Electricity generated from renewable energy sources often needs to be transported across long distances – for example from off-shore wind power plants to end users in the foothills of the Alps. The power electronic components currently used, however meet their limits when transferring high voltages and cause considerable energy losses. Fraunhofer IAF is therefore researching on new electronic components based on diamond: With its extraordinary physical properties, the material could soon help to establish smart-grid technologies, reducing energy losses and allowing for intelligent and flexible control of electronic networks.
Power electronic components are essential for all processes involving electric energy – the generation, the transfer or the usage of energy. They are actually part of all electronic devices, power supplies, vehicles and, not to forget, our electricity network. Here, they are necessary to control the connection of the circuits and thus to distribute energy through high-voltage transmission lines. The currently used silicon-based components are only able to operate limited voltage amplitudes and are characterized by power losses which lead to a significant temperature increase of the components. Scientists at Fraunhofer IAF therefore work on the development of the next generation of power electronic components, using diamond as a promising material.
Diamond-based power electronics reduces energy losses
An important parameter for a component’s efficiency is the material’s bandgap. With 5.47 eV, diamond presides over other materials: the combination of a large bandgap with excellent heat conductivity, high electron and hole mobility, highest breakdown field strength as well as high radiation hardness facilitates the realization of especially robust and efficient power electronic components. Diamond can be doped with boron and with phosphor, which allows the fabrication of diodes and transistor structures for applications in extreme and harsh conditions. Diamond-based power electronic components will therefore be applied where conventional materials like silicon, silicon carbide (SiC) and gallium nitride (GaN) currently fail, thus opening up new opportunities for energy transmission and distribution, with reduced energy losses and higher efficiency.
European cooperation in the project »Green Diamond«
In the recently launched research and development EU-project »Green Electronics with Diamond Power Devices (Green Diamond)«, 13 partners from all over Europe cooperate with Fraunhofer IAF in order to make diamond usable for power electronic applications. The research is funded with more than three million Euros for the next four years by the European Union. Goal of the project is the development of a MOS-FET (metal-oxide-semiconductor field-effect transistor) based on diamond, withstanding – and winning – the comparison with existing semiconductor technologies and allowing for the realization of the first power converter based on diamond. Fraunhofer IAF contributes to this development with the deposition of defect-reduced ultra-pure diamond layers, the optimization of diamond surface properties, as well as three-dimensional growth for local phosphor-doping.