The terraced method rotation of temperature crucible crystal growth system
Technical field
The utility model relates to the crystal technique field, the terraced method rotation of particularly a kind of temperature crucible crystal growth system.
Background technology
China Patent No. is 200420082546.8 to have described the two heating of a kind of single crystalline of can effectively growing tgt crystal growth devices, similar with the conventional temperature gradient method, heating element has only a crucible part high in the crystal growing process, progressively make crystal growth by move heating element with appropriate speed, these class methods are effective during single crystal in growth, but can not realize that many crystal grow simultaneously.
Crystal growth system in the existing multiple crucible crystal growth technology generally adopts multi-crucible lowering method crystal growth system, by prolonging size of burner hearth in a direction, makes in the burner hearth and can hold many crystal growths simultaneously in this system.The accurate rectangle radial temperature field of Xing Chenging is acquisition initial successes such as quadrate crystal of lead tungstate in the growth outward appearance like this.In this descent method crystal growth system in the crystal burner hearth high-temperature zone be usually located at the above whole burner hearth district of crystal growth point, the upper temp of growth crucible is higher so in actual applications, crystal growth raw material and doping agent are in melted state, and mixing does not have volatile dopant such as La
2O
3The time raw material top reserve or be not fairly obvious to the crystal growth influence because of polycrystal raw material grows into the space that volume-diminished forms on solid top behind the monocrystalline, but lower at the growth fusing point, volatility is bigger as PbF
2During Deng dopant, dopant is serious evaporates into upper space doping may be realized hardly.And in the existing multi-crucible lowering method crystal growth technology crystal (as crystal of lead tungstate, Sb
2O
3Lead tungstate-doped crystal, Nb
2O
5Lead tungstate-doped crystal) the crucible bracing or strutting arrangement of growing system is under automatic control equipment control, can drive crucible as requested and move downward the realization crystal growth, but this crystal growing crucible bracing or strutting arrangement is merely able to drive growth crucible to move up and down, during crystal growth because the relative transfixion of melt with crystal, only exist natural convection and diffusion in the melt, its major impetus is particle concentration gradient in crystal growth interface place and the melt, thermograde and center of gravity gravitation.This relies on that PARTICLE TRANSPORT FROM speed is slow in the melt that natural convection and diffusion transport the growth particle, efficient is not high, in that growth components is simple, component ion effective segregation coefficient is approaching, growth interface place crystal forms and bath component is close, crystal growth can be competent at during the less demanding crystal of PARTICLE TRANSPORT FROM in to melt.Complicated when growth components, at the interface crystal form and bath component differ big, when component ion effective segregation coefficient has the crystal of significant difference, melt PARTICLE TRANSPORT FROM power scarce capacity can make the unwanted particle in particle, interface that the growth interface melt can not in time obtain crystal growth to be needed (as the gritty particle of impurities removal generation) in time transfer in the melt, the place accumulates gradually at the interface melt, concentration is crossed conference and is made the too much impurity of appearance in the crystal, even forms out-phase.These can cause in the crystal defective too much, even serious macroscopic defects such as out-phase wrap can occur, or can occur serious results such as dopant ion concentration distribution in crystal is inhomogeneous when the grow doping crystal, cause crystal mass to degenerate.
Be burner hearth that rectangular parallelepiped distributes in the multi-crucible lowering method growing system and can hold many even tens of crystal simultaneously and grow simultaneously, realize the purpose of multiple crucible crystal growth, the heating element that is positioned at hearth wall can satisfy the caloric requirement of crystal growth.It is the quadrate crystal growth that the asymmetric radial distribution of this accurate rectangle temperature field is suitable for outward appearance, whole crystal growing process carries out under very quiet condition, the crystal growth that effective segregation coefficient is more or less the same between, component not high for growth solute transmission requirement or dopant ion is favourable, to outward appearance be in the unfavorable and whole growth process of cylindrical crystal growth in the crucible melt keep relative motionless with crystal, lack forced convection, the solute transmission efficiency is not high, and being unfavorable for growing, effective segregation coefficient differs bigger crystal between component.
Summary of the invention
Technical problem to be solved in the utility model provides and a kind ofly can promote crystal doping, and makes doping tgt crystal growth system uniformly.
