N-type silicon carbide single crystal wafer
"Silicon carbide is the world's most advanced third-generation semiconductor material. Compared with the first-generation silicon and the second-generation gallium arsenide materials, it has excellent physical characteristics such as high voltage resistance, high frequency, and high power. It is a satellite Core materials in important fields such as communications, high-voltage power transmission and transformation, rail transit, electric vehicles, communication base stations, etc., especially in aerospace, national defense and other fields, have irreplaceable advantages. "SXLK Crystal Technology Group R&D manager Ma Kangfu introduced, regarding 5G In terms of base station construction, the 5G transmission speed is fast because it has powerful 5G chips, and silicon carbide wafers are the most ideal substrate for 5G chips.
The reason why silicon carbide materials are precious is mainly related to the difficulty of development. Since 2009, SXLK is determined to break through technical problems and has invested a lot of energy in research and development. Now the purity of high-purity silicon carbide powder has reached 99.9999%, and the crystal quality is close to the international level. At the same time, the powder synthesis equipment and crystal growth furnace are also nationally produced equipment developed and produced by ourselves, which have high continuous working stability and good accuracy retention.
Silicon carbide powder with a purity of 99.9999%
The development of silicon carbide wafers, high-purity silicon carbide powder is the first step. After the powder is made, the most critical process is crystal growth. "The growth of silicon carbide crystals is different from the growth of silicon materials. It is vapor phase growth. The silicon carbide powder is subjected to a high temperature of more than 2,000 degrees Celsius in a silicon carbide single crystal growth furnace, and the growth is closed for 7 days. It grows into a diameter of 4 inches or A 6-inch round pie-shaped crystal ingot." Ma Kangfu said that during this growth process, the crystal is prone to defects. There is an indicator called a microtubule, which is only a few tenths of a thin hair The tube hole is invisible to the eyes. Once the microtubules appear, the entire crystal fails. Because the temperature is too high for manual intervention, the entire growth process is like "blindfolded embroidery", which is precisely the core technology of the chip. To solve this technical problem, they spent seven or eight years of research time. Now the crystal yield has reached 65%. Compared with the world's highest yield rate of 80%, it can be said that the SXLK technology is close to the international level.
Silicon carbide crystals grown in high temperature environments, leading the world in yield
The processing of silicon carbide wafers is also a difficult process. Ma Kangfu said that they used a lot of diamond wires with a diameter of only 0.18 mm to cut at the same time, and cut the grown crystal ingot into a piece of wafer. Each wafer is placed in the grinding equipment, the two sides are ground flat, and finally polished to obtain a wafer like a transparent glass wafer, which is a silicon carbide wafer.
High-purity semi-insulating silicon carbide single crystal wafer
In March of this year, China's largest third-generation semiconductor material silicon carbide industrial base was officially put into operation in the demonstration zone. The 300 equipment of the first phase of the project was launched at the same time, which marked the official start of the country's largest production silicon carbide industrial base.
Silicon carbide crystal growth workshop
"The 300 single crystal production equipment in the first phase of the silicon carbide industrial base has an annual production capacity of 75,000 silicon carbide single crystal substrates and annual revenues of more than 300 million yuan." SXLK project manager Zhou Liping introduced that after the project is completed, They will have an annual production capacity of 100,000 pieces of 4-6 inch N-type silicon carbide single crystal wafers and 50,000 pieces of 4-6 inch high-purity semi-insulating silicon carbide single crystal wafers. They are currently the largest silicon carbide material in China. An industrial base with an annual output value of up to 1 billion yuan. The start of this base will completely break the foreign blockade of China's silicon carbide, and realize the completely independent supply of silicon carbide.