Auto-Technik: So machen Siliziumkarbid-Halbleiter das Elektroauto besser

Cologne - Siliciumcarbid semiconductors are seen as a key technology for powerful yet efficient electric cars. Unlike fast computing chips, their role is to switch large amounts of electrical power with minimal losses. They are particularly important in the inverter that converts direct current from the battery to the alternating current required by the electric motor.

These inconspicuous components determine how much energy actually reaches the wheels and how much is lost as heat. Siliciumcarbid, or SiC, is a compound of silicon and carbon. While it's also used in abrasives or high-performance ceramics, it can be processed into semiconductor components much like pure silicon. Its crucial advantage is the wide bandgap.

This describes how much energy is needed to make electrons mobile and thus enable current flow. While silicon has a bandgap of about 1.1 electron volts, SiC has a bandgap of about 3.3 electron volts. This allows siliciumcarbid to withstand much higher electrical field strengths and temperatures. Consequently, SiC components can be made thinner and can handle high voltages without breaking down electrically. At the same time, SiC conducts heat better than silicon.