization.Wherein, a kind of mode is to replenish the silicon material through molten silicon generator to the silicon solidification crucible, thereby in a silicon solidification crucible, obtains more crystal silicon output with the deficiency that remedies the initial silicon material; Another kind of mode is that the molten silicon in the silicon solidification crucible mainly obtains from molten silicon generator.The example of molten silicon generator; Comprise to be heated that crucible for example maybe can and flow to the heating unit of silicon solidification crucible with the unsettled heat fused of silicon material with the fusing container of silicon material wherein; Or molten silicon provides conduit, and molten silicon directly provides conduit to be injected into the silicon solidification crucible from outside through molten silicon.This embodiment is that fusion separates with the solidification and crystallization system, is convenient to optimize better fusion and crystallisation step.In this way, the silicon material can be by fusing in advance, the slagging of its container top, and possible bottom runs off, and can improve the purity of solidifying initial silicon materials, and the generation that can partly walk abreast at least of fusion and the process of solidifying can be enhanced productivity.

Because the crucible that uses in the apparatus and method of the present invention, its bottom has the shape of more complicated, comprises the surface of the curved surface that is convex or concave; Or the surface on inclined-plane; And the crystal selector position that vertically is provided with, adopt common bracing or strutting arrangement with hither plane surface, be difficult to support crucible reliably; Bearing surface is little, and deformation possibly take place sidewall of crucible under the high temperature; Simultaneously, the object that the bracing or strutting arrangement conduct of crucible contacts with crucible, it will play heat conduction or heat-blocking action, influence the temperature distribution in the crucible.For this reason, among the present invention, bracing or strutting arrangement is designed to have the support zone that is curved surface that at least one can fit with part at least or most of curved surface outside surface of crucible diapire, supporting with this and described (silicon solidifies) crucible.Such bracing or strutting arrangement can obtain more reliable and more stable support effect, prevents the distortion of crucible diapire, and, can form the heat conduction of easy expection and control or the position of effect of heat insulation in crucible bottom, make that needed temperature control is more prone to realize when solidifying.

By such support zone; When keeping bushing position; The thermal field of crucible bottom can effectively be controlled heat radiation and adiabatic through the support zone of fitting with diapire and obtain better control, thereby make the raw material acquisition more crystalline effect near the crucible bottom of curved surface.

Above-mentioned bracing or strutting arrangement or itself and the crucible diapire support zone of fitting at least preferably adopt high temperature resistant and the material that the good heat conductive performance is arranged, for example graphite material, or the graphite material of having flooded silicon, or silit combines the silicon nitride material.Because graphite or silit have thermal conductive resin, through the bearing surface of this applying, heat carries out inside and outside exchange from crucible bottom through graphite matter support zone easily.Therefore, through the temperature of adjustment graphite matter support zone, just can control the temperature variation of crucible bottom more efficiently.

In the device of the present invention, the bracing or strutting arrangement of its crucible preferably also comprises the position or the structure that directly the crystal selector position are supported, and like this, the relatively weak crystal selector position that can reduce crucible deforms and damaged possibility.The position of such support or structure can be set to directly be supported on the bottom at crystal selector position; And/or around the crystal selector position, provide support; And the support zone that preferably will support the crystal selector position is arranged to controlled well heater; When providing support, the extra temperature function to the crystal selector regional area is provided also.

Bigger volume change takes place in silicon or SiGe when solidification and crystallization, at this moment, sidewall of crucible, particularly its crystal selector position that deformation is less, easy quilt bursts and causes not solidified high temperature silicon liquid to be revealed from crucible, damages crystal growing apparatus of the present invention.For this reason, among the present invention, described bracing or strutting arrangement can also include the cavity that holds the crystal selector position and can hold the cavity of the silicon liquid that possibly reveal; When bracing or strutting arrangement had the cavity that can hold the crystal selector position, even reveal at the crystal selector position, the silicon liquid of leakage solidification-stack rapidly stoped more and reveals in cavity.Simultaneously, have and allow in the cavity space of bracing or strutting arrangement of cavity apparatus for testing weeping is set, in time find leakage and report to the police.

For the direction of expecting in realization the inventive method is solidified, in the device of the present invention, its heating unit needs to form the crucible that comprises the crystal selector position thermal field of vertical temperature gradient.This can realize so as to one of following three kinds of modes at least: heating unit includes the well heater that is extended under the crucible wall extroversion with the same horizontal plane at least a portion position at crystal selector position; Heating unit includes the well heater of may command output, and it is formed on the thermal field of the VG temperature distribution of position, crystal selector position; Contain the well heater that is arranged near the may command output in crystal selector position, its control of passing through output is to form vertical temperature gradient at the crystal selector position.

Among the present invention; Can there be sizable size difference and differences in spatial location in the crystal selector position of crucible with other positions, and particularly with respect to the crucible main part, the crystal selector position protrudes in the crucible main body downwards; Has surface thermal radiation and thermal capacity much smaller than the crucible main body; And big radiation surface area and thermal capacity ratio, under same heat flux density (referring to the heat flux that certain cross-sectional unit area passes through), its intensification and cooling performance are totally different with the crucible body section.Therefore, the heating unit of vertical direction coagulation system of the present invention must be designed to form at the crystal selector position heat energy supply be different from the crucible body section especially, and must adapt with crucible bracing or strutting arrangement and optional heat insulation/adiabatic system.For this reason, a kind of optional mode is to reduce as the face well heater of heating unit and export corresponding to the power at crystal selector position.For improving the heating efficiency of heating unit; Improve the control accuracy of the thermograde at each position of crucible when solidifying, preferably at the crystal selector position area heating installation and/or refrigerating unit are set, wherein this area heating installation constitutes the part of whole heating unit; The area heating installation at this position; Can constitute the cage shell-like around the crystal selector position, or sleeve-like, or according to needed other shapes of the whole thermal field effect requirements of heating unit.The output of the power of the well heater at this crystal selector position can with other well heater synchronization control of heating unit, but preferred independent control.Wherein, this partial refrigerating unit also preferably is independent of other refrigerating unit control of bottom.

Among the present invention, the heating unit at crystal selector position can be integrated with the bracing or strutting arrangement of crucible diapire, and is integrated with refrigerating unit.For example, adopt the bracing or strutting arrangement of graphite to place the following support crucible that plays a part of crucible diapire, simultaneously, this graphite bracing or strutting arrangement is passed to heating current or applies the induction heating electric field, then constituted the bracing or strutting arrangement of tool well heater effect.When the energising heating; Heating makes its fusing to this well heater to the raw material in the crucible; And after withdrawing from or weakening heating current or electric field; Because the very high thermal conductivity coefficient of graphite material, the well heater of graphite can play the effect of soaking device, scatterer, makes the material solidification crystallization of fusing and makes latent heat of solidification derive and make the crystal cooling.

