China has successfully developed 6-inch silicon carbide wafers with an annual output of 70,000 pieces

2021-03-24 08:09:27

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Summary of information:

From 2 inches, 3 inches, 4 inches to today's 6 inches of silicon carbide single crystal substrate, Chen Xiaolong team spent more than 10 years to take the lead in realizing the independent research and development and industrialization of silicon carbide single crystal substrate in China. According to the "Chinese Science Journal" reported on the 12th, not long ago, the research team of Chen Xiaolong, a researcher at the Institute of Physics of the Chinese Academy of Sciences, cooperated with Beijing Tianke Heda Blue Ray Semiconductor Co., LTD. (hereinafter referred to as Tianke Heda) to solve the 6-inch diameter expansion technology and chip processing technology, and successfully developed a 6-inch silicon carbide single crystal substrate. As of March 2014, Tianke Heda has formed a production line with an annual output of 70,000 silicon carbide wafers.

As a third-generation semiconductor material, silicon carbide can be used to make a new generation of energy-efficient power electronic devices, and is widely used in various fields of the national economy, such as air conditioning, photovoltaic power generation, wind power generation, high-efficiency motors, hybrid and pure electric vehicles, high-speed trains, smart grids, ultra-high voltage power transmission and transformation. Compared with the use of traditional silicon devices, the use of silicon carbide semiconductor power electronic devices can greatly reduce the energy loss of the power system, improve the efficiency of power use, reduce the size of the power system, and improve the reliability of the system operation and reduce the cost of the system. The popularization and application of high-efficiency and energy-saving silicon carbide power electronic devices can provide technical support for industrial upgrading, energy saving and emission reduction and the construction of a low-carbon society.

According to reports, the United States F-22 fighter jet also uses a large number of silicon carbide semiconductor devices. China's silicon carbide technology was also used in the military earlier, and is now slowly expanding to civilian aspects, once popularized, it will create huge social benefits.

Chen Xiaolong, a researcher at the Institute of Physics, Chinese Academy of Sciences

6-inch silicon carbide crystal and single crystal substrate sheet

Third generation semiconductor materials

Researchers told reporters that in the 1950s and 1960s, silicon and germanium formed the di generation of semiconductor materials, which were mainly used in low-voltage, low-frequency, medium-power transistors and photodetectors. Compared with germanium semiconductor devices, silicon semiconductor devices have better high temperature resistance and radiation resistance.

By the late 1960s, more than 95% of semiconductors and 99% of integrated circuits were made of silicon semiconductor materials. Until now, most of the semiconductor products we used were based on silicon materials.

After entering the 1990s, gallium arsenide and indium phosphide represent the second generation of semiconductor materials, which can be used to make high-speed, high-frequency, high-power and light-emitting electronic devices. Due to the rise of information superhighway and the Internet, second-generation semiconductor materials are widely used in satellite communication, mobile communication, optical communication and GPS navigation.

Compared with the previous two generations of semiconductor materials, the third generation of semiconductor materials are often referred to as wide gap semiconductor materials or high temperature semiconductor materials. Among them, silicon carbide and gallium nitride are representatives of mature development in the third generation semiconductor materials.

The reporter learned that silicon carbide single crystal is a wide band gap semiconductor material, with large band gap width, strong critical breakdown field, high thermal conductivity, high saturation drift speed and many characteristics, is widely used in the production of high temperature, high frequency and high power electronic devices.

On gallium nitride, it has been reported that a 2-inch gallium nitride chip can produce 10,000 high-brightness LED lights with 10 times the brightness of energy-saving lamps, 3 to 4 times the luminous efficiency of energy-saving lamps, and 10 times the life of energy-saving lamps. You can also make 5,000 blue lasers with an average price of about $100; It can also be used in power electronic devices to reduce system energy consumption by more than 30%.

Because of the small lattice mismatch between silicon carbide and gallium nitride, silicon carbide single crystal is the ideal substrate material for gallium nitride based LED, Schottky diode, gold oxide half-effect transistor and other devices. Chen Xiaolong Research Group (Functional Crystal Research and Application Center) of Advanced Materials and Structure Analysis Laboratory of the Institute of Physics has been engaged in the research of silicon carbide single crystal growth for a long time.

