A kind of ingot casting thermal field of the pure accurate monocrystalline of growing
Technical field
The present invention relates to a kind of ingot casting thermal field of the pure accurate monocrystalline of growing.
Background technology
Polycrystalline silicon ingot or purifying furnace is a kind of visual plant of the photovoltaic material of growing, and in production, the polysilicon that reaches certain purity requirement is proceeded in stove, according to processing requirement heat fused, directional long crystal, thermal treatment, cooling coming out of the stove.Build the silicon crystal needed parts of growing and be referred to as thermal field, single for unmelted polycrystalline silicon provides a large amount of heat energy, in long brilliant process, provide again the polysilicon crystal of rational temperature gradient field to obtain meeting the requirements.
Accurate monocrystalline, also referred to as ingot casting monocrystalline, is to utilize directional solidification method growth to have the crystal of single crystal-like silicon characteristic, and its growing principle is the traditional method of utilizing seed crystal revulsion growing single-crystal.Its main process is: first in quartz ceramic crucible bottom, place silicon single crystal as seed crystal; and then load silicon raw material thereon; in the fusion stage, by cooling quartz ceramic crucible bottom, reduce the temperature of seed crystal bottom surface; protection seed crystal bottom is not completely melted; after seed crystal partial melting, start long brilliant; in long brilliant process; design defect due to traditional thermal field; the loss that type of thermal communication is crossed crucible wall causes the generation of the nucleus in crucible inner wall surface and grows up; and the growth making progress along with crystal; crystal grain constantly extends to crystals, and area constantly increases.Therefore when using traditional polycrystalline ingot furnace to grow accurate monocrystalline crystal, near 16 crystal bars of crucible wall, normally comprise the compound silicon chip of the common polycrystalline of part (<111> crystal orientation is main) and the accurate monocrystalline of part (<100> crystal orientation) structure.Difference because of crystal orientation, when employing can be brought into play the alkali leather producing process making cell piece of quasi-monocrystalline silicon advantage, because polycrystalline part be take <111> crystal orientation as main crystal grain, can not prepare pyramid suede structure, make the aberration of silicon chip two portions crystalline structure obvious, not only affect the outward appearance of cell piece, also affect the efficiency of conversion of cell piece.
Patent CN102140673 has proposed the polycrystalline silicon ingot furnace heating device that a kind of top side well heater is separately controlled, to improving the crystal ingot later stage, the crystalizing interface of position, germ nucleus plays good effect, but the interface near crucible wall is not significantly improved, and the small grains that sidewall of crucible is looked unfamiliar still can inwardly be grown.And in long brilliant first half, crystal is in below side well heater, because crucible wall surrounding is away from side well heater, heat radiation to surrounding also makes a large amount of small grains generate with crucible wall and to crystal ingot growth inside, destroy the crystalline structure of single crystal growing, be difficult to realize all 25 spillikins 100% for complete accurate single crystal structure.
Patent CN202054920 has proposed a kind of device for growing single-crystal silicon by directional solidification method, its implementation is at crucible bottom arranged outside heat insulation device, the heat radiation that stops crucible to be avoided, for the formation that suppresses crucible wall place nucleus, have certain effect, but because mode of operation is passive insulation, can not suppress formation and the growth of new nucleus on the front crucible wall of crystalizing interface completely, and the transition insulation to crucible wall, center crystalizing interface, by epirelief, is unfavorable for the raising of crystal mass.
Summary of the invention
The technical problem to be solved in the present invention is: overcome the deficiencies in the prior art, a kind of ingot casting thermal field of the pure accurate monocrystalline of growing is provided, the ratio of the pure accurate monocrystalline crystal bar of growing is higher.
The technical solution adopted for the present invention to solve the technical problems is: a kind of ingot casting thermal field of the pure accurate monocrystalline of growing, there is upper furnace body, lower furnace body, described upper furnace body, in the cavity that lower furnace body forms, be provided with quartz ceramic crucible, described quartz ceramic crucible outer exterior wall is provided with sidepiece primary heater, described quartz ceramic crucible top is provided with top primary heater, between described quartz ceramic crucible outer wall and sidepiece primary heater, be provided with portable secondary heater, described portable secondary heater is connected with secondary heater electrode, described secondary heater electrode is connected with secondary heater electrode running gear through upper furnace body, described secondary heater electrode running gear is arranged on upper furnace body, described secondary heater electrode running gear drives on portable secondary heater by secondary heater electrode, lower movement, the velocity curve of the described bottom-up movement of portable secondary heater is consistent with the brilliant velocity curve of length of seed of single crystal silicon in quartz ceramic crucible.
