CN105525355A - In-situ annealing process for large-size sapphire crystal - Google Patents
In-situ annealing process for large-size sapphire crystal Download PDFInfo
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Abstract
The invention relates to the technical field of processing of crystal materials and discloses an in-situ annealing process for a large-size sapphire crystal. According to the invention, after completion of growth of a sapphire crystal via a Kyropoulos method, the sapphire crystal is maintained in-situ, the vacuum degree of a single crystal furnace is maintained, and five stages of annealing is carried out so as to obtain the sapphire crystal with stable performance and high quality. Through heat preservation and annealing in stages, the dislocation density of large-size sapphire can be effectively reduced; stress in the crystal can be maximally eliminated; crystal lattice is improved; crystal defects are reduced; and the integral quality of the sapphire crystal is improved.
Description
Technical field
The present invention relates to crystalline material processing technique field, particularly relate to a kind of large size sapphire crystal in-situ annealing technique.
Background technology
Sapphire has excellent physics, machinery, chemistry and infrared light transmission performance, is the material that the fields such as microelectronics, aerospace, military project are badly in need of always.The product of current industrial comparative maturity is the 35kg level sapphire utilizing kyropoulos to grow, but due to reasons such as crystal utilization ratio, production costs, the sapphire crystal of 35kg level is being eliminated by industry gradually, large size sapphire crystal more than market demand 75kg weight category, thus be lowered into and originally obtained benefit.Because sapphire crystal growth cycle is long, crystalline size is large, a large amount of internal stresss can be there is in crystal, lattice distortion is serious, optical homogeneity is poor, needs to carry out rational anneal to crystal, can effectively eliminate elastic deformation and crystal lattice distortion, reduce the thermal stresses of crystal, reduce lattice defect.Owing to there is temperature stratification in stove, temperature stratification is little on the impact of small size crystal bar, negligible during annealing, but for large size crystal bar, because crystal bar two ends distance is longer, temperature stratification causes the temperature difference at large size crystal bar two ends comparatively large (for the temperature difference at small size crystal bar two ends), if adopt the annealing process that small size crystal bar is identical, then the sapphire lattice finally obtained distorts, and crystal dislocation density is high, optical homogeneity reduces, and even cracking etc. occurs in end.
China Patent Publication No. CN101182646A, publication date on May 21st, 2008, disclose a kind of device adopting heat-exchanging method growing hemisphere type crystal, the bottom center outside hemispheric crucible contacts continuous electrical heat exchanger, is provided with the pneumatic tube of delivering gas in the heat exchanger of tubulose.Use the method for this device growing hemisphere type crystal, mainly comprise the following steps: 1) resistance heater heats up, and makes melting sources in crucible, in heat exchanger, pass into helium gas cooling seed crystal simultaneously; 2) by the flow of helium in the power of control heater and heat exchanger, make the raw material in crucible fully can be fused into melt, and seed crystal can not be melted; 3) thermograde of melt is controlled by graphite heater, and crystal temperature gradient is controlled by heat exchanger; Increase the gas flow of heat exchanger, reduce the temperature of seed crystal, the solid-liquid interface of crystal growth with the cambered surface of nearly sphere to external expansion; 4) after crystal growth completes, crystal is cooled to room temperature, completes hemisphere type crystal growth.Its weak point is, in temperature-fall period, can there is a large amount of internal stresss in crystal, and lattice distortion is serious, and optical homogeneity is poor.
Summary of the invention
The present invention there are differences in order to the annealing initial temperature solving large size sapphire crystal two ends of the prior art, thus cause crystal two ends mass discrepancy large, a large amount of internal stress, lattice distortion is there is in crystal, even there is the defects such as crackle in end, provide a kind of internal stress that effectively can reduce large size sapphire crystal, reduce lattice defect, improve the large size sapphire crystal in-situ annealing technique of crystal mass.
