Next-gen GaN transistors come in sight, targeting electromobility

June 20, 2014 // By Christoph Hammerschmidt
GaN transistors are regarded as the Joker in power electronics - the GaN technology promises better energy efficiency, lower switching losses and resilience even under high temperatures - ideal for deployment in automotive applications, in particular in electric ones. The Fraunhofer Institute for Applied Solid-State Technology (IAF) currently is preparing a new generation of GaN-based transistors for voltage converters. Series maturity is expected soon.

Within the scope of the ZuGaNG project, the Fraunhofer IAF scientists are digging deeply into the research GaN matter. The improved technology they are preparing promises higher switching speeds, which would translate into higher energy efficiency for the voltage converters in which they are used. Besides higher efficiency, the technology also holds out the prospect of reducing manufacturing costs significantly; the institute believes that the savings could sum up to 50%, compared to today's GaN devices.

Physical characteristics of Gallium Nitride such as high electron mobility and high critical field strength enable the design of transistors with higher durability and robustness than their conventional silicon counterparts. The high switching frequency in addition makes it possible to reduce the space requirements since the passive components can be smaller. "The miniaturisation allows us to reduce the cooling requirements and the volume which in turn translates into lower manufacturing and operating cost", explains Fraunhofer project manager Patrick Waltereit.

The research includes new concepts for semiconductor design, materials production, and process technology for the production of GaN power devices. Soon, demonstrators will be available to prove the performance of DC/DC converters utilising these next-gen GaN transistors; application fields include electromobility, battery chargers for electric cars as well as industrial manufacturing, home appliances, and photovoltaics. As one particular application in manufacturing technology, the researchers highlight generators for plasma and laser systems.

Almost ready: Demonstrator for the next generation of Gallium Nitride power semiconductors. (Source: Fraunhofer IAF)

Besides developing these demonstrators, the researchers will provide a comprehensive characterisation of GaN transistors to achieve a thorough understanding of the correlation between manufacturing parameters on one side and the structural, electrical and thermal properties of GaN devices on the other side. In addition, the technology will be optimised for reliability and robustness to qualify it for industrial deployment.

One innovative approach to reduce manufacturing costs for GaN transistors targets designs that can be executed on standard CMOS production