1. What is silicon carbide (SiC)?
Silicon carbide is a third-generation semiconductor material. Compared with conventional silicon, SiC offers significant advantages: it overcomes some limitations of silicon and demonstrates better power efficiency, making it a promising material for power electronics. Consequently, an increasing number of semiconductor companies have entered the SiC market.
SiC, together with gallium nitride (GaN), aluminum nitride (ALN), gallium oxide (Ga2O3) and similar materials, are classified as wide-bandgap semiconductors because their bandgaps exceed 2.2 eV; these are also referred to as third-generation semiconductors in the Chinese market.
2. Discovery and early history of SiC
SiC was first identified in 1891 when Edward Goodrich Acheson produced a carbon compound while synthesizing artificial diamond electrically. Subsequent research clarified SiC’s properties and led to various crystal growth techniques; industrial research on SiC spanned more than 70 years.
In 2001 Infineon produced one of the first SiC diodes; Cree, ROHM, ST and other companies followed with SiC diodes, transistors, and MOSFETs. Some research groups explored SiC IGBT structures, but practical applications for SiC IGBTs were limited.
Early challenges included immature crystal growth technology, a high density of crystal defects that harmed yield and reliability, and difficulty finding commercially viable applications because SiC devices were expensive. The automotive industry accelerated adoption: Tesla was one of the first automakers to replace silicon with SiC and applied it to the Model 3. Other automakers followed, accelerating large-scale in-vehicle adoption. The industry often regards 2019 as the start of rapid SiC development.
3. SiC within semiconductor material generations
Semiconductor materials are often classified by generation:
- First-generation elemental semiconductors: silicon (Si) and germanium (Ge).
- Second-generation compound semiconductors: gallium arsenide (GaAs), indium phosphide (InP).
- Third-generation wide-bandgap materials: silicon carbide (SiC), gallium nitride (GaN), aluminum nitride (ALN), gallium oxide (Ga2O3).
The bandgap reflects how strongly valence electrons are bound, i.e., the minimum energy needed for intrinsic excitation. Free electrons must gain this energy to jump to the conduction band; that minimum energy is the bandgap.
Bandgap size directly influences a device's breakdown voltage and maximum operating temperature. Materials with larger bandgaps are better suited for high-temperature and high-voltage applications.
Silicon has a bandgap of about 1.12 eV. SiC’s bandgap is roughly three times larger, so for the same voltage rating an SiC device can be much smaller than a silicon device—typically around one tenth the area. The higher the voltage, the more pronounced the area advantage; or conversely, for the same die area, SiC provides much higher voltage tolerance.
Key advantages of SiC
- High breakdown field: The critical breakdown field can reach up to 2 MV/cm (4H-SiC), providing much higher voltage capability, roughly an order of magnitude greater than silicon.
- Better heat dissipation: SiC has higher thermal conductivity (about three times that of silicon), improving heat removal and enabling devices to operate at higher ambient temperatures. Theoretically, SiC power devices can operate at junction temperatures up to 175°C, allowing for significantly smaller heatsinks.
- Low conduction and switching losses: SiC has about twice the electron saturation velocity of silicon, enabling very low on-resistance (orders of magnitude lower than silicon in some cases) and low conduction losses. Its larger bandgap reduces leakage currents by several orders of magnitude. SiC devices also lack the current tail during turn-off seen in silicon IGBTs, yielding lower switching losses and enabling much higher switching frequencies (potentially an order of magnitude higher than silicon).
- Smaller power module volume: Higher device current density (for example, some Infineon SiC products report up to 700 A/cm) allows all-SiC power modules (SiC MOSFETs and SiC SBDs) to have significantly smaller package sizes than silicon IGBT power modules at the same power level.
Main drawbacks
One notable drawback of Schottky diodes is relatively large reverse current due to the metal-semiconductor junction. Under reverse bias, they are more prone to leakage current. Schottky diodes also tend to have lower maximum reverse voltage ratings; common maximum values are often 50 V or lower. Reverse voltage refers to the voltage at which the diode breaks down under reverse bias and begins to conduct significant current. Before reaching the maximum reverse rating, a Schottky diode will still leak a small amount of current. Depending on the application, this leakage behavior may or may not be acceptable.
SiC market outlook
Market research estimated that the SiC power device market exceeded $1 billion in 2021 and is projected to surpass $3.7 billion by 2025, with a compound annual growth rate above 34%.
Another research firm projected the compound semiconductor power device market to grow from $980 million in 2021 to $4.71 billion in 2025, with SiC taking the majority share; this firm estimated SiC’s 2025 market at about $3.4 billion.
In applications, new-energy vehicles are the primary driver: in 2021 vehicle procurement accounted for about two-thirds of total SiC demand, and that proportion is projected to rise to around 76% by 2025.
The global IGBT market is roughly $8–11 billion per year. If SiC device costs fall to about $750, capturing 30% of incremental market growth would represent more than $3 billion. If costs fall further to about $550, capturing at least 50% of the existing market could exceed $5 billion. SiC is expected to progressively displace silicon IGBT/MOSFET devices down to lower power levels, potentially achieving a multibillion-dollar market.
Survey of SiC companies in China
SiC substrate companies in China include Tianyue, Tianke, Tongguang Crystal, China Electronics 2nd Research Institute, Sanan, Shenzhou Technology, Century Jingguang, Chaoxinxing, Zhongke Gangyan, Luxiao, Tony, Jingsheng Mechatronics, Zhejiang Jingrui, Dahe Thermal Magnetic, and others preparing to enter the sector.
Epitaxy is mainly performed by Hantian Tiancheng and Tianyu; Tianke and Tianyue also have some epitaxy capability, along with Guosheng and Puxing affiliated with CETC.
Device manufacturers include CR Micro, Silan Micro, Zhanxin, Century Jingguang, Taike Tianrun, Basic Semiconductor, Sanan, Jita, Qidi (Changguang), Yangjie Technology, CRRC Times, Xinguang Runze, and others.
