Semiconductor Materials in High Voltage and Temperature Applications

The rapid adoption of electric vehicles (EVs) is accelerating the shift from 400 V to 800 V battery systems, which reduce power losses and enable faster charging. This transition requires advanced semiconductors capable of operating under higher voltage and temperature conditions. This paper examines the limitations of silicon (Si), the dominant but increasingly inadequate semiconductor, and evaluates alternatives including silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and diamond. Key performance parameters such as breakdown field, bandgap, bond strength, electron mobility, carrier concentration, thermal conductivity, and cost are compared to determine their suitability for demanding applications. Silicon remains cost effective for low demand uses, while silicon carbide provides the most balanced performance by combining high efficiency with moderate cost. Gallium oxide and diamond show exceptional performance in extreme voltage and temperature environments, although their adoption is constrained by high cost. Industry practice highlights these benefits, as silicon carbide based on board chargers already achieve about five percent higher efficiency and ten times greater power density than silicon counterparts, resulting in savings in weight, space, and cost. However, challenges in manufacturing, including defect density and doping control, as well as issues in operational reliability such as threshold voltage drift and reduced breakdown voltage, continue to limit large scale commercialization.