To achieve these goals, the present invention adopts following technical scheme:
A kind of large size sapphire crystal in-situ annealing technique, after kyropoulos growing sapphire crystal completes, sapphire crystal keeps original position, and keep the vacuum tightness of single crystal growing furnace, annealing process comprises following double teacher;
First stage: improve heater power, with the speed of 15-20 DEG C/h, the temperature in single crystal growing furnace is raised 2-3 DEG C; Reduce heating power again, with the speed of 5-10 DEG C/h, the temperature in single crystal growing furnace is reduced 3-4 DEG C, insulation 0.5h;
Subordinate phase: reduce heating power, with the speed of 20-25 DEG C/h, the temperature in single crystal growing furnace is reduced to 1750 DEG C, insulation 4h;
Phase III: improve heating power, with the speed of 10-15 DEG C/h, the temperature in single crystal growing furnace is improved 1-2 DEG C, insulation 0.5h; Reduce heating power again, with the speed of 3-5 DEG C/h, the temperature in single crystal growing furnace is reduced 2-3 DEG C, insulation 0.5h;
Fourth stage: reduce heating power, with the speed of 25-30 DEG C/h, the temperature in single crystal growing furnace is reduced to 800 DEG C, insulation 4h;
Five-stage: reduce heating power, with the speed of 30-40 DEG C/h, single crystal growing furnace is lowered the temperature, until heater power is zero, take out sapphire crystal after cooling.
In above-mentioned double teacher, wherein subordinate phase, fourth stage, five-stage are pure annealing stage, adopt step heat preservation annealing can effectively reduce the dislocation sealing of large-size sapphire, eliminate crystal internal stress to greatest extent, improvement lattice, reduce lattice defect, improve the total quality of sapphire crystal; Wherein the first stage be to annealing before the temperature correction stage, owing to there is the temperature difference between the upper and lower two ends of large size sapphire crystal, first stage is first rapidly heated, then lower the temperature with extremely slow speed, after cooling, large size sapphire crystal bulk temperature is more even, and when ensureing to anneal, the conditional consistency of large size sapphire crystal different sites is better, thus the sapphire crystal inside obtained after annealing is more even, quality conformance is good; Annealing through subordinate phase is incubated, and also can form temperature stratification in single crystal growing furnace, now by the adjustment of phase III, thus ensures fourth stage Initial Annealing, each position of large-size sapphire consistent; The time of first stage and phase III is negligible for whole annealing process total time, therefore can not affect annealing efficiency.
As preferably, in the first stage, rotate sapphire crystal with the speed of 0.5-1rpm, the first stage terminates rear sapphire and stops the rotation.To rotate sapphire lower than the speed of rotation in sapphire crystallization process, sapphire bulk temperature can be made to distribute more even, reduce the centrifugal impact on crystal rotated simultaneously to greatest extent; Due to the right cylinder of the blue precious also non-fully rule of large size, its axle center and rotation center are also difficult to overlap completely, and after the first stage terminates, sapphire crystal internal structure is not also stablized, therefore the first stage terminate after to stop operating sapphire, the impact of centrifugal force on sapphire internal structure of stopping the rotation.
As preferably, in the phase III, rotate sapphire crystal with the speed of 1-1.5rpm.Through the annealing of subordinate phase, now sapphire internal structure tends towards stability, and relatively improves rotating speed, makes large size sapphire crystal internal temperature more even.
As preferably, in fourth stage, rotate sapphire crystal with the speed of 1.5-2.5rpm; At five-stage, rotate sapphire crystal with the speed of 2.5-4rpm.Fourth stage, five-stage improve rotating speed successively, make the annealing temperature of large-size sapphire more even.
As preferably, at five-stage, when heater power is zero, pass into rare gas element, be quickly cooled to room temperature.
As preferably, described rare gas element is argon gas, and its force value is 1.2-1.5 normal atmosphere.
Therefore, the present invention has following beneficial effect: (1) adopts step heat preservation annealing can effectively reduce the dislocation sealing of large-size sapphire, eliminates crystal internal stress to greatest extent, improvement lattice, reduce lattice defect, improve the total quality of sapphire crystal; (2) at subordinate phase, fourth stage Initial Annealing, large-size sapphire internal temperature is regulated, make Initial Annealing temperature more consistent, ensure that annealing starting condition is consistent, improve total quality consistence and stability.