The technical scheme that the utility model adopted is:
The terraced method rotation of a kind of temperature crucible crystal growth system comprises crystal furnace, crucible and bracing or strutting arrangement thereof and temperature-control device, and wherein crystal furnace comprises body of heater, heating element and burner hearth; Body of heater comprises shell, insulating cotton layer, insulating brick-layer and flame retardant coating from outside to inside successively; The crucible bracing or strutting arrangement comprises lifting table, be positioned at a plurality of crucible guide pipe supports on the lifting table and the crucible guide pipe on the guide pipe support, what be connected with lifting table draws lower device, with draw lifting motor and the power supply that lower device is connected, be provided with securing gear between guide pipe support and the guide pipe, crucible places in the crucible guide pipe; The crucible bracing or strutting arrangement is rotatable many crucibles bracing or strutting arrangement, the lower end of each guide pipe support is provided with turning axle, turning axle runs through lifting table, the part that lifting table is stretched out in the turning axle lower end is connected with intermeshed gear respectively, one of them turning axle is than other rotation axial length, and the gear on this longer turning axle connects a rotating machine that is fixed on the lifting table by shaft coupling; Described flame retardant coating height is the 2/3-5/6 of burner hearth total height; Described heating element is positioned at burner hearth 1/4-1/2 and highly locates.
Because heating element only have be positioned at one deck that burner hearth 1/4-1/2 highly locate, and flame retardant coating height burner hearth in only be the 2/3-5/6 of burner hearth total height, leave a blank, like this in crystal furnace can formation four warm areas in actual applications by remaining part for the utility model.Be followed successively by first warm area, second warm area, three-temperature-zone and four-temperature region from top to bottom, growth crucible is placed in one when carrying out crystal growth, and the raw material of first temperature area does not melt; The second warm area raw material here is melted, and wherein the first and second warm area intersections are growth raw material fusing point place; The three-temperature-zone temperature is lower than the growth raw material fusing point, and the crystal here is in crystallization, wherein second and the three-temperature-zone intersection be crystal growth point temperature, the three-temperature-zone thermograde is big, and the motivating force of crystal structure can be provided; Nethermost four-temperature region temperature is low until ambient temperature bottom, and this zone is the good crystal of having grown.
Like this; in crystal growing process; part material fusing in the growth crucible; the part that being in crucible top does not have to melt is a blocks of solid; the volatilization of volatile gases in the melt below can suppressing or block; form solid envelope, and protection growth melt is unlikely to its bath composition because component nonstoichiometry volatilization makes melt composition depart from the proportioning of crystal growth requirement.And owing to adopt rotatable many crucibles bracing or strutting arrangement, when crystal growth, can regulate rotary shaft rotating speed and direction as required, make the crucible in the crucible guide pipe carry out the speed change rotation according to certain program, rigid crystals that grows in the growth and sidewall of crucible are synchronous with rotating machine under the drive of rotating guide tube mechanical rotation, because inertia effect, liquid melt and crystal and sidewall of crucible produce relative movement, produce with crystal pulling method similarly to the stirring action of melt, make melt produce forced convection, the generation of forced convection can improve greatly that material transports situation in the melt, the crystal interface in making crystal growth solid-liquid interface particle and growing and the exchange of particles of melt are separated kind, crystal in the growth can obtain the particle of needs, the unwanted particle that impurities removal produces can in time be discharged in the melt, and this is to improving perfection of crystal, it is very favourable to improve crystal mass.
Though for holding a plurality of simultaneously and even the dozens of crucible carries out multiple crucible crystal growth, burner hearth and vertical multi-crucible crystal growth system that native system adopts are similar, be the cuboid burner hearth, but because in crystal growing process, the crucible guide pipe is in rotating continuously, and good thermal insulation layer arranged between crucible and guide pipe, can cushion of the influence of the temperature variation of crucible guide tube wall, so the radial temperature in temperature field is a circular symmetry in the interior growth crucible of guide pipe to temperature field in the crucible at guide pipe center.Because thermograde is the main drive of crystal growth, the solid-liquid interface during symmetric radial temperature field helps growing is in radial symmetry, and crystal is grown the temperature-driven power that obtains in all directions and is similar, and improves the crystal mass of growth greatly.Therefore using can grow bath component relative complex, the oriented segregation coefficient of component ion of the utility model has certain difference or doped crystal, can also grow simultaneously to obtain existing many crucibles degrowth technology and be difficult to the rod-like crystal that obtains.
