Introduction of the principle
First of all, the high-purity polysilicon raw material is put into the high-purity quartz crucible, and melted by the high temperature produced by the graphite heater; then, the melted silicon liquid is slightly cooled down, so that it produces a certain degree of subcooling, and then a single crystal of silicon fixed on the seed crystal shaft (called the seed crystal) is inserted into the melting surface, and when the seed crystal is melted and melted, the seed crystal is slowly pulled upwards, and the crystal is then pulled under the seed crystal, and then it will be pulled upwards. Crystals will grow at the lower end of the seed crystal; then, control the seed crystal growth of a section of about 100mm long, 3 ~ 5mm in diameter, for the elimination of high-temperature solution on the seed crystal of the intense thermal shock of the atomic arrangement of the dislocations produced by the process is the introduction of the crystal; followed by enlarging the diameter of the crystal to the size required by the process, generally 75 ~ 300mm, the process is known as the release of the shoulder; and then, a sudden increase in Pulling speed for the shoulder operation, so that the shoulder approximate right angle; then, into the isometric process, by controlling the thermal field temperature and crystal lifting speed, the growth of a certain diameter specifications of the size of the single-crystal column; finally, to be most of the silicon solution has been completed crystallization, and then gradually shrink the crystals and the formation of a tail-shaped cone, known as the tailing process; so that a single-crystal pulling process is basically complete, a certain degree of heat preservation after cooling Can be removed.
Straight pull method, also known as Cheklawski (J. Czochralski) method. This method was established as early as 1917 by the Czochralski a crystal growth method, with the straight pulling method of single crystal growth equipment and process is relatively simple, easy to realize automatic control, high production efficiency, easy to prepare large-diameter single crystal, easy to control the concentration of impurities in the single crystal, you can prepare low resistivity single crystal. According to statistics, the world's production of silicon monocrystals in 70% to 80% of the production of straight pull method.
At present, the status of crystal growth equipment at home and abroad are as follows:
KAYEX Corporation
Foreign to the United States, represented by KAYEX Corporation, the production of fully automated silicon monocrystalline growth furnace. KAYEX Corporation is currently the world's largest and most advanced silicon monocrystalline growth furnace manufacturers. KAYEX products entered the Chinese market in the early 1980s and have become the most used brand in the Chinese semiconductor industry. The company's silicon crystal growth furnaces are fully automated by computerized control of the entire process from vacuuming - leakage detection - melting - crystal introduction - shoulder release - iso-diameter - closing to shutdown. The integrity and uniformity of the crystal products are good, and the diameter deviation is only ±1mm within the whole length of single crystal, and the main products are CG3000, CG6000, KAYEX100PV, KAYEX120PV, KEYEX150, Vision300, and the feeding capacity is 30kg, 60kg, 100kg, 120kg, 150kg, 300kg, etc.
The whole process of growing silicon crystal is fully automated by computer.
CGS GmbH, Germany
Crystal Growing Systems (CGS) GmbH, Germany was founded in August 1999, and its predecessor was the Crystal Growing Department of Leybold, Germany. At present, its products have covered the production of 6" to 16" monocrystalline silicon rods, the equipment is mainly EKZ2700, EKZ 3500/200, EKZ 3000/300, EKZ 3000/400 type, the feeding capacity of 60kg, 150kg, 300kg, 400kg.
Crystal Growing Systems (CGS) GmbH was founded in August 1999, which was formerly known as the crystal growth department of Leybold. p>
Research Institute of Xi'an University of Science and Technology, China
China is represented by the Crystal Growth Equipment Research Institute of Xi'an University of Science and Technology, which has been producing crystal growth equipment since '61. The main products are TDR-62B, TDR-70B, TDR-80. Shangyu Jingsheng Electromechanical Engineering Co., Ltd. is a latecomer in the domestic monocrystalline silicon growth furnace industry, independently researched and developed a truly automatic control system, and its products have rapidly occupied the IC-grade silicon material industry and the high-end solar energy industry, and its main products are TDR80A-ZJS, TDR80B-ZJS, TDR80C The main products are TDR80A-ZJS, TDR80B-ZJS, TDR80C-ZJS, TDR85A-ZJS, TDR85A-ZJS, TDR95A-ZJS, and TDR112A-ZJS.
Crystal Furnace Characteristics
The chamber of the HD series of silicon monocrystalline furnaces adopts a 3-section design. The upper barrel and cover can be raised and rotated to both sides for easy charging and maintenance, etc. The upper barrel and cover can be raised and rotated to both sides for easy charging and maintenance, etc. The furnace tube lifting support adopts double column design to improve stability. The support columns are mounted on top of the furnace support platform for easy maintenance of the equipment below the platform. Furnace cylinder lifting adopts screw lifting technology, easy and clean.
The fully automatic control system adopts modular design, easy maintenance, high reliability and good anti-interference. Dual cameras collect real-time crystal diameter information. Liquid surface temperature measurement ensures the lower seed crystal temperature and repeatability. Furnace temperature or heating power control is optional to ensure temperature control accuracy. Mass flow meter precisely controls argon flow. High-precision vacuum gauge combined with motorized butterfly valve for real-time control of furnace vacuum. The upper load cell is used for the auxiliary control of the diameter of the crystal rods. The mixed use of servo motor and stepping motor can meet the torque required for rotation and realize the precise control of rotation speed. Mass flow meter for precise control of argon gas flow.
The control software of independent property right adopts Windows platform, which is convenient, simple and intuitive to operate. A variety of curve and data cross-analysis tools provide a platform for real-time process monitoring. The complete process setting interface enables the computer to automatically complete almost all the process.
The heating power supply adopts green longitudinal 12-pulse DC power supply. It is nearly 15% more energy efficient than traditional DC power supplies.
The special temperature field design increases the crystal lifting speed by 20-30%.