All power semiconductors used in electric cars to date are based on pure silicon. This has many advantages. For example, the same processes can be used to manufacture the silicon crystals, and for their further processing, as for computer chips. However, as the voltage increases – keyword 800 volts – the semiconductors become larger and larger, while at the same time their efficiency decreases during driving.
Therefore, ZF is using a new technology for the first time: Instead of silicon transistors, components made of silicon carbide are used in power electronics. In this material, each silicon atom is bonded to four carbon atoms and vice versa. Carbon atoms are not only smaller than their silicon counterparts, but also bind the free electrons more tightly to themselves. This allows the same voltage to be processed with chips that are ten times thinner. The semiconductors of an 800-volt drive
are only about 100 micrometers thick and offer significantly lower internal resistance.