Fraunhofer IAF Uses AT&S Technology To Package GaN Power

Multilevel voltage converter with high-voltage GaN-on-Si technology is squeezed into 2 x 3 mm²

Fraunhofer IAF has developed a fully integrated monolithic multilevel converter in high-voltage AlGaN/GaN-on-Si technology, using AT&S’s ECP (Embedded Component Packaging) technology.

The circuit, which occupies an area of 2 x 3 mm^2,  comprises four transistors and six diodes. It is designed for maximum voltages of +/- 400 V and currents of 5 A.

With ECP technology, the power components – like the multilevel converter – are embedded into the PCB material and can be connected from both sides. The chips are connected directly via copper-plated microvias. This permits low impedance connections and significantly lower inductances compared with wirebond technology. The rear of the die is also connected by means of copper-plated microvias. This ensures excellent heat dissipation.

“We are highly impressed with the ECP technology from AT&S and see this mounting technology as opening up entirely new possibilities – particularly also for more complex monolithic integrated GaN power circuits, as used on our multilevel converter chip,” says Richard Reiner, scientist at Fraunhofer IAF. “With a conventional design, we were hardly able to use and/or evaluate the powerful chip.”

“Power electronics constitutes a major field of application and focus for the embedding technology from AT&S,” emphasised Dietmar Drofenik, CEO of the Business Unit Advanced Packaging at AT&S.

“Particularly for the use of ‘wide bandgap semiconductor’ materials, such as GaN, the embedding technology makes innovative miniaturised power packages possible for higher efficiencies, enhanced thermal performance and higher power densities. In collaboration with partners, AT&S has for example already implemented various GaN power circuits, which are characterised by excellent switching performance and high efficiency.”

AT&S and Fraunhofer IAF are presenting their power solutions at the PCIM 2017 exhibition in May in Nuremberg, Germany.