Associate Professor Francesca Iacopi and her team from Griffith University have joined stellar company in Washington DC as 2014 winners of a TechConnect World Global Innovation Award for their discovery of new processes and material systems supporting the practical fabrication of graphene microstructures on silicon carbide (SiC). These global awards are presented to the top technologies ranked for the likely positive impact on their industry sectors, and are designed to assist in accelerating international exposure to potential commercialisation partners.
Graphene has extraordinary material properties for electronic and electromechanical micro-devices; however, most graphene synthesis methods are not compatible with the manufacture of complex devices. The new process developed by the Griffith team, which synthesises graphene from SiC on Si wafers, is an exciting breakthrough because it provides opportunities for realistic mass production. At high temperatures we know that Si atoms can be evaporated from the top surface of crystalline SiC wafers, leaving behind carbon in a graphitic form through a process called sublimation.
Associate Professor Francesca Iacopi’s team has instead used a lower temperature, catalytic approach to obtain graphene from epitaxial SiC films on Si wafers, thus enabling a substantially cheaper way to obtain high-quality patterned graphene at the wafer-level. Industry standard Si wafers are used in the place of extremely expensive SiC wafers. Furthermore, the SiC on Si can easily be machined through conventional micromachining processes.
ANFF-Q commissioned an Australian-first SiC epitaxial reactor. The MkII, a custom-designed and built system was jointly developed with global volume semiconductor industry equipment manufacturer SPTS Technologies. This new system can handle industrial scale 300 mm wafers in batch quantities to potentially deliver self-aligned high quality graphene, in a transfer-free, low-temperature process, directly onto complex patterns of SiC over large areas. The combination of a crystalline SiC core with a surface graphene coating is ideal for sensing devices. The already exceptional mechanical properties of SiC (which is the second hardest material after diamond) can be further enhanced by graphene, resulting in extraordinary fracture strength.
The applications for this breakthrough are numerous and already the team have produced SiC micro-resonators by replacing the traditional metal layers with a molecule-thick, transparent, highly conductive graphene layer. The graphene, less than a nanometre thick, is as conductive as gold. Additionally, graphene offers a wealth of surface chemistry approaches for targeting specific ions and molecules. The research targets devices such as extraordinarily sensitive and versatile chemical micro-sensors that have applications ranging from health to environmental monitoring.
Associate Professor Francesca Iacopi, an ARC Future Fellow, believes that: “In the next decade silicon carbide, and other wide band gap materials, will unlock technology behind a vast range of energy-efficient smart devices. These devices will increase the efficiency of photovoltaic panels, hybrid/electric cars, high-power industrial drives, motor drives, smart grids and power utilities, improving energy efficiency and lessening our carbon footprint. There’s also potential for accelerometers and gyroscopes for aerospace and automotive applications, as well as in the harsh environments of mining and deep sea exploration.”