Further, described portable secondary heater is annular, and described portable secondary heater was around the outer wall wall of quartz ceramic crucible one week.
Further, described secondary heater electrode is three electrode bars that distribute along even circumferential, and three electrode bars are all connected with annular portable secondary heater.
Further, described quartz ceramic crucible is placed in plumbago crucible, described plumbago crucible bottom is provided with graphite and helps grumeleuse, described graphite helps grumeleuse to be supported by pillar stiffener, in described quartz ceramic crucible, be added with silicon solution, described plumbago crucible is positioned at the incubation cavity sidewall of bottom opening, described sidepiece primary heater is between incubation cavity sidewall and plumbago crucible outer wall, described portable secondary heater is between plumbago crucible outer wall and sidepiece primary heater, described sidepiece primary heater and top primary heater are connected with primary heater electrode, described incubation cavity sidewall and incubation cavity base plate depart from formation gap.
The invention has the beneficial effects as follows: the present invention is by increasing portable secondary heater, in long brilliant process, keep the solid-liquid interface in portable secondary heater and quartz ceramic crucible to be in sustained height, under the drive of secondary heater electrode, move on along with boosting of crystalizing interface.Due to the velocity curve of the bottom-up movement of portable secondary heater and the brilliant velocity curve of length of seed of single crystal silicon in quartz ceramic crucible consistent, the heat effect of portable secondary heater can effectively stop the hot-fluid heat radiation of solid-liquid interface place quartz ceramic crucible sidewall, making the solid-liquid interface near quartz ceramic crucible wall is level or slightly protruding, thereby the generation of nucleus and inwardly growth on the quartz ceramic crucible wall in prevention solid-liquid interface forward position, the impact that the accurate monocrystalline crystalline structure that the seed crystal inducing action making produces is not newly produced crystal grain by quartz ceramic crucible wall place, the ratio of pure accurate monocrystalline crystal bar of growing is higher.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the present invention is further described.
Fig. 1 is structural representation of the present invention;
Wherein: Fig. 1, a kind of ingot casting thermal field schematic diagram of pure accurate monocrystalline completely of growing
Wherein, 1. incubation cavity sidewall pull bar, 2. incubation cavity top board, 3. quartz ceramic crucible, 4. plumbago crucible, 5. graphite helps grumeleuse, 6. lower furnace body, 7. pillar stiffener, 8. primary heater electrode, 9. gas cylinder, 10. secondary heater electrode running gear, 11. secondary heater electrodes, 12. upper furnace bodies, 13. sidepiece primary heaters, 14. silicon solution, 15. portable secondary heaters, 16. incubation cavity sidewalls, 17. silicon crystal, 18. incubation cavity base plates.
Embodiment
The present invention is further illustrated by reference to the accompanying drawings now.The schematic diagram that these accompanying drawings are simplification only illustrates basic structure of the present invention in a schematic way, so it only shows the formation relevant with the present invention.
As shown in Figure 1, a kind of ingot casting thermal field of the pure accurate monocrystalline of growing, there is upper furnace body 12, lower furnace body 6, upper furnace body 12, in the cavity that lower furnace body 6 forms, be provided with quartz ceramic crucible 3, quartz ceramic crucible 3 is placed in plumbago crucible 4, plumbago crucible 4 bottoms are provided with graphite and help grumeleuse 5, graphite helps grumeleuse 5 to be supported by pillar stiffener 7, in quartz ceramic crucible 3, be added with silicon solution 14, silicon solution 14 bottoms form silicon crystal 17 in long brilliant process, silicon solution 14 tops of quartz ceramic crucible 3 to upper furnace body 12 tops are provided with gas cylinder 9, plumbago crucible 4 is positioned at the incubation cavity sidewall 16 of bottom opening.