When adopting device of the present invention to make crystalline material,, can make the material part refuse of solidification and crystallization of crystal selector position for guaranteeing to generate single crystal; Crystallization once more, method are to start heating unit earlier and make the material melts that comprises the crystal selector position in the crucible; In crucible, form the material that has melted make in the crucible from the longitudinal temperature gradient that the crystal selector bottom begins to solidify, make the material solidification crystallization at crystal selector position, then; The output of adjustment well heater makes top, crystal selector position comprise the material refuse of having solidified of the brilliant section of part choosing, and it is solid-state that the bottom keeps, and in the crystal selector position, forms the melt of fusing again and the freezing interface between the crystalline solid; Adjust well heater output then; The freezing interface is moved from this position gradually,, moved to the place of dividing a word with a hyphen at the end of a line at other positions of crystal selector and crucible diapire on the freezing interface up to the whole solidification and crystallizations of the material at crystal selector position; After this; Continue to make the freezing interface to move on gradually by routine again, the surplus material to crucible all solidifies, and accomplishes crystal growing process.Through such processing, even adopt the crystal selector of the simple shape that selects brilliant poor effect, perhaps the size of crystal selector is bigger, also can obtain single crystal or nearly single crystal effectively.A kind of embodiment of this method comprises cold excessively (the Successiverelaxation of supercooling of continuous relaxation; SRs) method; It also has good reduction primary crystal impurity, improves the effect of crystal mass, is particularly suitable for the low slightly raw material of purity.

When the crystal selector position was higher, from the melt solidifying process of crystal selector bottom beginning, the time length was longer; For this reason; A kind of embodiment that the present invention also proposes is, after the raw material fusing in the transitional region of part at least on crystal selector position or crystal selector and top thereof, promptly from crystal selector bottom beginning process of setting; At this moment, other raw materials in the crucible since its quantity much larger than the crystal selector position and near transitional region in raw material and can all not melt.Like this, between melting period, process of setting has just begun even has accomplished crystal selector position and near crystal growth thereof, so, can shorten total setting time, shortens the production cycle in the major portion of raw material.

According to crystalline material manufacturing installation of the present invention, it holds the crucible that raw material and raw material melted are solidified therein, with the crucible that uses in the existing background technology, significant difference is arranged on the structure.Like the description of the file quoted in the background technology introduction, the device of existing manufacturing single crystal silicon material (czochralski crystal growing furnace), the crucible of use is round shape normally, and in the majority with quartzy material; When adopting directional freeze manufactured polysilicon, common available plumbago crucible, silicon nitride crucible, quartz crucible etc. also have cold crucible, process round shape or square basically, and its diapire is put down basically, or slightly is the cambered surface evagination with bigger radius-of-curvature.And among the present invention, used its diapire to contain the so comparatively complicated structure in crystal selector position, and the extreme lower position of crucible bottom is arranged to be in the crystal selector position.The specific spatial configuration at crystal selector position just; And choice of location, just make device of the present invention under the cooperation of corresponding heating unit and bracing or strutting arrangement, can be by process of setting longitudinally; Obtain low high performance monocrystalline of defective of large size or nearly monocrystal material, or the polycrystalline material of big crystal grain.The above-mentioned particular combination mode with crystal selector and common crucible that the present invention proposes comprises the transitional region structure that both are smoothly combined, and the novel crucible that obtains thus becomes the key of apparatus and method of the present invention.The contriver finds, quartz material, particularly quartz-ceramics material, since its good moulding, sintering and weldableness, the most suitable making crucible of the present invention.

In the method for the present invention, the crystallization velocity of silicon or SiGe and process control can be according to crystallization velocity general in common VGF, VB, the VBS method and process modes.For example, solidification and crystallization speed is taken at certain numerical value of about 0.02～30mm/ minute scope, and preferred about 0.1～8mm/ minute, further preferred about 0.2～2mm/ minute; In the solidification process control, initial solidification can be slow, gets into the monocrystalline section and can solidifying near at the end can be slow, perhaps, choose the setting rate of unanimity basically than slow solidifying of the bigger position of cross-sectional variation soon.Because crystal is grown along the intrinsic crystal face of both having deposited all the time in the inventive method, thereby can obtain to be higher than the speed of growth that common vertical direction is solidified casting ingot method, has improved production efficiency.

In the apparatus and method of the present invention, in order to obtain the crystalline structure of uniformity, particularly Impurity Distribution single crystal structure more uniformly better; With reduction crystalline impurity and defective content, also can be provided with the melt whipping appts, in the process of solidifying; Stir melt; Make melt in crucible, constantly do the rotation or back and forth wait motion, this motion of melt is three-dimensional motion in crucible; That is, comprise a kind of of following motion or its arbitrary combination at least: have horizontal direction rotation or to-and-fro movement component, rotation or to-and-fro movement component, have the component that rotatablely moves along certain center with vertical direction.This melt whipping appts acts on the melt part of raw material when solidifying, make bath movement, strengthens the heat transfer and the mass transfer of melt; Can make melt homogenizing and hot-fluid transmission preferably evenly quick, improve the homogeneity of melt, reduce Particulate Inclusion; Simultaneously, adjust the cold-zone of crossing at place, freezing interface, make to solidify and tend to equilibrium freezing more; Obtain best crystallization effect and the concentration and the distributional difference that reduce impurity in the crystal, thereby obtain the silicon crystal of the good and electrical property homogeneous of texture.

The caused bath movement of this melt whipping appts of the present invention; Its speed or back and forth/loop cycle should be lower; To avoid the disadvantageous effect (as destroying lattice, increasing nucleus, crystal boundary and defective etc.) to solidification and crystallization, particularly, the period of motion of generally controlling rotation or the to-and-fro movement component of liquation on a certain direction is at about 0.1～100 cycle per minute clock; Preferred about 1～50 cycle per minute clock, further preferred about 5～30 cycle per minute clocks.When movement velocity was higher, for example with high-frequency vibration, crystal grain diminished, and is unfavorable for single crystal growing.

Can use mechanical stirring device to serve as whipping appts of the present invention and realize stirring action liquation through starting this mechanical stirring device.For example, a kind of embodiment is to be provided with mechanical stirring device on the top of crucible; It contains at least one that can stretch in the silicon liquid that has melted and stirs position; After starting this whipping appts, this stirring position can be inserted in the liquation, with the reciprocal of certain frequency or the stirring silicon liquid that rotatablely moves.This stirring position can bring the high temperature material of pollution to process with suitable being difficult for, and for example, silit, graphite, silit combine silicon nitride, silicon nitride, quartz, aluminum oxide.

Another kind of embodiment is to use low frequency time-varying magnetic field whipping appts to serve as whipping appts of the present invention and realize the stirring action to liquation through starting this magnetic field whipping appts.The magnetic field that changes will produce lorentz's force in the melt of conduction, thereby will cause the motion of melt.The magnetic field time varying frequency of time-varying magnetic field whipping appts generally can be arranged in the scope of about 0.1～100 cycle per minute clock, preferred about 1～50 cycle per minute clock, and further preferred about 5～30 cycle per minute clocks, magneticflux-density is as the criterion can make the liquation sufficient movement.For different crucible diameter, different mode of motion, different raw materials composition (electric conductivity, density), different position of magnetic pole and spatial arrangement; And number of magnetic poles is different; Needed magneticflux-density is different; Can be according to condition of different; The corresponding method of calculation that provide according to prior art confirm, for example, patent document CN200380109279.7, CN200580048843.8 (quoting in full at this) have provided stressed some the corresponding calculated formula with kinematic parameter of the conductive melt in the magnetic field; Also can confirm through test.The advantage of the magnetic field whipping appts that uses among the present invention is to have the stirring position that directly contacts with liquation, can not bring extra heat, and setting and control are simple relatively.Can the magnetic field whipping appts be arranged on the crucible top; Perhaps around the crucible,, perhaps be arranged on the thermal insulation material outside, even be arranged on whole coagulation system periphery perhaps near other positions of crucible.Can adopt electromagnetic field generator as magnetic field of the present invention whipping appts, for example, use the coil of energising, perhaps can regard the closed galvanic circle of coil as, like the graphite loop, have cost low, control simple advantage.

