SIC power device inverter

A cruising test conducted under specific conditions by BEV using SiC semiconductor inverters demonstrated inverters with SiC power semiconductor reduce power loss less than half of ones with Si semiconductor. As a result, the energy efficiency of BEVs is improved and cruising range is extended.

Bosch offers a comprehensive silicon carbide (SiC) power semiconductor portfolio for the mobility industry, including SiC power MOSFETs and SiC power modules designed for inverters, on-board chargers, and DC/DC converters.

Especially in high-power applications in electric vehicles, SiC power electronics are gaining ground. Compared to conventional silicon-based chips, silicon carbide semiconductors provide: superior electrical conductivity, faster switching speeds, and higher overall efficiency, resulting in reduced energy loss and lower cooling requirements.

SiC devices can withstand higher breakdown voltage, have lower resistivity, and can operate at higher temperature. SiC exists in a variety of polymorphic crystalline structures called polytypes e.g., 3C-SiC, 6H-SiC, 4H-SiC. Presently 4H-SiC is generally preferred in practical power device manufacturing.

The manufacturing process for SiC power electronics is highly complex, requiring an ultra-pure environment and involving more than ten mask/structure levels with over 300 process steps. Bosch has developed an own manufacturing process for its SiC chips, for which we adapted our own trench-etch process.

Semiconductor switches for the boost converter and inverter at the higher power levels have traditionally been IGBTs, with silicon MOSFETs viable for multi-kW ratings. However, in pursuit of higher efficiency and smaller installations, wide bandgap silicon carbide (SiC) switches can be considered.