阅读说明：本技术 一种泡生法蓝宝石生长热场装置 (Thermal field device for sapphire growth by kyropoulos method ) 是由 何明珠 杭寅 张连翰 蔡双 朱影 潘世烈 赵兴俭 韦建 于 2019-09-16 设计创作，主要内容包括：本发明公开了一种蓝宝石晶体生长炉的温场结构和设计,旨在提供一种性能更加优异的热场,应用于生长更大尺寸蓝宝石晶体,该装置主要包括炉体、坩埚、上反射屏、侧反射屏、加热器等主体部件。通过加热器、上反射屏、侧反射屏、坩埚及下反射屏的合理布局,使坩埚内温场呈现中心温度低、边缘温度高的连续分布,适合生长高质量、大尺寸的蓝宝石晶体。(The invention discloses a temperature field structure and design of a sapphire crystal growth furnace, and aims to provide a thermal field with more excellent performance, which is applied to growing sapphire crystals with larger size. Through the reasonable layout of the heater, the upper reflecting screen, the side reflecting screen, the crucible and the lower reflecting screen, the temperature field in the crucible is in continuous distribution with low central temperature and high edge temperature, and the method is suitable for growing high-quality and large-size sapphire crystals.)

1. A thermal field device of a kyropoulos sapphire crystal growth furnace is characterized by mainly comprising a furnace body, a crucible, a heater and a heat preservation component, wherein the heat preservation component is made of a multilayer metal plate made of tungsten or molybdenum materials and comprises an upper reflecting screen (1), a side reflecting screen (2) and a bottom reflecting screen (8); the crucible sets up in semi-enclosed tungsten bucket (4), and the lower part is held in the palm by the crucible and is accepted, and support column (7) pass end reflecting screen (8) and heater (5) and hold in the palm with the crucible and be connected (6), go up the reflecting screen lower part and be equipped with the electrode, meet and be fixed in the side reflecting screen on heater (5) edgewise, whole furnace body forms enclosed construction.

2. The thermal field apparatus of the kyropoulos sapphire crystal growth furnace according to claim 1, wherein the electrode at the lower part of the upper reflecting screen is a tungsten electrode (11).

3. The thermal field device of the kyropoulos sapphire crystal growth furnace according to claim 1, wherein the middle of the base (10) and the bottom reflecting screen (8) is filled with an alumina hollow sphere (9).

4. The thermal field device of the kyropoulos sapphire crystal growth furnace according to claim 1, wherein the heater is of an all-tungsten welding structure, and the tungsten electrode (11), the tungsten ring (12) and the heater (5) are connected together by vacuum welding.

Technical Field

The invention relates to a sapphire crystal growth device, in particular to a sapphire thermal field device by a kyropoulos method, and belongs to the technical field of crystal preparation.

Background

Sapphire crystals are used as key components in the current semiconductor lighting industry, are important substrate materials of blue light and white light LEDs, and the large-size and high-quality growth preparation of the sapphire crystals is the basis of industrial development. At present, various methods are used for realizing the growth and preparation of sapphire crystals, including a kyropoulos method, a heat exchange method, a mold guiding method, a pulling method, a crucible descending method and the like. The kyropoulos method enables the growth of sapphire crystals having a large size and is relatively inexpensive in equipment cost, and is considered to be the most suitable method for mass production of sapphire crystals. In the conventional kyropoulos method, as in patent documents with publication numbers CN105088333A and CN205603721U, the heating elements of the device are all made of tungsten materials and are woven into a cage structure with low and high heating value; the cooling device adopts a water-cooled copper electrode, a large number of gaps exist among the heater, the side reflecting screen, the heater and the crucible, a large number of heat is radiated onto the water-cooled electrode and the furnace cover under the vacuum condition and is carried away by water, so that the edge temperature of the crucible is low, the transverse temperature gradient in the furnace is small, and the phenomenon is more obvious when the diameter of the sapphire crystal is larger. Under the temperature field distribution mode, heat is converted from being led out mainly through the seed rod heat exchanger to being led out mainly through the crucible wall, the spontaneous nucleation tendency of the crucible wall is increased, once the condition of spontaneous nucleation is achieved, a large number of spontaneous nucleation growth can be carried out from the crucible wall, the single crystal growth mode which is downward in sequence from the upper part and the seed crystal core is converted into a polycrystal growth mode from the crucible wall to the center melt, and therefore the complete failure of single crystal growth is caused.

