Semiconductor refers to a material whose conductivity is between a conductor and an insulator at room temperature. It is a material whose conductivity is controllable and ranges from an insulator to a conductor.
Refer to the following figure to make a table diagram
Second, the performance comparison of semiconductor materials
semiconductor industry chain
The rapid development of the first and second generation of semiconductor materials represented by silicon (Si) and gallium arsenide (GaAs) has promoted the rapid development of microelectronics and optoelectronics technology. However, due to the limitation of material performance, most devices made of these semiconductor materials can only work in the environment below 200℃, which cannot meet the requirements of modern electronic technology for high temperature, high frequency, high voltage and radiation resistant devices.
As a representative of the third generation of wideband gap semiconductor materials,silicon carbide (SiC) single crystal materials have the properties of large band gap width (3 times of ~Si), high thermal conductivity (3.3 times of ~Si or 10 times of GaAs), high electron saturation migration rate (2.5 times of ~Si) and high breakdown electric field (10 times of ~Si or 5 times of GaAs). SiC devices have irreplaceable advantages in the field of high temperature, high voltage, high frequency, high power electronic devices and extreme environment application fields such as aerospace, military industry and nuclear energy, making up for the defects of traditional semiconductor material devices in practical application, and are gradually becoming the mainstream of power semiconductor.
1. What is silicon carbide
Silicon carbide is a compound semiconductor material composed of silicon and carbon, which is very stable in thermal, chemical and mechanical aspects.
The different combination of C atoms and Si atoms makes SiC have a variety of lattice structures, such as 4H, 6H, 3C and so on. 4H-SiC is often used as power devices because of its high carrier mobility and high current density.
▲三种不同的 SiC 结构
2、 Development history of silicon carbide devices
SiC from the last century began to develop in the 1970s, 2001 SiC SBD commercial, 2010 SiCMOSFET commercial, SiC IGBT is still under development. With the reduction of defects and improvement of the quality of 6-inch SiC single crystal substrate and epitectic wafer, SiC device preparation can be carried out on the current 6-inch Si-based power device growth line, which will further reduce the cost of SiC materials and devices and promote the popularization of SiC devices and modules.
Development history of SiC power devices
3. Advantages of silicon carbide devices
The advantages of SiC devices over Si devices mainly come from three aspects: reducing energy loss in the process of power conversion, easier to achieve miniaturization, and more resistant to high temperature and high pressure.
Reduce energy loss. The switching loss of SiC material is very low, and the switching loss of all SiC power module is much lower than that of the same IGBT module. Moreover, the higher the switching frequency, the greater the loss difference between the IGBT module and the IGBT module, which means that for the high-speed switching work that IGBT module is not good at, All SiC power modules can not only greatly reduce losses but also achieve high speed switching.
Low resistance makes miniaturization easier。SiC material has lower on-state resistance, which can reduce the chip area at the same resistance value, and the size of SiC power module can be only about 1/10 of Si.
More resistant to high temperature. The band gap width of SiC is 3.23ev, and the corresponding intrinsic temperature can be as high as 800 degrees Celsius, which is higher than that of Si. SiC material has a thermal conductivity of 3.7W/cm/K, while silicon material has a thermal conductivity of only 1.5W/cm/K. Higher thermal conductivity can lead to a significant increase in power density, while the design of heat dissipation system is simpler, or natural cooling is directly used.
▲SiC can greatly reduce the switching loss in power conversion
4. Application of silicon carbide devices
With the development of silicon carbide manufacturing technology and the continuous decrease of manufacturing cost, silicon carbide materials have broad application and development prospects in high temperature, high frequency, optoelectronics, radiation resistance and other fields:
（With pictures of application areas)
Silicon carbide single crystal base material - ultra high purity toner
The growth of silicon carbide crystal requires high purity silicon carbide powder as raw material. The synthesis of silicon carbide raw material is the most common method of solid phase synthesis of high purity graphite powder and high purity silicon powder.
The continuous ultra-high temperature graphitization purification system independently developed by Dingli
Technology can realize the continuous production of high purity graphite with carbon content ≥99.999%. At the same time, the raw material developed for the growth of silicon carbide single crystal -- high purity toner, the highest purity can reach 99.9999%, B, Al, V and other key impurities are less than 50PPB. All indicators and sex to achieve the domestic leading level, to achieve material import substitution.