According to the CZ method of routine, through from fused silicon pond, pulling out the crystal bar of cylindrical shape, because the rotational symmetry of crystal pulling, the radially intrinsic rotation in thermal gradient and the process, swirl defect encircles defective with OSF and all appears in the crystal bar of silicon single crystal.Polysilicon or silicon single crystal rod that the FZ method obtains have similar defective.On the contrary, can prepare silicon through method according to embodiments of the present invention, it can not show this swirl defect and OSF ring defective and other rotatory impurity striation defectives.Whole solidify with process of cooling in pass silicon ingot thermo-isopleth be that the defective of being introduced during the process of setting is distributed to randomly basically and does not receive to rotate on the growth interface that influences in the smooth process basically.Low-dislocation-density crystal silicon, the especially silicon single crystal and nearly silicon single crystal that can obtain thus not contain or be substantially free of swirl defect and do not contain or be substantially free of the OFS defective.It can easily obtain to have more heavy in section crystal ingot, and save seed crystal than FZ or CZ method growing single-crystal silicon, boosts productivity, and cuts down the consumption of energy.

Because the crystal selector shell has monocrystalline choosing crystalline substance and the function of inducing single crystal growing in some cases; In other cases; Has the effect that good column polycrystalline promotes and stray crystal suppresses; Therefore, the present invention has realized that crystal selector effect and direction are solidified crystal growth to combine, and has obtained to use such as vertical direction freezing method growing silicon single crystals such as VGF, VB, VBS or significantly improves the beneficial effect of polycrystalline quality.

Particularly, according to the present invention, the molten silicon of crucible solidifies since the initial part of the less crystal selector shell of xsect; And in the embodiment that uses seed crystal; Solidify from the top of seed crystal, even it grows into policrystalline silicon, will have also extremely that significantly few crystal grain and crystal boundary, bigger its are highly the highest can the same grain-size of growing with the vertical dimension of silicon ingot; And predetermined crystal orientation, and improved the speed of growth.Thus obtained polycrystal silicon ingot; Have crystal boundary specific rather than at random and specific (big) grain-size; And higher physical strength, have better suitable for making semiconductor components and devices and the photronic quality of polycrystal silicon ingot that obtains than common vertical direction freezing method.

Adopt apparatus and method of the present invention; Owing to can obtain perfectly crystal growth; Especially reduced crystal boundary and impurity, can use the raw material of the about 5N of purity and obtain good solar-grade silicon crystals, even under the certain situation; Under the situation that for example boron, phosphorus, aluminium are lower, the raw material that can use the about 4N of purity carries out crystal growth and the major part that obtains entity satisfies crystal idiosome or the crystal ingot that solar-grade silicon crystals requires.

Silicon ingot manufactured according to the present invention in the horizontal section upper dimension bound of (promptly with the vertical direction of crystal growth direction) only confirm by the manufacturing technology of direction coagulation system and crucible, be not to confirm by inventive method itself.Can produce according to the present invention and to have 1 size more than about 1m on the lateral dimension at least, and section area 1m2 and the crystal ingot of 4～8m2 at the most at least, comprise silicon single crystal ingot and nearly silicon single crystal ingot.Because the decision production cycle is crystal growth time vertically, makes the crystal ingot of big horizontal section size, can obtain higher production efficiency.Similarly, the upper limit of crystal ingot height maybe be relevant with long period, rather than relevant with the basis of manufacturing processed.About at the most 50cm to the ingot height of about 80cm even 100cm be possible.

Along the crystal ingot that suitable direction cutting is obtained, therefrom produce wafer, wherein, this wafer is suitable for manufacturing semiconductor element and sensitive cell, and bigger wafer can obtain higher sensitive cell manufacturing efficient and efficiency of conversion.Thus; The present invention also provides monocrystalline silicon piece or the nearly monocrystalline silicon piece with definite crystal orientation; And the polysilicon chip in bigger grain-size and the crystal orientation of confirming; It has less defects, comprises adulteratedly not containing or being substantially free of swirl defect and not containing or be substantially free of the OFS defective, have higher physical strength and workability and long minority carrier lifetime and work-ing life, and be fit to manufacturing semiconductor element and sensitive cell.

Single crystal rod of the present invention; The single crystal rod that more conventional CZ or FZ method obtain, shorter because of solidifying stroke, end to end between change in resistance less; Be used to make the photoelectricity wafer; Not only material use efficiency improves, and has reduced the technique controlling difficulty of subsequent disposal, is fit to produce in enormous quantities the wafer and the sensitive cell of uniform resistivity.

According to wafer of the present invention, the upper limit of its size is only confirmed by the size of crystal ingot provided by the invention and the manufacturing technology of wafer.Can produce the size that has at least 2 about 51mm (2 inches) above according to the present invention, for example about 25cm or about 35cm or about 45cm, and surface area 100cm at least ²And about at the most 0.3～1m ²Wafer.

The wafer that obtains further by photronic processes, is promptly obtained sensitive cell, and the battery that its more common silicon single crystal ingot is processed has high light energy use efficiency and work-ing life.

The invention provides a kind of sensitive cell thus; Comprise: the wafer that forms by successive crystal silicon entity of the present invention; This entity has the grain orientation of predetermined arrangement; Preferred copolar direction is perpendicular to the surface of this entity, and this entity further has optional separately at least 2 sizes that are at least about 11cm and at least about the 3rd size of 5.1cm (2 inches).This wafer further has at least 2 sizes that are at least about 50mm separately; P-n junction in the wafer; The ARC of choosing wantonly on the wafer surface; Optional one deck at least from back surface field and passivation layer; And the conductive contact on the wafer; The conductor wire that the transparent glass of optional encapsulated wafer and backboard and the conductive contact from wafer are drawn.Usually, the sensitive cell sheet that is made up of additional metal or the conductive contact of the identical polar on the sensitive cell are adjacent to each other into successive tape shape.

Similarly, the wafer that obtains further by the processes of other semiconductor components and devices, can be obtained other semiconductor components and devices, for example diode, triode, thyristor or the like.In these semiconductor components and devices, form at least one group of p-n junction in the crystal silicon, and include additional conductive contact or conductor wire/band.

