Deslagging device for germanium single crystal growth

Abstract

A slag removal device for germanium single crystal growth comprises a furnace body, a guide cylinder, a heat preservation cylinder, a scum container, a control part and a graphite crucible, the furnace body comprises a main chamber and an auxiliary chamber, the auxiliary chamber is arranged at the top of the main chamber, and a suspended seed crystal clamp penetrates through the auxiliary chamber from top to bottom to enter the main chamber; the bottom of the main chamber is provided with a console, a graphite crucible and a heat preservation cylinder; a control piece is arranged on a slope surface on one side of the upper part of the main chamber and connected with one end of a control rod extending into the main chamber, a sealing ring is arranged at an opening of the control rod extending into the main chamber, and a scum container is suspended at the other end of the control rod; an observation window is formed in the slope surface of the other side of the main chamber. The device can remove slag floating on the surface of a melt in the crystal growth process, and prevents the floating slag from entering a solid-liquid interface to cause crystal change of growing germanium crystals; in the single crystal growth process, the auxiliary chamber does not need to be opened, so that the germanium melt is prevented from being secondarily polluted or oxidized.

Description

Technical Field

[0001] The utility model belongs to the technical field of germanium crystal growth, and particularly relates to a device for removing scum on the surface of a melt during the growth process of germanium single crystals. Background Technique

[0002] Due to its unique properties, germanium single crystal materials have indispensable applications in the fields of infrared optics and space solar cells. So far, in the preparation of germanium single crystals, the Czochralski method is mainly used. During the growth process of germanium single crystals, it is inevitable that scum will form on the surface of the germanium melt. The conventional method for removing scum is to use a seed crystal to descend to the surface of the melt and grow the crystal in a rapid shoulder-opening manner. The grown crystal adheres to the scum on the surface of the melt, and the scum is removed through multiple up-and-down lifting and adhesion.

[0003] This method is widely used in the field of germanium single crystal growth and has good results. However, there are still deficiencies:

[0004] First, with the repeated use of the graphite crucible, the surface oxidation gradually becomes serious, that is, the inner surface becomes rougher and rougher. The rough surface will adhere to the scum. During the shoulder-opening, shoulder-turning, equal-diameter, and finishing processes of germanium single crystals, a large area of the inner surface of the crucible is exposed, and the scum will fall off again and enter the melt, causing crystal variation at the solid-liquid interface during crystal growth.

[0005] Second, after the proposed scum is cooled, it is necessary to open the auxiliary chamber to remove the slag head, and part of the oxygen and dust particles enter the single crystal furnace, polluting the germanium melt. Content of the Utility Model

[0006] The utility model provides a device for removing scum on the surface of a melt for growing germanium single crystals. As a supplement or improvement to the conventional seed crystal adhesion slag removal method, it can further remove the newly entered scum on the surface of the melt.

[0007] A slag removal device for growing germanium single crystals, characterized in that it includes a furnace body, a flow guide cylinder, a heat preservation cylinder, a scum container, a control member, and a graphite crucible. The furnace body includes a main chamber and an auxiliary chamber. The main chamber is cylindrical and is provided with a furnace cover that gradually narrows upward. The auxiliary chamber is arranged on the top of the furnace cover. An opening and closing door is provided on the side of the auxiliary chamber. The suspended seed crystal clamp passes through the auxiliary chamber from top to bottom and enters the main chamber; a control console is arranged at the bottom of the main chamber. A lifting mechanism and a power supply are arranged inside the control console. A graphite crucible is installed on the lifting mechanism. A heater is arranged outside the graphite crucible and is electrically connected to the power supply inside the control console. The control console and the heater are externally sleeved with a heat preservation cylinder. A flow guide cylinder is arranged at the center of the top of the heat preservation cylinder; a control member is arranged on one side of the furnace cover of the main chamber and is connected to one end of a control rod extending into the main chamber. A sealing ring is arranged at the opening where the control rod extends into the main chamber. The other end of the control rod suspends the scum container; an observation window is opened on the other slope surface of the main chamber.

[0008] The beneficial effects of the present utility model are as follows: By operating the control member, the dross container is used to hold the dross on the surface of the melt. The dross container is lifted up and down multiple times so that the cooled dross adheres to the small amount of fine dross remaining on the surface of the melt until there is no dross on the surface of the melt and it presents a bright and transparent form; during crystal growth, if dross is found on the surface of the melt, the dross container can be used again for dross removal operation. According to actual needs, the seed crystal is lifted completely out of the molten metal surface by the seed crystal clamp, and crystal growth is continued after the dross removal operation is completed, and the crystal growth operation can also be completed without changing while removing dross. The present utility model can remove the dross floating on the surface of the melt during crystal growth, preventing the dross from entering the solid-liquid interface and causing the growing germanium crystal to change crystal; during single crystal growth, the secondary chamber does not need to be opened, avoiding secondary contamination or oxidation of the germanium melt; compared with the conventional method of using the seed crystal to attach dross during shoulder formation, the dross removal efficiency is faster and more efficient, and it is also more flexible and can be used during crystal growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic structural diagram of a dross removal device for germanium single crystal growth.

