Power electronics is playing an increasingly important role in the generation, distribution and use of electrical energy. As a result, it makes a significant contribution to the efficiency of increasingly sustainable societies.
Power semiconductors are irreplaceable for the transition to a climate-neutral and digital society. In particular, the industrial, renewable energy and automotive sectors are currently generating increasing demand and will continue to do so in the future. All with the goal of reducing CO2 emissions, increasing system efficiency and driving digitalization. Not surprisingly, the focus is on applications such as electric cars, photovoltaics and wind turbines.
Analysts at the Yole Group expect annual growth rates of just under seven percent between 2021 and 2027. Europe is the global market leader in this segment with a thirty percent share. And companies are continuing to invest, including here in Germany. Infineon, for example, is building a 300mm Smart Power Fab for analog/mixed-signal technologies and power semiconductors at its Dresden site. Vishay Intertechnology is building a 300mm fab for automotive MOSFETs in Itzehoe. U.S. company Wolfspeed is investing 2.75 billion euros in the world's largest factory for SiC power chips in Saarland, Germany. And Bosch plans to expand its wafer fab for SiC chips in Reutlingen by another 3,000 square meters by the end of 2023.
Gallium nitride (GaN) and silicon carbide (SiC) power electronic devices are increasingly being used alongside silicon-based technologies. These wide-bandgap semiconductors enable faster and lower-loss devices for inverters with efficiencies up to 99 percent. They can switch higher voltages at higher frequencies than is possible with silicon—and with less cooling. Shorter switching times significantly reduce energy losses and allow for more compact passive components such as inductors or capacitors.
Efficiency is therefore not limited to the electrical framework, but also includes a reduction in mass and volume. For electric vehicles, this means more range per charge.
Silicon carbide and gallium nitride chips are still much more expensive than their silicon-based counterparts. This is because they are more difficult to manufacture. For example, the cost of a SiC wafer is approximately 20 times higher than that of a silicon wafer due to the much more complex and lengthy manufacturing processes. Manufacturers hope to reduce costs by using 300mm wafer technology.
In addition, SiC and GaN power electronics are still in their infancy as a pacemaker technology. Improvements in stability and reliability, especially in long-duration applications, are still under development.
Wide bandgap semiconductors are therefore not always the better solution. In addition to energy efficiency, cost, lifetime, power range and other constraints determine the design. Currently, there are four main types of power semiconductors available, in addition to hybrid technologies.