The applicant finds, comprises among each embodiment of the present invention and the embodiment, and every use silicon materials are made crystalline, also is applicable to silicon materials and the silicon germanium material manufacturing crystal of mixing germanium.Adopt the present invention can make the silicon crystal of mixing germanium and the Si Ge crystal material that is fit to photovoltaic, for example, make the silicon crystal of mixing germanium of germanic about 0.5～5ppm; The silicon crystal of germanic about 5～10000ppm; Germanic about 1～10% silicon crystal, germanic about 10～49% Si Ge crystal, or the like.Wherein, adopt germanic plain metal silicon raw material, purified processing re-uses apparatus and method of the present invention and makes crystal, can not need add germanium, can directly obtain the silicon crystal of germanic about 0.5～5ppm.

Further specify the present invention below in conjunction with accompanying drawing and embodiment.

Description of drawings

Shown in Figure 1 for illustrating according to manufacturing crystalline schematic representation of apparatus of the present invention.

Shown in Figure 2 is that middle mind-set is all around to tilt for illustrating according to the preferred of manufacturing crystalline device of the present invention with the crystal selector position

Curved surface is connected to several kinds of crucible bottom structural representations (containing evagination, indent, terrace with edge, multistage terrace with edge, round platform) of sidewall.

Shown in Figure 3 for illustrating synoptic diagram according to the liquation mechanical stirring device of manufacturing crystalline device of the present invention.

Shown in Figure 4 for illustrating synoptic diagram according to the liquation magnetic field whipping appts of manufacturing crystalline device of the present invention.

Schematic representation of apparatus of the present invention is diagrammatic cross-section, and the relative size that each position showed among the figure according to clearly showing and making things convenient for the needs of drawing to adjust, is not represented actual ratio or size.

Description of reference numerals

1, crucible; 11, crucible crystal selector position; 111, crystal selector position initial section;

112, the brilliant section of crystal selector position choosing; 113, crystal selector position monocrystalline section; 12, crucible diapire intermediate location;

2, crucible bracing or strutting arrangement;

3, heating unit; 32, near heating unit or the refrigerating unit the crystal selector position

4, small-particle raw material;

5, raw material solid or melt;

6, mechanical stirring device; 61, stir the position;

71,72,73: stir magnetic pole;

8, the furnace shell of vertical direction coagulation system

Embodiment

Fig. 1 shows the silicon crystal manufacturing installation of the silicon crystal growing process that adopts the VGF method; Be clear demonstration characteristic of the present invention; Only provide the synoptic diagram of the crucible 1, crucible bracing or strutting arrangement 2 and the heating unit 3 that include crystal selector among the figure, and only show relative position between each position, do not represent true ratio.According to Fig. 1, crucible 1 is formed by quartz crucible, and its diapire middle part is provided with spiral crystal selector 11, and crystal selector is followed successively by initial section 111, brilliant section of choosing (spirochete) 112 and monocrystalline section 113 from top to bottom.The crystal selector position is connected to sidewall with arc diapire 12 recessed in crucible to the sidewall expansion at the place suitable for reading of monocrystalline section, and 12 is the gradually changeable transitional region of diapire.The sidewall of crucible is upright, surrounds the crucible cavity with diapire, holds silicon raw material 5.For making the cavity at the less crystal selector position of silicon raw material filling size, note adopting the less silicon material 4 of size to insert this position earlier.

Crucible bracing or strutting arrangement 2 has the bearing surface of fitting with the curved surface shaped part surface 12 of crucible diapire and can hold the cavity at crystal selector position at least.Heating unit includes the Heater group 31 that places around the crucible, optional heating unit or refrigerating unit 32, and wherein, heating unit or refrigerating unit 32 are arranged near the crucible crystal selector position.The also optional well heater that is arranged at the crucible over top that includes of heating unit.

The embodiment of the present invention method starts well heater earlier and makes the silicon material fusing in the crucible, then; The output of control heater makes and forms thermograde longitudinally in the crucible, wherein; The initial section temperature at crystal selector position that is positioned at the crucible lowest part is minimum but be higher than the silicon fusing point, optionally keeps for some time to guarantee fusing fully, when keeping described thermograde longitudinally then; From crucible bottom cooling silicon melt, make silicon melt begin to solidify from bottom to up, through heating and the heat radiation of carefully controlling crucible from the crystal selector initial section; Keep the freezing interface to be level or near horizontal state the time, the freezing interface is slowly moved up, silicon liquid all solidifies in crucible; The silicon that solidifies in the cooling crucible is chosen wantonly in the refrigerative process and is applied annealing steps, takes out chilled silicon ingot at last; Promptly obtain crystal silicon idiosome (crystal ingot) monocrystalline or nearly monocrystalline, the convexity and the crystal selector position of excision flaw-piece, cutting-out idiosome bottom, the crystal silicon idiosome main body of acquisition promptly can be used for the silicon wafer of manufacture batteries sheet.

Adopt different crucible shape and size, can obtain the monocrystalline or the polysilicon idiosome main body of different shapes and size.The main body of described idiosome, be meant that crucible wall surrounds, be positioned at sidewall bottom crystal idiosome part above water, the crucible of this part also is referred to as the main part of crucible.The shape and size of the crystal idiosome main body that the present invention makes depend on the shape and size of crucible main body fully, and almost the crucible manufacturing possibly have no restriction down, still, preferably have the geometrical shape of rule.For example, adopt the cylindrical or quadrate crucible of main part, can obtain cylindrical or the quadrate ingot.Distinguishingly, adopting the main part xsect is sexangle or octagonal crucible, and can obtain main body is the silicon crystal idiosome of hexagonal prism or eight prisms.The embodiment that some are concrete; Comprise the crucible that adopts suitable dimension and shape respectively; Obtain the about 20cm of diameter, 25cm, 31cm, 15 inches, 18 inches, 20 inches cylinder crystal idiosome; And height is about 5.1cm, 11cm, 15cm, 20cm, 25cm, 30cm, 35cm, 40cm, 50cm, the hexagon prism of the square crystal ingot of the about 5～100*5 of the length of side～100cm and the various height of the about 5～100cm of the length of side or eight prism crystal ingots.Obviously, through the shape and size of adjustment crucible, almost can design the crystal idiosome of different shapes and size without restriction.According to crystalline density; Can be from the size design of crucible; Construct the almost crystal idiosome main body of any weight; From about 1kg to about 2000kg, even about 10 tons, the size that only is limited to device of the present invention itself and crucible with need with crucible supporting solidify the time to the accurate controllability of thermal field.

Apparatus and method of the present invention can obtain the monocrystalline idiosome of large-size, far exceed the size of the crystal bar of common CZ method, the acquisition of FZ method.From such crystal idiosome can cut the single-chip of large size particular crystal orientation, for example about 30cm of diameter or 35cm or 40cm and the above about 35*35cm of wafer, area ², or about 40*40cm ², or about 50*50cm ², about 60*50cm ²Square or rectangular bimorph, the manufacture craft of pressing the photovoltaic cell sheet can be processed corresponding large size photovoltaic cell sheet with these wafers, adopts the wafer fabrication photovoltaic cell of method of the present invention, has higher make efficiency.