Embodiment
Below in conjunction with embodiment, the invention will be further described:
Embodiment 1: a kind of large size sapphire crystal in-situ annealing technique, after kyropoulos growing sapphire crystal completes, sapphire crystal keeps original position, and keep the vacuum tightness of single crystal growing furnace, annealing process comprises following double teacher;
First stage: improve heater power, rotate sapphire crystal with the speed of 0.5rpm, with the speed of 15 DEG C/h, the temperature in single crystal growing furnace is raised 2 DEG C; Reduce heating power again, with the speed of 5 DEG C/h, the temperature in single crystal growing furnace is reduced by 3 DEG C, insulation 0.5h, the first stage terminates rear sapphire and stops the rotation;
Subordinate phase: reduce heating power, with the speed of 20 DEG C/h, the temperature in single crystal growing furnace is reduced to 1750 DEG C, insulation 4h;
Phase III: improve heating power, in the phase III, rotate sapphire crystal with the speed of 1rpm, with the speed of 10 DEG C/h, the temperature in single crystal growing furnace is improved 1 DEG C, insulation 0.5h; Reduce heating power again, with the speed of 3 DEG C/h, the temperature in single crystal growing furnace is reduced by 2 DEG C, insulation 0.5h;
Fourth stage: reduce heating power, rotates sapphire crystal with the speed of 1.5rpm, with the speed of 25 DEG C/h, the temperature in single crystal growing furnace is reduced to 800 DEG C, insulation 4h;
Five-stage: reduce heating power, rotates sapphire crystal with the speed of 2.5rpm, lowers the temperature with the speed of 30 DEG C/h to single crystal growing furnace, until heater power is zero, then passing into force value is 1.2 atmospheric argon gas, is quickly cooled to room temperature, takes out sapphire crystal after cooling.
Embodiment 2: a kind of large size sapphire crystal in-situ annealing technique, after kyropoulos growing sapphire crystal completes, sapphire crystal keeps original position, and keep the vacuum tightness of single crystal growing furnace, annealing process comprises following double teacher;
First stage: improve heater power, rotate sapphire crystal with the speed of 0.7rpm, with the speed of 18 DEG C/h, the temperature in single crystal growing furnace is raised 2.5 DEG C; Reduce heating power again, with the speed of 8 DEG C/h, the temperature in single crystal growing furnace is reduced by 3.5 DEG C, insulation 0.5h, the first stage terminates rear sapphire and stops the rotation;
Subordinate phase: reduce heating power, with the speed of 23 DEG C/h, the temperature in single crystal growing furnace is reduced to 1750 DEG C, insulation 4h;
Phase III: improve heating power, in the phase III, rotate sapphire crystal with the speed of 1.3rpm, with the speed of 13 DEG C/h, the temperature in single crystal growing furnace is improved 1.5 DEG C, insulation 0.5h; Reduce heating power again, with the speed of 4 DEG C/h, the temperature in single crystal growing furnace is reduced by 2.5 DEG C, insulation 0.5h;
Fourth stage: reduce heating power, rotates sapphire crystal with the speed of 2rpm, with the speed of 28 DEG C/h, the temperature in single crystal growing furnace is reduced to 800 DEG C, insulation 4h;
Five-stage: reduce heating power, rotates sapphire crystal with the speed of 3.2rpm, lowers the temperature with the speed of 35 DEG C/h to single crystal growing furnace, until heater power is zero, then passing into force value is 1.4 atmospheric argon gas, is quickly cooled to room temperature, takes out sapphire crystal after cooling.
Embodiment 3: a kind of large size sapphire crystal in-situ annealing technique, after kyropoulos growing sapphire crystal completes, sapphire crystal keeps original position, and keep the vacuum tightness of single crystal growing furnace, annealing process comprises following double teacher;
First stage: improve heater power, rotate sapphire crystal with the speed of 1rpm, with the speed of 20 DEG C/h, the temperature in single crystal growing furnace is raised 3 DEG C; Reduce heating power again, with the speed of 10 DEG C/h, the temperature in single crystal growing furnace is reduced by 4 DEG C, insulation 0.5h, the first stage terminates rear sapphire and stops the rotation;
Subordinate phase: reduce heating power, with the speed of 25 DEG C/h, the temperature in single crystal growing furnace is reduced to 1750 DEG C, insulation 4h;
Phase III: improve heating power, in the phase III, rotate sapphire crystal with the speed of 1.5rpm, with the speed of 15 DEG C/h, the temperature in single crystal growing furnace is improved 2 DEG C, insulation 0.5h; Reduce heating power again, with the speed of 5 DEG C/h, the temperature in single crystal growing furnace is reduced by 3 DEG C, insulation 0.5h;
Fourth stage: reduce heating power, rotates sapphire crystal with the speed of 2.5rpm, with the speed of 30 DEG C/h, the temperature in single crystal growing furnace is reduced to 800 DEG C, insulation 4h;
Five-stage: reduce heating power, rotates sapphire crystal with the speed of 4rpm, lowers the temperature with the speed of 40 DEG C/h to single crystal growing furnace, until heater power is zero, then passing into force value is 1.5 atmospheric argon gas, is quickly cooled to room temperature, takes out sapphire crystal after cooling.
