Gallium niride for high-efficiency voltage converters

Already today, about 40% of the energy consumed worldwide is provided in the form of electric power. This share is expected to rise to around 60% by 2040. These enormous amounts of energy must not only be generated in a resource- and environmentally-friendly manner, but also distributed and used efficiently. For this purpose, power electronic components, circuits and systems are needed to generate the appropriate voltage and frequency profile of the electric current depending on the application. The power dissipation and production costs of these components must be consistently minimized. The introduction of efficient power electronics in the fields of regenerative energy generation and automotive electronics alone can open up previously unused savings potential of 20% to 35%. Novel power transistors made of gallium nitride (GaN) enable significant improvements in fundamental electrical properties of energy-efficient voltage converters: in the specific on-resistance, in the switching frequency of the device and, as a consequence, in the energy efficiency of the voltage conversion.

Consideration of the basic physical properties provide evidence that GaN-based, compared to silicon transistors in the 100 V to 1000 V application range, can achieve a factor of 10 improvement in on-resistance. In addition to the improvement in on-resistance, GaN-based power devices also offer a significant increase in switching frequency.

Advanced simulations indicate that the next generation of GaN/Si-based transistors can realize a 33% improvement in power efficiency over state-of-the-art silicon MOSFETs. Given a radical improvement in the product of on-resistance and gate capacitance, which is an order of magnitude better than silicon solutions, GaN- based power electronics promises to revolutionize in terms of highly integrated circuits for energy-efficient voltage conversion.

To optimize the robustness and lifetime of voltage converters, especially at high operating voltages, extremely perfect AlGaN/GaN layer systems that remain insulating even at electric field strengths of 2.5 MV/cm must be explored. To achieve this, current projects are using GaN single crystals as substrate material for the AlGaN/GaN layer systems, processing them into devices and evaluating the resulting, electrical properties.