The embodiment at the crucible crystal selector position that the part that the present invention can select is dissimilar is referring to document " directional solidification technique is produced the thinking of superalloy single crystal casting " (the 15th the 2nd phase of volume of Hunan Institute Of Engineering's journal, in June, 2005).Wherein, use the crucible that contains spiral crystal selector position, can obtain the silicon single crystal idiosome of crystal orientation, use the crucible that contains apsacline or dimensional constraints type crystal selector position, can obtain the macromeritic polysilicon idiosome of column for < 001>or < 100 >; Use contains the crucible at cucurbit serial type crystal selector position, can obtain the macromeritic polysilicon idiosome of column under the certain situation, can obtain the monocrystalline idiosome under other situation.Different crystal selector kinds can make up or be used in combination, or do suitable distortion, obtain better effect sometimes.For example, an embodiment is that the crucible at the cucurbit serial type crystal selector position that employing is tilted obtains the silicon single crystal idiosome more.

Some embodiment are following;

Employing contains the crucible at spiral crystal selector position, and the initial section at its spiral crystal selector position (referring to cavity, down together) is cylindrical, and diameter is got any number between about 0.1～10cm, highly gets any number between about 0.5～5cm; The brilliant section of choosing (spiral section) is highly got any number between about 1～20cm, and the screwed pipe internal diameter is got any number between about 0.1～10cm, and the spirochete external diameter is got any number between about 0.5～30cm, and the spiral number of turns is got any number between about 0.5～3 circle; The monocrystalline section is cylindrical, and diameter is got any number between about 0.1～10cm.Obviously,, between each size of the three-stage structure at spiral crystal selector position correspondence should be arranged for obtaining the brilliant effect of good choosing, like the diameter of the about 1cm of initial section, the spiral section screwed pipe internal diameter of corresponding about 0.5～2cm and the monocrystalline section internal diameter of about 1～3cm.An embodiment is that the initial section at crystal selector position is cylindrical, high about 5cm, the about 3.5cm of internal diameter; The high about 8cm of spiral section, the about 1.2cm of screwed pipe internal diameter, about 1 circle of the spiral number of turns, the about 3.5cm of spirochete external diameter.Another embodiment is that the initial section at crystal selector position is cylindrical, high about 4cm, the about 3cm of internal diameter; The high about 5cm of spiral section, the about 12cm of screwed pipe internal diameter, about 0.5 circle of the spiral number of turns, the about 3cm of spirochete external diameter.Higher crystal selector position or the size of its each section when meaning that reducing the thermograde control accuracy requires, have prolonged growth cycle.

Similarly, contain the size at other types crystal selector position, can be with reference to above-mentioned data area.For example, a crucible that contains cucurbit serial type crystal selector position, the desirable about 2.8cm of height of the portion of expanding of its cucurbit string; The about 2.6cm of maximum transverse diameter, the about 1.3cm of narrow neck internal diameter, the high about 10cm of cucurbit string; Comprise 2 and expand portion, the high about 2cm of the columniform initial section of bottom, the about 2.7cm of internal diameter.Another contains among the embodiment of crucible at cucurbit serial type crystal selector position, is that about 30 degree angles are arranged in above-mentioned cucurbit string structure position, and this frame mode can improve and select brilliant effect, and saves the space.

Also can choose far beyond larger sized crystal selector position in the foregoing description.Bigger crystal selector spot size, its crucible are made easily, the temperature control of heating unit is easy, but it is many to expend raw material.

The crucible of another embodiment of the device of manufacturing silicon of the present invention or Si Ge crystal, it contains 2 dimensional constraints type crystal selector positions.During crystallization, crystal generates and growth at 2 crystal selector positions respectively.

When crucible comprised more than one crystal selector position, the polycrystalline crystal arrangement of acquisition was more neat, and defective is few, and grain-size is big, but crucible is made complicacy.Method of the present invention, the preferred mode that comprises a crystal selector position of using.

Because the monocrystalline section position (or epimere part of crystal selector) of the crystal selector of crucible of the present invention is vertical arrangement; It will be connected to the sidewall equally longitudinally that is positioned at around its outside, and crucible must contain monocrystalline section position (or epimere part of crystal selector) from crystal selector to the turnover of horizontal direction or the part diapire of deviation, and the contriver finds; If the diapire of this part turnover or deviation; The angle of its turnover or deviation is bigger, and is perhaps more unexpected, make the monocrystalline section position of diapire and the angle that between the connecting portion of sidewall, outside crucible, forms near the right angle; Then generate stray crystal near the crucible the right angle easily; Or cause more lattice defect, or bigger internal stress, the crystalline quality reduced.Simultaneously; Because the maximum transverse size, the particularly maximum transverse size of crystal selector epimere at crystal selector position are compared with the crucible maximum transverse size; Differ greatly; And if crystal selector position and its with the crystal growing process between the upper part in, significantly increasing suddenly of lateral dimension taken place, also can have influence on the crystalline growth quality.Therefore, among the present invention, make other positions and the continuity of sidewall from crystal selector epimere position to diapire, the dimensional change and the inclination angle that keep mild as far as possible change.For this reason; Preferred embodiment be; Make of the continuity of crystal selector monocrystalline section (or epimere of the crystal selector) position of crucible, be stretched over sidewall, promptly to the sidewall bottom, include the gradually changeable intermediate location from crystal selector is suitable for reading with gradual change or mild turnover or the mode of deviation to sidewall.For this reason, the present invention proposes following concrete scheme.

Shown in Figure 2 for according to the device of manufacturing silicon of the present invention or Si Ge crystal be several kinds of crucible bottom structural representations (containing evagination, indent, terrace with edge, multistage terrace with edge, round platform) that are connected to all the other positions 14 of sidewall bottom or diapire around the middle mind-set with the intermediate location 12 of the curved surface that tilts preferably with the crystal selector position, the crystal selector position only illustrates the monocrystalline section part 113 on its top among the figure.

Fig. 2-the 1st contains the synoptic diagram of intermediate location embodiment of the crucible diapire of spirogyrate.

Fig. 2-the 2nd contains the synoptic diagram of intermediate location embodiment of the crucible diapire of concave shaped (tubaeform).

Fig. 2-the 3rd contains the synoptic diagram of intermediate location embodiment of the crucible diapire of terrace with edge or truncated cone-shaped.

Fig. 2-the 4th contains the synoptic diagram of intermediate location embodiment of the crucible diapire of second order terrace with edge shape.

The connecting zone that the intermediate location of the above-mentioned inclination of crystal selector monocrystalline section 113 (epimere) and diapire is 12, preferably close with described intermediate location structure, form mild or level and smooth dividing a word with a hyphen at the end of a line with the mode of gradual change size.Especially; The crucible diapire main part to the sidewall continuity around the crystal selector position presents convex shape; When a center of curvature that is positioned within the crucible cavity is promptly arranged; Described zone of transition preferably is rendered as inwardly recessed shape (as bell-mouthed shape), a shape that is positioned at the outside center of curvature of crucible cavity is promptly arranged, to guarantee the good quality of crystal growth at this transitional region place of crucible.

Said structure design of the present invention can reduce the temperature contrast that is positioned at the turnover angle in the crucible cavity, reduces crystal stress, improves the crystalline quality, also reduces the manufacture difficulty and the cracked risk that reduces crucible of crucible simultaneously.