The United States is far ahead in silicon carbide chip technology, which is widely used in advanced weapons such as the F-22. (Data map)

The breakout of large-size chips

Although the ideal substrate for gallium nitride growth is gallium nitride single crystal material, this material can not only greatly improve the crystal quality of epitaxial film, reduce the dislocation density, but also improve the device service life, working current density and luminous efficiency. However, the preparation of gallium nitride bulk single crystal materials is very difficult, so far there is no effective method.

To this end, researchers grow thick GAN films on other substrates (such as silicon carbide), and then separate the substrate and GAN thick film by stripping technology, and the separated GAN thick film can be used as the epitaxy substrate. Although the epitaxy of gallium nitride thick film as substrate, compared with the epitaxy of gallium nitride thin film on silicon carbide material, the bit error density is significantly lower, but it is expensive.

Therefore, Chen Xiaolong's team chose silicon carbide single crystal substrate research. He pointed out that silicon carbide single crystal substrate has many outstanding advantages, such as good chemical stability, good electrical conductivity, good thermal conductivity, does not absorb visible light, but also has shortcomings, such as high price.

In the early years, the price of silicon carbide wafers on the global market is very expensive, and the international market price of a 2-inch silicon carbide wafers has been as high as $500 (2006), but it is still in short supply. High raw material costs account for more than 10% of the price of silicon carbide semiconductor devices, "silicon carbide chip prices have become the bottleneck of the development of the third-generation semiconductor industry." Chen Xiaolong said.

In order to reduce device costs, the downstream industry has put forward large size requirements for silicon carbide single crystal substrates. Therefore, the use of advanced silicon carbide crystal growth technology to achieve large-scale production and reduce the production cost of silicon carbide wafers will promote the rapid development of the third-generation semiconductor industry and expand market demand.

Tianke Heda was founded in 2006, based on the research results of Chen Xiaolong's research team in the field of silicon carbide. Since its establishment, Tianke Heda has developed silicon carbide crystal growth furnace and silicon carbide crystal growth, processing technology and professional equipment, and established a complete silicon carbide wafer production line.

Over the years, Tianke Heda is committed to improving the quality of silicon carbide crystals, as well as the research and development of large-size silicon carbide crystals, the industrialization of advanced silicon carbide crystal growth and processing technology, large-scale production and sales of silicon carbide wafers with independent intellectual property rights.

10 years of independent innovation

As a silicon carbide substrate provider, the United States Cree Company has monopolized the international market for a long time. Cree released a 6-inch silicon carbide crystal in 2011, the same year that Tianke Heda began mass production of 4-inch silicon carbide crystals.

In 2013, Chen Xiaolong's team began to research and development of 6-inch silicon carbide crystals, and it took nearly a year to develop the domestic 6-inch silicon carbide single crystal substrate developed by the team. The test proves that the crystal quality of domestic 6-inch silicon carbide crystal is very good, which marks that the research and development of silicon carbide single crystal growth of the physics Institute has reached the international advanced level, and can provide a material basis for the localization of high-performance silicon carbide electronic devices.

"Although we started a little late, through more than 10 years of independent research and development, the technological gap between us and foreign countries is gradually narrowing." Chen Xiaolong said. As a pioneer in the production and manufacture of domestic silicon carbide wafers, Tianke Heda has broken the foreign monopoly and filled the domestic gap, and the silicon carbide wafers produced are not only mature technology, but also lower than the price of similar international products.

As of March 2014, Tianke Heda has formed a production line with an annual output of 70,000 silicon carbide wafers, which has promoted the sustainable and stable development of China's third-generation semiconductor industry and achieved better economic and social benefits.

Chen Xiaolong pointed out that the current silicon carbide is mainly used in three major areas: high-brightness LED, power electronics and advanced radar, and may enter the home market in the future, which means that the independent innovation and industrialization of Chen Xiaolong team will continue.