15 November 2011

EU-funded HiPoSwitch project launched, targeting more efficient power electronics

With a budget of €5.57m (including nearly €3.58m of funding from the European Union), the three-year project HiPoSwitch (‘High Power Switch’) has been launched (lasting from September 2011 to end-August 2014). The aim is to develop more compact and powerful energy converters, e.g. for use in information and communication technology and solar inverter technology, transforming continuous and alternating current into the effective voltages used by systems.

Low energy consumption and high output power are the core requirements for modern power converter systems, which need to preserve natural resources and cope with the increasing power consumption in communication infrastructure required for further increased data rates. Project activities cover the whole value-added chain, ranging from the development of power devices based on gallium nitride (GaN) transistors to their industrial applications.

HiPoSwitch focuses on GaN-based transistors as the key switching devices promising increased efficiency in future power converter systems, as well as smaller volume and weight along with enhanced performance. The efficiency of existing systems is largely limited by the active components that are used. These are mostly based on silicon, and are therefore reaching material-related limits. Alternatively, silicon carbide (SiC) is rather expensive, inhibiting widespread applications.

In contrast, due to the much lower on-state resistance of GaN power transistors, combined with much reduced input and output capacitances, GaN can form the basis of power switches operating at much higher frequencies without suffering from major switching losses. The increase in switching frequency also means that the volume of passive components such as inductors, current transformers and capacitors can be significantly reduced. So, the whole assembly can be smaller and lighter.

For HiPoSwitch, the GaN transistors will be fabricated on cost-efficient silicon substrates, making them more attractive economically. Long term, they should combine much improved technical properties with comparatively low cost.

Coordinated by Berlin-based Ferdinand-Braun-Institut, Leibniz-Institut fur Hoechstfrequenztechnik (FBH), eight European project partners provide complementary competencies covering the complete value-added chain, from R&D (FBH; the Slovak Academy of Sciences, Institute of Electrical Engineering; Vienna University of Technology in Austria; and Italy’s University of Padua) to industrial application (German deposition equipment maker Aixtron SE, Artesyn Austria GmbH & Co KG, Belgian epiwafer supplier EpiGaN, and Infineon Technologies Austria AG).

Throughout the project, normally-off GaN power transistors in vertical device architecture will be jointly developed by FBH and Infineon Technologies Austria. Processing will be carried out mainly on GaN-on-Si wafers provided by Imec spin-off EpiGaN but also benchmarked against GaN-on-SiC epitaxial wafers delivered by FBH. The work aims to rapidly transfer the process modules from FBH to the high-volume process line at Infineon. Exploratory concepts towards novel normally-off power transistors and devices operating at high temperatures up to 250°C, for example, will also be investigated, predominantly at the Technical University Vienna and the Slovak Academy of Sciences in Bratislava. Hence, the basis for further technological improvements in the future will be established during the project. All device developments will be supported continuously by intensive reliability testing and failure mode investigations. For this, the University of Padua in particular will contribute its comprehensive experience in GaN device reliability and failure mechanisms.

In parallel to device development, the industrial partners will concentrate on transferring the technology that is developed to a high-volume production environment: EpiGaN is focusing on 200mm GaN-on-Si epitaxy developments, while Aixtron will establish the prerequisites for high-volume epitaxy by optimizing the corresponding growth reactors. Infineon Technologies Austria AG will evaluate the transistor concepts and the GaN-on-Si epiwafers from EpiGaN in their process line. Finally, Artesyn Austria will demonstrate the capability of the technology by building a highly efficient kilowatt-class inverter system, to be implemented, for example, in new-generation base-stations for mobile communications.

The aim is that, after project completion, GaN power transistors and 200mm GaN-on-silicon substrates will be commercially available and marketed worldwide.

Tags: GaN power transistors EpiGaN

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