A kind of embodiment of manufacturing silicon of the present invention or Si Ge crystal is to use seed crystal to place in the initial section at crystal selector position or the seed crystal section that optional initial section below is provided with; Method is; When in fusion crucible, being positioned at the raw material above the seed crystal, the part seed crystal does not melt to keep at least to control suitable longitudinal temperature gradient and temperature, keeps solidifying-melt interface of an almost horizontal at the position of seed crystal; Then; Adjustment heating power input or cold fuse-element, making this solidifies-and melt interface moves on gradually, up to whole melt solidifyings.As the shape and size of optional seed crystal section, can select identical with the crystal selector initial section or close.For the crucible of quartz material, a kind of embodiment is, can make the crystal selector position of bottom end opening earlier, put into seed crystal from opening part after, with the method for sintering or welding, the sealing opening.Perhaps make open upper end with the isolating initial section of other parts of crystal selector position, lay seed crystal after, with this initial section welding or sintering that contains seed crystal on other parts at crystal selector position.

Above-mentioned seed crystal of the present invention; And hold the cavity geometry in initial section or the seed crystal section of seed crystal, can choose wantonly with one of next group shape: cylindrical, prismatic, cuboid, long strip shape, elongated truncated cone-shaped, elongated terrace with edge property, taper shape, pyramid, long thin slice shape, have one and vertically go up the random shape of the size of length.The three-dimensional minimum and maximum size of the cavity in the initial section of above-mentioned seed crystal of the present invention and seed crystal or the seed crystal section can be chosen wantonly from organizing data area with next: about 1～50cm, about 0.1～5cm.For example, take and be about 10cm, wide about 1cm, the rectangular single crystal of thick about 0.5cm be as seed crystal, inserts to have similar shape but the initial section of more bigger inner chamber body.

In apparatus and method of the present invention, the embodiment of above-mentioned employing seed crystal can obtain the crystal consistent with the seed crystal crystal orientation, thereby can obtain the crystal of optional particular crystal orientation.

Each position of the crucible of device of the present invention comprises sidewall, diapire crystal selector position, reaches crystal selector position diapire all around, and can adopt the material different manufacturing, but preferably adopt the identical materials manufacturing, as adopt quartzy material, or the quartz-ceramics material.The manufactured materials of crucible of the present invention; When being used for cast silicon and Si Ge crystal; Can select graphite, aluminum oxide, silicon nitride, silicon nitride combined silicon carbide, quartz, quartz-ceramics, zirconium white, Natural manganese dioxide, quicklime or the like, the material of preferred quartz, quartz-ceramics and silicon nitride comprising.Cast other crystal, the crucible material of being selected for use needs and the material of casting adapts, like high temperature tolerance, reactionlessness, do not dissolve each other or the like.In general, its material of crucible of the present invention does not receive the restriction of invention itself, and all can do the material of crucible, all is suitable for.The example of the material of high-temperature crucibles more of the present invention; Comprise: refractory metal is platinum, nonmetal for example boron, alloy tungsten, steel refractory materials clay, oxide compound chromic oxide, the oxide ceramics spinel for example for example for example of carbon steel, chromium steel, mixing element for example for example for example; Nitride is SP 1, carbide titanium carbide, rare earth oxide yttrium oxide or the like for example for example for example; Last listed various materials or its compsn of this paper can be made crucible of the present invention.

Fig. 3 and shown in Figure 4 be synoptic diagram according to the liquation whipping appts of the device of manufacturing silicon of the present invention or Si Ge crystal.Only illustrate the top of crucible and melt among the figure.Wherein, a kind of instance of embodiment is as shown in Figure 3, and mechanical stirring device 6 is set, and it includes the stirring position 61 that can insert in the liquation, when solidifying, starts this whipping appts, stirs liquation 5.Another kind of embodiment is that the time-varying magnetic field whipping appts is set outside crucible, and wherein, an embodiment is shown in Fig. 4-1, and the magnetic pole 71 of magnetic field whipping appts is arranged on the crucible top; Another embodiment is shown in Fig. 4-2, and the magnetic pole 72 of magnetic field whipping appts is arranged on around the crucible wall; Another embodiment is shown in Fig. 4-3, and the magnetic pole 73 of magnetic field whipping appts is arranged on most external, furnace shell 8 outsides of apparatus of the present invention.

In one embodiment of the invention, molten silicon is provided in the silicon solidification crucible from a container that is arranged on outside the described silicon solidification crucible.For example; An embodiment includes a plumbago crucible, and plumbago crucible is outside equipped with heating unit, and the silicon material is heated therein and is fused into silicon liquid; Be introduced into (for example topple over and be positioned at the elevated plumbago crucible) then to the silicon solidification crucible, the molten silicon of part has been contained or do not contained to the latter.Then the molten silicon of control is pressed aforesaid predetermined mode solidification and crystallization in crucible.

As an embodiment; Get and have crucible spiral crystal selector position, that have the centre portions that is measured as the horizontal square-section of 50cm*50cm; Place a VGF device of the present invention; Charging feedstock silicon and doping agent are by the crystal ingot of method acquisition of the present invention, for having the silicon single crystal ingot of the centre portions that is measured as the horizontal square-section of 50cm*50cm.To the visually inspect on the surface of ingot, can obviously find out monocrystal silicon structure.Corrodibility preparation etching silicon with delineating crystal boundary has also further confirmed in material, to lack crystal boundary.Its body doping average out to 1.3ohm.cm, the sensitive cell of making thus has 16.7% photoelectric efficiency.

As another embodiment; Get have spiral crystal selector position, to have the centre portions, the crystal selector position that are measured as the horizontal square-section of 60cm*60cm above height suitable for reading be the quartz ceramic crucible of 45cm; Crucible inwall coating silicon nitride coating; Place a vertical direction solidified cast device with graphite heater of the present invention; Pack into the raw silicon and the P type doping agent of sufficient quantity, for example optional doping agent from boron, gallium, aluminium, and pack into and make the gained crystal ingot reach average germanic 0.5*10 through metering ¹⁶～1*10 ²⁰Cm ^-3The germanium grain, then by the inventive method, through heat fused; Insulation is when setting up the gradient temperature distribution in the crucible and keeping gradient temperature to distribute; Begin the crucible bottom of lowering the temperature from the crystal selector position; Silicon melt is upwards solidified gradually, slowly cool to room temperature after solidifying completion, take out the crystal ingot in the crucible.The crystal ingot that obtains is for having the silicon single crystal ingot of the centre portions that is measured as the horizontal square-section of 60cm*60cm.To the visually inspect on the surface of ingot, can obviously find out monocrystal silicon structure.Corrodibility preparation etching silicon with delineating crystal boundary has also further confirmed in material, to lack crystal boundary.The thickness of adjustment crucible coating layer, atmosphere, air pressure and the gas flow rate of crucible during the processing links such as adjustment heat, melts, solidified, cooling, and the treatment time of above-mentioned each link of change can obtain nitrogen, carbon, crystal ingot that oxygen level is different.

Wherein, an again embodiment consistent with present embodiment does fast at the crystal selector position and to solidify, and can obtain polycrystal, analysis be since too fast solidifying cause choosing brilliant not exclusively due to.And use has the embodiment of the quartz crucible at apsacline or cucurbit serial type crystal selector position, and mostly the crystal ingot of acquisition is polycrystal.

