A single crystal furnace is a device that uses a graphite heater to melt polycrystalline silicon materials in an inert gas (argon) environment and uses the Czochralski method to grow non-dislocated single crystals. It is mainly composed of the following systems:
Mechanical transmission system
The mechanical transmission system is the basic operating system of the single crystal furnace, which is mainly responsible for controlling the movement of crystals and crucibles, including the lifting and rotation of seed crystals and the lifting and rotation of crucibles. It can accurately adjust parameters such as the position, speed and rotation angle of crystals and crucibles to ensure the smooth progress of the crystal growth process. For example, in different crystal growth stages such as seeding, necking, shouldering, equal diameter growth and tailing, the movement of seed crystals and crucibles needs to be accurately controlled by this system to meet the process requirements of crystal growth.
Heating temperature control system
This is one of the core systems of the single crystal furnace, which is used to generate heat and accurately control the temperature in the furnace. It is mainly composed of components such as heaters, temperature sensors, and temperature controllers. The heater is usually made of materials such as high-purity graphite. After the alternating current is transformed and reduced to increase the current, the heater generates heat to melt polycrystalline materials such as polysilicon in the crucible. The temperature sensor monitors the temperature changes in the furnace in real time and transmits the temperature signal to the temperature controller. The temperature controller accurately controls the heating power according to the set temperature parameters and the feedback temperature signal, thereby maintaining the stability of the temperature in the furnace and providing a suitable temperature environment for crystal growth.
Vacuum system
The main function of the vacuum system is to create and maintain a vacuum environment in the furnace during the crystal growth process. The air and impurity gases in the furnace are extracted through vacuum pumps and other equipment to make the gas pressure in the furnace reach an extremely low level, generally below 5TOR (torr). This can prevent the silicon material from being oxidized at high temperatures and ensure the purity and quality of crystal growth. At the same time, the vacuum environment is also conducive to removing volatile impurities generated during the crystal growth process and improving the quality of the crystal.
Argon system
The argon system plays a role in protecting and regulating the pressure in the furnace in the single crystal furnace. After vacuuming, high-purity argon gas (purity must be above 6 9) is filled into the furnace. On the one hand, it can prevent outside air from entering the furnace and prevent silicon materials from being oxidized; on the other hand, the filling of argon gas can maintain the pressure in the furnace stable and provide a suitable pressure environment for crystal growth. In addition, the flow of argon gas can also take away the heat generated during the crystal growth process, playing a certain cooling role.
Water cooling system
The function of the water cooling system is to cool the various high-temperature components of the single crystal furnace to ensure the normal operation and service life of the equipment. During the operation of the single crystal furnace, the heater, crucible, electrode and other components will generate a lot of heat. If they are not cooled in time, the equipment will overheat, deform or even be damaged. The water cooling system takes away the heat of these components by circulating cooling water to keep the temperature of the equipment within a safe range. At the same time, the water cooling system can also assist in adjusting the temperature in the furnace to improve the accuracy of temperature control.
Electrical control system
The electrical control system is the “brain” of the single crystal furnace, responsible for monitoring and controlling the operation of the entire equipment. It can receive signals from various sensors, such as temperature sensors, pressure sensors, position sensors, etc., and coordinate and control the mechanical transmission system, heating temperature control system, vacuum system, argon system and water cooling system based on these signals. For example, during the crystal growth process, the electrical control system can automatically adjust the heating power according to the temperature signal fed back by the temperature sensor; according to the growth of the crystal, it can control the movement speed and rotation angle of the seed crystal and crucible. At the same time, the electrical control system also has fault diagnosis and alarm functions, which can detect abnormal conditions of the equipment in time and ensure the safe operation of the equipment.
Post time: Sep-23-2024