[0010] Wherein: 1 - secondary chamber, 2 - main chamber, 3 - seed crystal clamp, 4 - flow guide cylinder, 5 - heat preservation cylinder, 6 - dross container, 7 - control member, 70 - control rod, 8 - graphite crucible, 9 - heater, 10 - observation window, 11 - sealing ring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0011] A dross removal device for germanium single crystal growth includes a furnace body, a flow guide cylinder 4, a heat preservation cylinder 5, a dross container 6, a control member 7 and a graphite crucible 8. The furnace body includes a main chamber 2 and a secondary chamber 1. The main chamber 2 is cylindrical, and there is a furnace cover that gradually narrows upward. The secondary chamber 1 is arranged on the top of the furnace cover of the main chamber 2. There is an opening and closing door on the side of the secondary chamber 2. The seed crystal clamp 3 is suspended above by a crane and passes through the secondary chamber 2 from top to bottom and enters the main chamber 1. A control console is arranged at the bottom of the main chamber 2. An elevating mechanism and a power supply are arranged in the control console. The graphite crucible 8 is installed on the elevating mechanism. A heater 9 is arranged outside the graphite crucible 8 and is electrically connected to the power supply in the control console. The control console and the heater are sleeved with a heat preservation cylinder 5. A flow guide cylinder 4 is arranged at the center of the top of the heat preservation cylinder 5; a control member 7 is arranged on one side slope of the upper part of the main chamber 2 and is connected to one end of a control rod 70 extending into the main chamber. A sealing ring 11 is arranged at the opening where the control rod 70 extends into the main chamber 2, and a dross container 6 is suspended at the other end of the control rod 70; an observation window 10 is opened on the other side slope of the main chamber 2.

[0012] During use: (1) Open the top covers of the secondary chamber 1 and the main chamber 2, load a zone-melted germanium ingot into the graphite crucible 8, install the flow guide cylinder 4, close the furnace body, and then evacuate and introduce a protective gas;

[0013] (2)Turn on the power supply to heat the heater 9, and the heat is radiated to the graphite crucible 8 and conducted to the zone-melted germanium ingot to melt it into a metal melt;

[0014] (3)Lower the position of the graphite crucible 8 to facilitate observing the situation inside the main chamber 2 through the observation window 10;

[0015] (4)Control the thermal field inside the main chamber 2 by regulating the heater 9, so that the scum on the surface of the metal melt is concentrated in the middle area. Operate the control member 7 to make the scum container 6 hold the surface scum; Lift the scum container 6 up and down multiple times, and use the cooled scum to adhere to the remaining small pieces of fine scum on the surface of the metal melt until there is no scum on the surface of the metal melt and it presents a bright and transparent form;

[0016] (5)After slag removal is completed, operate the control member 7 to move the scum container 6 upward so as not to affect the crystal growth operation;

[0017] (6)Raise the position of the graphite crucible 8 through the lifting mechanism and lower the position of the seed crystal clamp 3, so that the seed crystal on the seed crystal clamp 3 starts preheating and crystal seeding operations;

[0018] (7)During crystal growth, when scum is found on the surface of the metal melt, use the scum container 6 to perform slag removal operations again. According to actual needs, lift the seed crystal completely out of the melt surface, and continue crystal growth after the slag removal operation is completed, or slag removal can also be completed without changing the crystal growth operation.

Claims

1. A slag removal device for growing germanium single crystals, characterized in that: It includes a furnace body, a draft tube, a heat preservation cylinder, a dross container, a control component and a graphite crucible. The furnace body includes a main chamber and a secondary chamber. The main chamber is cylindrical and is provided with a furnace cover that gradually narrows upward. The secondary chamber is arranged at the top of the furnace cover. An opening and closing door is provided on the side of the secondary chamber. The suspended seed crystal clamp passes through the secondary chamber from top to bottom and enters the main chamber. A control console is arranged at the bottom of the main chamber. A lifting mechanism and a power supply are arranged inside the control console. The graphite crucible is installed on the lifting mechanism. A heater is arranged on the outside of the graphite crucible and is electrically connected to the power supply inside the control console. The control console and the heater are sleeved with a heat preservation cylinder. A draft tube is arranged at the center of the top of the heat preservation cylinder. A control component is arranged on one side of the furnace cover of the main chamber and is connected to one end of a control rod extending into the main chamber. A sealing ring is arranged at the opening where the control rod extends into the main chamber. The other end of the control rod suspends the dross container. An observation window is opened on the slope on the other side of the main chamber.

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