In the consistent embodiment of the embodiment of other and crystal silicon of the present invention growth, the mixing of nitrogen, carbon and oxygen is the mode of the carbon that adopted adding silicon in the silicon raw material, nitrogen, oxide compound, for example silit, silicon nitride, silicon-dioxide.

The wafer of the suitable thickness of being processed by the silicon consistent with embodiment of the present invention can be n type or p type, and can be used for semiconductor components and devices, for example sensitive cell.For example, wafer can be about 50 micron thick to about 500 micron thick.In addition, be used for photronic wafer and preferably have diffusion length (Lp) greater than wafer thickness (t).For example, Lp is suitably at least 0.5 with the ratio of t.For example, it can be at least about 1.1 or at least about 2.Diffusion length is meant the mean distance that minority carrier (the for example electronics in the p type material) can spread before compound with majority carrier (hole in the p type material).Lp is associated with minority carrier lifetime tau through relational expression Lp=(D τ) ^ (1/2), and wherein D is a diffusion constant.The width of wafer can be about 100mm to about 600mm.Preferably, at least one of wafer is of a size of at least about 51mm (2 inches).For example, by the wafer of silicon preparation of the present invention, and the sensitive cell that is therefore prepared by the present invention can have about 25 to about 2500 square centimeters surface-area.The front surface of wafer preferably textured (process matte, or be referred to as decorative pattern crosses).For example, can utilize suitably decorative pattern wafer of chemical milling, plasma etching or laser or mechanical scribing.

Thereby, as an embodiment, form at least one wafer through the solid entity that cuts silicon ingot of the present invention; Choose wantonly and on wafer surface, implement cleaning step; Choose wantonly and on wafer surface, implement the decorative pattern step; Optional to wafer enforcement heat treatment step; Form p-n junction, for example pass through surface doping; The optional ARC that deposits from the teeth outwards; Optional formation is selected from one deck at least of back surface field and passivation layer, for example through the aluminum sinter step; And on wafer, form conductive contact, and thus, can use the wafer of producing by according to the crystal silicon ingot of embodiment of the present invention, produce sensitive cell.Passivation layer is the layer that has the interface with the naked wafer surface of the dangling bonds that maintains surface atom.The example of the passivation layer on the silicon comprises silicon nitride, silicon-dioxide and amorphous silicon.This layer is also thinner, perhaps transparent to only than 1 micron usually, perhaps as anti-reflecting layer.

In for example using photronic typical case of p type silicon wafers and general method, make wafer under high temperature, be exposed to suitable n type doping agent in a side, thereby in the front side of wafer or receive flash ranging to form emitter layer and p-n junction.For further improving photoabsorption, can apply optional ARC in the front portion of wafer usually, for example silicon nitride provides surface and/or the passivation of body phase simultaneously sometimes.

Be exposed to the current potential that luminous energy produces in order to utilize through p-n junction, sensitive cell provides the preceding electrical contact of conduction usually at the front surface of wafer, and the back electrical contact of conduction is provided on the back surface of wafer.Electrical contact is processed by the metal of conduction usually.

By adulterated semiconductor crystal of the present invention; For example silicon, SiGe, gallium arsenide; The wafer of processing that comprises at least one group of p-n junction and conductive contact can be used as semiconductor element, for example diode element, triode, thyristor element, sensitive cell sheet.For example when the p-n junction that need include more than a group, the wafer of processing can have the thickness that needs.

Therefore; The sensitive cell consistent with above-mentioned embodiment can comprise by not containing or being substantially free of the continuous silicon single crystal of radial distribution defective or advancing the wafer that silicon single crystal ground entity forms; This entity can be as indicated above; For example, have at least about at least 2 sizes of 25cm with at least about the 3rd size of 20cm; P-n junction in the wafer; The ARC of choosing wantonly on the wafer surface; Preferably has the one deck at least that is selected from back surface field and passivation layer; And the conductive contact on the wafer, wherein this entity can not contain or be substantially free of swirl defect and not contain or be substantially free of the OFS defective.

In a Test Example of the embodiment of carbon containing oxygen nitrogen germanium of the present invention unanimity, the single crystal rod of acquisition has the 75*75cm cross-sectional dimension, the high 35cm of crystal ingot behind the excision crystal selector position; Its body doping average out to 1.5ohm.cm; The series of wafers of ingot cutting acquisition has first and second sizes at least about 30cm, at the most first and second sizes of about 70cm thus; The sensitive cell of its manufacturing has 16.3～17.7% photoelectric efficiency.

Those skilled in the art is obvious, under the situation that does not depart from scope of the present invention or design, can make various modifications and distortion to the structure and the method that are disclosed.

For example, the process relevant with forming silicon single crystal and the method that are disclosed also are applicable to polysilicon or its combination that forms nearly silicon single crystal, big crystal grain particular crystal orientation.

More than each embodiment and embodiment, can be used for adopting crystal growth technique equally based on the forging type of heat-exchanging methods such as VB method, VBS method.

In addition; Though the invention describes the casting of silicon and SiGe; But under the situation that does not depart from scope of the present invention and design; Also can cast other semiconductor materials and metal and nonmetal crystal material, comprise any its state behind the melt solidifying, its structure is a crystal or same or similar with quasicrystal or smectic body.As an example; The material that the present invention cast comprise in the periodic table of elements from No. 3 to the ununoctium at normal temperatures or be in solid-state or liquid under the warming and pressurizing and any element of liquid state is arranged when temperature is higher; And the compound of the single component that forms of these element chemical combination, comprise metal, nonmetal, semiconductor material, pottery, comprise carbon family, nitrogen family, chalcogen, compound haloid; Comprise metallic compound; Comprise the compound of semiconductor element, comprise intermetallic compound, and the arbitrary composition of above-mentioned these simple substance and compound.For example; The inventor has imagined the other materials consistent with embodiment of the present invention, for example germanium, gallium arsenide, gan, aluminum oxide, zinc oxide, zinc sulphide, InGaAsP, indium antimonide, yttrium ba oxide, lanthanide oxide and other semi-conductors, oxide compound and with the casting of the intermetallic compound of liquid phase.Consider specification sheets and put into practice the invention that discloses among this paper that those skilled in the art can other embodiments obviously of the present invention.