The beneficial effects of the utility model are:
The terraced method rotation of temperature of the present utility model crucible crystal growth system efficient temperature gradient is that the polycrystal of the interior melt of the crucible top of growth forms solid envelope above melt, suppress the volatilization of volatile component in the melt, be not only applicable to the to mix crystal growth of volatile doping agent, being applicable to too simultaneously mixes does not have the crystal growth of volatile doping agent.And the crucible and the guide pipe thereof of rotation can provide radially symmetric temperature field in the crucible, therefore adopt the utility model can effectively improve the quality of growing crystal, and can grow high-quality doped crystal, can also grow simultaneously obtains the rod-like crystal that existing many crucibles degrowth technology is difficult to acquisition.
Description of drawings
Fig. 1 is the utility model structural representation;
Fig. 2 is crucible and bracing or strutting arrangement enlarged view thereof.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in further detail:
The terraced method rotation of temperature of the present utility model crucible crystal growth system comprises as depicted in figs. 1 and 2: crystal furnace 1, and crucible 2 and bracing or strutting arrangement 3 thereof, wherein crystal furnace 1 comprises body of heater 4, heating element 5 and burner hearth 6; Body of heater 4 comprises shell 401, insulating cotton layer 402, insulating brick-layer 403 and flame retardant coating 404 from outside to inside successively; Crucible bracing or strutting arrangement 3 comprises lifting table 301, be positioned at a plurality of crucible guide pipe supports 302 on the lifting table 301 and the crucible guide pipe 303 on the guide pipe support, what be connected with lifting table 301 draws lower device 304, with draw lifting motor 305 and the power supply 306 that lower device 304 is connected, be provided with securing gear 307 between guide pipe support 302 and the guide pipe 303, crucible 2 places in the crucible guide pipe 303;
Described crucible bracing or strutting arrangement 3 is rotatable many crucibles bracing or strutting arrangements, the lower end of each guide pipe support 302 is provided with turning axle 308, turning axle runs through lifting table 301, the part that lifting table 301 is stretched out in turning axle 308 lower ends is connected with intermeshed gear 309 respectively, one of them turning axle is than other rotation axial length, and place the mid-way, the gear 309 on this longer turning axle connects a rotating machine 311 that is fixed on the lifting table by shaft coupling 310; Described flame retardant coating 404 highly is 2/3 of burner hearth 6 total heights; Described heating element 5 is positioned at 1/4 of burner hearth 6 and highly locates.The rotating speed and the direction of crucible are connected with digital frequency converter 312 between rotating machine 311 described in the present embodiment and the power supply 306 during for effective crystallization control.Flame retardant coating 404 highly can also be 3/4 or 5/6 of burner hearth total height in the burner hearth; Heating element 5 can also be positioned at 3/8 or 1/2 of burner hearth 6 and highly locate.For adapting to growth different crystal or doped crystal, also can change and use different heating elements, to satisfy the different crystal of growth or the needs of doped crystal according to different crystal fusing point and Tc.
But in actual applications, the introduction of rotatable crucible bracing or strutting arrangement also can produce a kind of counter productive in crystal growth system, and the guide pipe of rotation can produce air-flow upwards in burner hearth, and the fast more this effect of rotating speed is just obvious more.The guide pipe of air-flow and rotation all can exert an influence to the temperature field in the burner hearth, and especially radially bigger change can take place the shape of isothermal surface, and the air-flow that produces along guide tube wall can make the heat transfer of guide pipe accelerate.These influences all can be to temperature field distribution generation effect in the crucible, the radial symmetry of solid-liquid interface in the influence growth.These influences also can adopt the thickness of thickening the guide pipe inner thermal insulating layer to reduce the influence of this unfavorable factor along with the speed of rotation of guide pipe reduces reduction rapidly.