New materials for sustainable transportation systems

AT&S is a leader in the development of new technologies for the production of state-of-the-art microelectronic systems. For the EU project HiEfficient, which was successfully completed last year, AT&S investigated the potential of alternative semiconductor materials such as gallium nitride and silicon carbide for green and efficient transportation systems. With 33 partners from industry and research, AT&S has developed semiconductor modules for onboard chargers and inverters for electric cars that are significantly lighter, more robust and more efficient than anything currently available on the market.

Semiconductor materials such as silicon play a crucial role in modern economies, and not just as the raw materials for modern microchips. They have also become indispensable wherever circuits need to be switched quickly and reliably. Modern semiconductor-based inverters, for example, make it possible to convert the direct current from batteries into the alternating current that is required for electrical and electronic systems. In the EU research project HiEfficient, engineers from AT&S, in cooperation with colleagues from the company AVL and research institutes, have developed an inverter that can be made significantly smaller and lighter than the silicon-based versions used today by using the semiconductor material gallium nitride.

“Technical innovations are and will remain the basis of AT&S’s success, and strong European partnerships such as HiEfficient make it possible to develop sustainable solutions for the major challenges of the future. The efficient use of electricity is the basic prerequisite for the green technological revolution that will make our transportation, communication and energy systems fit for the future. Our HiEfficient inverter is impressive proof of how much we can contribute with our expertise. Our R&D team has done a really great job,” says AT&S R&D Program Manager Mike Morianz.

Lighter, smaller, cooler

The inverter that AT&S helped develop for the EU-funded HiEfficient project is ten percent smaller and lighter than conventional systems. Moreover, the electrical and thermal losses are significantly lower, allowing car manufacturers to save costs at system level, improve battery performance and significantly increase the range. The efficiency of the new inverters is over 98 percent and the reduced thermal load increases the reliability of the technology, which enables car owners to enjoy carefree driving for a long time.

AT&S’s contribution to the inverter consists of a so-called “half bridge”, which forms the heart of the module with two embedded semiconductor switches. The gallium nitride switches enable efficient operation at higher frequencies with lower losses and AT&S’s sophisticated embedding technology allows much smaller form factors. The switches made of gallium nitride achieve a switching frequency ten times higher than silicon variants and, thanks to AT&S know-how, can be accommodated in tiny modules that take up 70 percent less space. To achieve these excellent values, AT&S has not only used the latest embedding technology, but has also developed a completely new copper sintering process for high-voltage components that can withstand high voltages and currents.

The results of the research team from AT&S and AVL will soon be published in a scientific publication, which has been nominated for the “Best Paper Award PCIM 2025”.