As the compound of method and apparatus casting of the present invention or the object lesson of alloy material or intermetallic compound or stupalith, the compsn of one or more that include, but is not limited in following material, choose wantonly: AlSb, Al2S3, Al2Se3, Al2Te3, Sb2O3, Sb2S3, Sb2Se3, Sb2Te3, As2S3, As2Se3, As2Te3, Bi2Se3, Bi2Te3, Bi2O3, Bi2S3, CdAs2, Cd3As2, CdSb, CdSe, CdS, CdTe, Cu2S, CuGaSe2, CuGaTe2, CuInS2, CuInSe2, CuInTe2, CuTlSe2, CuTlTe2, GaAs, GaSb, Ga2O3, GaS, Ga2S3, GaSe, Ga2Se3, GaTe, GeS, GeS2, GeSe, GeSe2, GeTe, HgS, HgSe, HgTe, InBi, InAs, InSb, In2O3, InP, InSe, In2Se3, In2S3, InTeO, InSeO, InTe, In2Te3, PbO, PbS, PbSe, PbTe, AlTe, Mg2Si, Mg3Bi2, MgGe, MgSn, Mg2Pb, SnS, SnSe, SnSe2, NiS, SnTe, Ag2S, Ag2Se, Ag2Te, AgGaSe2, AgGaTe2, AgInS2, AgInSe2, AgInTe2, AgTlSe2, AgTlTe2, TeO2, SnO2, SnO, SnSe, SnSe2, SnTe, TlSe, Tl2S, ZnAs2, Zn3As2, ZnSb, Zn3P2, ZnS, ZnSe, WSe2, ZnTe, SiO2, TiO2, Ti3O5, Ti2O3, Al2O3, MgO, CaO, Cu2O, Nd2O3, Gd2O3, Y2O3, CaF2, LaF3, CeF2, Ce6K7F31, PrF3, NdF3, GdF3, DyF3, YF3, SeN, YN, La2S3, CuInSe2, CuInGeSe2, Cu (In _xGa _(1-x)) Se2, Cu2ZnSnS4, Ti3Al, TiAl, Ni3Al, FeAl, Fe3Al, MoFe2, WFe2, NbFe2, TiFe2, MgCu2, MgNi2, Nd-Fe-B alloys, yttrium barium copper oxide, Al2O3-YAG, Al2O3-GAP, Al2O3-ZrO2, Al2O3-EAG, Al2O3-EAG-ZrO2, Al2O3-(RE) AlO3, ZrO2-CaO, CaF2-MgO, MgO-MgAl2O4, NiO-CaO, NiO-Y2O3.

Claims (15)

1. one kind is used the vertical direction freezing method to make the crystalline method; Comprise providing crucible that wherein the diapire of the crucible crystal manufacturing installation that includes the crystal selector position that is positioned at the crucible bottommost and the vertical direction freezing method that includes crucible heating unit, crucible bracing or strutting arrangement is provided is to hold described crucible to hold crystal raw material with axial sidewall basically; Starting heating unit and control should heat; Formation from crucible bottom to top temperature increased temperature gradient distribution thermal field gradually, the raw material in the fusion crucible, the melt that cools off then in the crucible makes it begin upwards to solidify as direction from bottom, crystal selector position; Obtain the crystal entity; Characteristic of the present invention is, between the suitable for reading and crucible wall bottom at the crystal selector position of diapire, includes the gradually changeable intermediate location that the horizontal section of its cavity that surrounds enlarges gradually.

2. according to the method for claim 1; It is characterized in that; The gradually changeable intermediate location of described crucible diapire; Formation is the center with a crystal selector position, comprises cambered outwards bowl-type to take from, inwardly any in one group of structure of spill (tubaeform), single-order or multistage truncated cone-shaped or terrace with edge shape upwards tilts continuity and be connected to bottom the sidewall to sidewall direction gradually.

3. according to the method for claim 1～2, wherein, has ratio between the cavity of described crucible by the place suitable for reading, crystal selector position of cavity that axial sidewall surrounded and diapire greater than 60 horizontal section area.

4. one kind is used the vertical direction freezing method to make the crystalline device; It comprises crucible and the crucible bracing or strutting arrangement that has axial basically sidewall, connects the diapire of sidewall, and contains the heating unit of at least one group of well heater; Wherein the diapire of crucible includes the crystal selector position that is positioned at the crucible bottommost; The invention is characterized in, between the suitable for reading and crucible wall bottom at the crystal selector position of diapire, include the gradually changeable intermediate location that the horizontal section of its cavity that surrounds enlarges gradually.

5. according to the device of claim 4; It is characterized in that; Seed crystal holds the ratio of position smaller cross-sectional area area suitable for reading and the bigger cross-sectional area of crucible cavity less than 1/60; The intermediate location of the gradually changeable of described crucible diapire; Formation is the center with a crystal selector position, with take from next group in the shape any one, upwards tilt continuity and be connected to the base structure at all the other positions of sidewall bottom or diapire gradually to sidewall direction: cambered outwards bowl-type, inside spill (tubaeform), single-order or multistage truncated cone-shaped or terrace with edge shape.

6. according to the device of claim 4～5, it is characterized in that, near the described crystal selector position, be provided with the independent temperature setting device of one of optional self-heating apparatus and refrigerating unit at least.

7. according to the device of claim 4～5, it is characterized in that, also be provided with optional melt whipping appts from one of mechanical stirring device and electromagnetic mixing apparatus.

8. one kind is used vertical direction freezing method casting crystalline crucible; It comprises the crucible that has axial basically sidewall, connects the diapire of sidewall; The diapire of crucible includes the crystal selector position that is positioned at the crucible bottommost; Wherein the cavity horizontal section area at place suitable for reading, crystal selector position and the ratio of the horizontal section area of passing sidewall are less than 1/60; Characteristic of the present invention is, between the suitable for reading and crucible wall bottom at the crystal selector position of crucible diapire, includes the gradually changeable intermediate location that the horizontal section of its cavity that surrounds enlarges gradually.

9. according to Claim 8 crucible; The gradually changeable intermediate location of described crucible diapire; Formation is the center with a crystal selector position, with take from next group in the shape any one, upwards tilt continuity and be connected to the base structure at all the other positions of sidewall bottom or diapire gradually to sidewall direction: cambered outwards bowl-type, inside spill (tubaeform), single-order or multistage truncated cone-shaped or terrace with edge shape.

10. according to 8～9 crucible, the staple of its material combines a kind of in silicon nitride, silicon nitride, quartz, quartz-ceramics, aluminum oxide, zirconium white, quicklime, the Natural manganese dioxide for optional from graphite, silit, silit.

11. direction solidified cast monocrystalline or the continuous entity of polycrystalline; Include as the crystal selector position and the crystalline body position of solidifying initial position; It is characterized in that; With the area that solidifies the vertical crosscut of direction cross section at described body section and the ratio that solidifies upper end, initial position greater than 60, solidify between initial position and the crystalline body position described, include the gradually changeable intermediate location that it enlarges with the area that solidifies the vertical crosscut of direction cross section gradually.

12. according to 11, described crystal is the semiconductor crystal that contains doping agent.

13. the method for manufacture of semiconductor wafer or device; Comprise the adulterated semiconductor crystal entity of producing according to the method for claim 1～5 is provided, by this crystal formation wafer, on this wafer; Optional at least one p-n junction that forms; The optional conductive contact (or line/band) that forms is chosen this wafer of encapsulation wantonly, chooses wantonly additional device is connected on this wafer.

14. sensitive cell sheet or photronic method of manufacture comprise:

Adulterated semiconductor crystal entity according to claim 1～5 is provided; At least form a wafer by this entity;

Optional to wafer enforcement heat treatment step; Choose wantonly in wafer surface and implement cleaning step; Choose wantonly and on this surface, implement the making herbs into wool step;

Form p-n junction; Choose wantonly on this surface and deposit ARC; Optional formation is selected from one deck at least of back surface field and passivation layer;

And on wafer, form conductive contact (line, band); Optional with wafer package and draw conductor wire.

15. according to claim 11 or 12 described crystal, it is used to make optional purposes from one of p type, n type, the wafer that contains p-n junction or semiconducter device.

Images