OEMs, tier-one suppliers, and market analysts agree that SiC (silicon carbide) and GaN (gallium nitride) will eventually share the market with incumbent Si technologies. However, the exact roadmap and time scale is uncertain. IDTechEx expects engineered substrates to boost overall performance, volume capabilities, and cost.
Engineered substrates could decrease the device cost of SiC MOSFETs and can increase the maximum voltage of GaN HEMTs. According to IDTechEX's analysis, vertical devices will have power density for GaN and die areas will reduce for SiC and will also increase power density. Substrates are thin discs of monocrystalline semiconductor material on which devices, such as MOSFETs and IGBTs, are grown.
75 per cent of SiC wafers are produced in the US as of 2023. With companies such as Wolfspeed and STMicroelectronics expanding into Europe and China, the emergence of other SiC wafer companies, and the transition from 150mm to 200mm substrates, the market is slated to become more competitive, driving costs down. While engineered SiC substrates show potential, it will still take a few years for them to be in mass production.
IDTechEx is aware of only one company, Odyssey Semiconductor, that produces bulk GaN substrates for GaN devices. For GaN to be used in the traction inverter, devices need to be capable of sustaining high voltages and power for extended periods, which is where current GaN technologies fall short. Alternatives for this include GaN-on-sapphire and GaN-on-SiC. GaN substrates are expensive, hence, the next best thing is to manufacture something as similar as possible to GaN, which is what engineered substrates aim to do.