Quartz ceramic crucible 3 tops are provided with top primary heater, sidepiece primary heater 13 is between incubation cavity sidewall 16 and plumbago crucible 4 outer walls, portable secondary heater 15 is between plumbago crucible 4 outer walls and sidepiece primary heater 13, sidepiece primary heater 13 is connected with primary heater electrode 8 with top primary heater, incubation cavity sidewall 16 departs from and forms gap with incubation cavity base plate 18, and incubation cavity sidewall 16 tops are connected with 2 sealings of incubation cavity top board.
If quartz ceramic crucible 3 is outer, plumbago crucible 4 is not set, sidepiece primary heater 13 is between incubation cavity sidewall 16 and quartz ceramic crucible 3 outer walls, and portable secondary heater 15 is between quartz ceramic crucible 3 outer walls and sidepiece primary heater 13.
Portable secondary heater 15 is connected with secondary heater electrode 11, secondary heater electrode 11 is connected with secondary heater electrode running gear 10 through upper furnace body 12, secondary heater electrode running gear 10 is arranged on upper furnace body 12, secondary heater electrode running gear 10 drives portable secondary heater 15 to move up and down by secondary heater electrode 11, and the velocity curve of portable secondary heater 15 bottom-up movements is consistent with the brilliant velocity curve of length of quartz ceramic crucible 3 interior seed of single crystal silicon.
Portable secondary heater 15 be annular, and portable secondary heater 15 was around the outer wall wall of quartz ceramic crucible 3 one week.Secondary heater electrode 11 is three electrode bars that distribute along even circumferential, and three electrode bars are all connected with annular portable secondary heater 15.
Use-pattern one:
The power of portable secondary heater 15 is fixed as 3kw, the bottom-up translational speed of portable secondary heater 15 is consistent with the brilliant velocity curve of length of quartz ceramic crucible 3 interior seed of single crystal silicon, by 15cm/h to 10cm/h, the accurate monocrystalline crystal bar growing detects after evolution, all crystal bars all do not comprise common poly grains, and pure accurate monocrystalline crystal bar ratio has reached 100%.
Use-pattern two:
The power variation interval of portable secondary heater 15 is 3~10kw, the bottom-up translational speed of portable secondary heater 15 is consistent with the brilliant velocity curve of length of quartz ceramic crucible 3 interior seed of single crystal silicon, by 20cm/h to 10cm/h, the accurate monocrystalline crystal bar growing detects after evolution, and all crystal bars are the pure accurate monocrystalline crystal bar that does not comprise poly grains completely.
The present invention is by increasing portable secondary heater, keeps portable secondary heater 15 and the unified height of solid-liquid interface in quartz ceramic crucible 3 in long brilliant process, under the drive of secondary heater electrode 11, moves on along with boosting of crystalizing interface.Due to the velocity curve of portable secondary heater 15 bottom-up movements and the brilliant velocity curve of length of quartz ceramic crucible 3 interior silicon crystal consistent, the heat that portable secondary heater 15 sends has stoped the hot-fluid of quartz ceramic crucible 3 to sidewall, making the solid-liquid interface near quartz ceramic crucible 3 walls is level or slightly protruding, thereby the generation of nucleus and inwardly growth on quartz ceramic crucible 3 walls in prevention solid-liquid interface forward position, the impact that the accurate monocrystalline crystalline structure that the seed crystal inducing action making produces is not newly produced crystal grain by quartz ceramic crucible wall place, obtain 100% pure accurate single crystal structure, the ratio of pure accurate monocrystalline crystal bar of growing is higher.
Adopt after the present invention, 25 crystal bars of growth monocrystalline crystal bar that is all as the criterion, the earning rate of accurate monocrystalline crystal bar is 100%, and the earning rate of the accurate monocrystalline crystal bar of common ingot casting thermal field is only 36%, is three times of the earning rate of traditional quasi-monocrystalline silicon.Thereby greatly reduce the production cost of accurate monocrystalline crystal, improved the total quality of accurate monocrystalline crystal ingot.
The above-mentioned foundation desirable embodiment of the present invention of take is enlightenment, and by above-mentioned description, relevant staff can, within not departing from the scope of this invention technological thought, carry out various change and modification completely.The technical scope of this invention is not limited to the content on specification sheets, must determine its technical scope according to claim scope.