Disclosure of Invention

Aiming at the problem of small transverse gradient of a sapphire crystal growth temperature field, the invention provides a new design for a thermal field of a sapphire crystal grown by a kyropoulos method, and aims to provide a thermal field with more advantageous radial temperature gradient.

The technical solution of the invention is as follows:

a thermal field device of a kyropoulos sapphire crystal growth furnace mainly comprises a furnace body, a crucible, a heater and a heat preservation component, wherein the heat preservation component is made of a multilayer metal plate made of tungsten or molybdenum materials and comprises an upper reflecting screen, a side reflecting screen and a bottom reflecting screen; the crucible is arranged in the semi-closed tungsten barrel, the lower part of the crucible is supported by a crucible support, and the support column penetrates through the bottom reflecting screen and the heater to be connected with the crucible support; the tungsten electrode at the lower part of the upper reflecting screen is connected with the upper end of the heater and is fixed on the side reflecting screen, and the whole furnace body forms a closed structure. The middle of the base and the bottom reflecting screen is filled with alumina hollow balls, the heater adopts a full-tungsten welding structure, and the tungsten electrode, the tungsten ring and the heater are welded together through vacuum welding.

According to the kyropoulos sapphire thermal field device provided by the invention, no gap with an opening exists among the heater, the upper reflecting screen and the side reflecting screen, so that heat is not easy to dissipate; the tungsten ring and the tungsten electrode are used for replacing a traditional water-cooled copper ring copper electrode structure, so that the loss of heat at the top is reduced, and the radial temperature gradient at the top is improved; the heat preservation effect is effectively enhanced by the full-tungsten vacuum welding mode; the alumina hollow ball filled at the bottom has larger temperature field inertia, and can improve the stability of the heat preservation system. The temperature field in the furnace is in a continuous increasing distribution mode with low center and high edge, can avoid the bad phenomenon of crucible wall crystallization caused by radial temperature difference in the crystal growth process, and is suitable for growing high-quality and large-size sapphire crystals.

Drawings

FIG. 1 is a prior art diagram of a conventional thermal field simulation;

FIG. 2 is a diagram of a thermal field simulation provided by the present invention;

FIG. 3 is a schematic diagram of a kyropoulos sapphire thermal field apparatus:

the device comprises a shell, a heater, a crucible cover, a tungsten barrel, a heater, a crucible support, a support column, a bottom reflecting screen, an alumina hollow ball, a base, a heater electrode and a tungsten ring, wherein 1 is the upper reflecting screen, 2 is the side reflecting screen, 3 is the crucible cover, 4 is the tungsten barrel, 5 is the heater, 6 is the crucible support, 7 is the support column, 8 is the bottom reflecting screen, 9 is the alumina hollow ball, 10 is the base, 11 is the;

FIG. 4 is a schematic view of a heating element, in which 13 is a junction between the heating element and a motor, 14 is the heating element, and 15 is a support frame.

Detailed Description

The device is further described with reference to the following specific figures and examples.

Fig. 1 is a simulation of a thermal field in the prior art. The data in the figure is the temperature distribution from the center of the crucible to the crucible wall. In this prior art, the temperature at the center of the crucible is higher than the temperature at the wall of the crucible at the initial stage of crystal growth until the temperature at the center of the crucible is lower than the temperature at the wall of the crucible at the later stage of crystal growth.

FIG. 2 is a simulation of the thermal field of the present invention, in which it can be seen that the temperature at the center of the crucible is always kept slightly lower than the temperature of the crucible wall from the initial stage of growth.

As shown in figure 3, the invention comprises a furnace body, a crucible cover (3), a tungsten barrel (4), an upper reflecting screen (1), a side reflecting screen (2), a bottom reflecting screen (8), a heater (5) and other main body components, wherein the crucible is arranged in the tungsten barrel (4), and a support column (7) is arranged at the bottom in the furnace. The supporting column (7) sequentially penetrates through the bottom reflecting screen (8) and the heater (5) to be connected with the crucible support (6) to receive the crucible. The reflecting screen is made by arranging a plurality of layers of tungsten plates at equal intervals, the upper reflecting screen (1) is not contacted with the side reflecting screen (2), and the tungsten electrode (11) is positioned at the lower part of the upper reflecting screen (1) and is fixed on the side reflecting screen (2) by punching. One end of the tungsten electrode (11) is connected with the heater (5). The middle of the base (10) and the bottom reflecting screen (8) is filled with alumina hollow balls (9). The heater (5) adopts a full tungsten welding structure and is arranged in the tungsten barrel (4). The tungsten electrode (11) and the heating element (5) of the tungsten ring (12) are connected together by vacuum welding.