Claims (6)
1. a large size sapphire crystal in-situ annealing technique, is characterized in that, after kyropoulos growing sapphire crystal completes, sapphire crystal keeps original position, and keep the vacuum tightness of single crystal growing furnace, annealing process comprises following double teacher;
First stage: improve heater power, with the speed of 15-20 DEG C/h, the temperature in single crystal growing furnace is raised 2-3 DEG C; Reduce heating power again, with the speed of 5-10 DEG C/h, the temperature in single crystal growing furnace is reduced 3-4 DEG C, insulation 0.5h;
Subordinate phase: reduce heating power, with the speed of 20-25 DEG C/h, the temperature in single crystal growing furnace is reduced to 1750 DEG C, insulation 4h;
Phase III: improve heating power, with the speed of 10-15 DEG C/h, the temperature in single crystal growing furnace is improved 1-2 DEG C, insulation 0.5h; Reduce heating power again, with the speed of 3-5 DEG C/h, the temperature in single crystal growing furnace is reduced 2-3 DEG C, insulation 0.5h;
Fourth stage: reduce heating power, with the speed of 25-30 DEG C/h, the temperature in single crystal growing furnace is reduced to 800 DEG C, insulation 4h;
Five-stage: reduce heating power, with the speed of 30-40 DEG C/h, single crystal growing furnace is lowered the temperature, until heater power is zero, take out sapphire crystal after cooling.
2. large size sapphire crystal in-situ annealing technique according to claim 1, is characterized in that, in the first stage, rotate sapphire crystal with the speed of 0.5-1rpm, the first stage terminates rear sapphire and stops the rotation.
3. large size sapphire crystal in-situ annealing technique according to claim 1 and 2, is characterized in that, in the phase III, rotates sapphire crystal with the speed of 1-1.5rpm.
4. large size sapphire crystal in-situ annealing technique according to claim 3, is characterized in that, in fourth stage, rotates sapphire crystal with the speed of 1.5-2.5rpm; At five-stage, rotate sapphire crystal with the speed of 2.5-4rpm.
5. large size sapphire crystal in-situ annealing technique according to claim 1, is characterized in that, at five-stage, when heater power is zero, passes into rare gas element, is quickly cooled to room temperature.
6. large size sapphire crystal in-situ annealing technique according to claim 5, is characterized in that, described rare gas element is argon gas, and its force value is 1.2-1.5 normal atmosphere.
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| CN106435741A (en) * | 2016-09-23 | 2017-02-22 | 江苏吉星新材料有限公司 | Large-size sapphire annealing process |
| CN107541785A (en) * | 2017-09-12 | 2018-01-05 | 中国电子科技集团公司第四十六研究所 | A kind of in-situ annealing technique of aluminum nitride crystal |
| CN110512287A (en) * | 2019-09-12 | 2019-11-29 | 江苏吉星新材料有限公司 | A kind of 4 inch sapphire crystal method for annealing |
| CN111155173A (en) * | 2018-11-07 | 2020-05-15 | 中科钢研节能科技有限公司 | Sapphire and annealing method of sapphire crystal |
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| CN111155173A (en) * | 2018-11-07 | 2020-05-15 | 中科钢研节能科技有限公司 | Sapphire and annealing method of sapphire crystal |
| CN111155173B (en) * | 2018-11-07 | 2021-07-23 | 国宏中晶集团有限公司 | Sapphire and annealing method of sapphire crystal |
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