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Startup company, Group4 Labs, based in Freemont, California, has signed an agreement with Alfred University (AU) researchers to develop a sacrificial substrate for diamond coatings.
S.K. Sundaram and Scott Misture, who are Inamori Professors of materials science in the Kazuo Inamori School of Engineering at AU, will oversee the project.
which is suitable for things such as high-frequency electronics.
High quality graphene manufactured at Linköping has been supplying other research teams with the material for several years. The demand is now so great that the researchers have formed a company, Graphensic AB.
Group 4 Labs’ GaN-on-Diamond substrates
Misture and Sundaram are to develop a substrate material for Group4 Lab’s novel technology which combines diamond and semiconductors to extract heat rapidly, efficiently, passively, and cost-effectively.
According to Sundaram, the micron-sized diamond coating is first applied to a sacrificial substrate. When the sacrificial substrate is removed, the diamond coating will then serve as the substrate for further processing of the semiconductor coating.
Misture and Sundaram believe that cordierite glass-ceramics are most suitable as a diamond coating substrate because the two materials are well matched with regard to thermal expansion as well as chemical and thermal stability under the processing conditions of interest to Group4Labs. The “sacrificial” substrate must also be inexpensive because it is disposed of during processing.
In the past, diamonds had been deposited on substrates with different thermal expansion coefficients, which resulted in “mismatch failure and thermal cracking,” according to Misture. The main challenge is matching the thermal expansion coefficients of the substrate and the coating. Misture and Sundaram hope to accomplish that by manipulating the glass chemistry and controlling a specific crystal phase from crystallising out.
Graphensic kicks off production
Using a novel growth method, a Swedish university spin-off has begun to grow graphene consisting of a single layer of carbon atoms, on silicon carbide. The growth method concentrates on how the heating process can control the interaction of silicon and carbon at the surface of the material
A group of researchers at Linköping University are now marketing their method of producing graphene.
There is great interest in the Nobel Prize-winning material, 88
www.compoundsemiconductor.net April/May 2012 Professor Yakimova
“As part of research, we deliver material to several projects, both in Sweden and throughout Europe. This strengthened our opinion that there is now a commercial market for our material,” says Rositza Yakimova, who leads the research group.
Graphene consists of a single layer of carbon atoms. Yakimova’s group starts with SiC, which is heated to a very high temperature. Their success lies in understanding how silicon and carbon act on the surface, and how a heating process that controls this surface can be implemented. The process is under application for a patent.
“We’ve already transferred one manufacturing technology for the material for a white LED, which is being industrialised in Japan, and now we’re initiating the industrialisation of the graphene method,” says Mikael Syväjärvi at Graphensic AB.
The hope is that Swedish graphene research and its graphene industry will get a breakthrough owing to billions in investments in Europe. However taking the step from research to commercialisation requires help.
“Alongside InnovationskontorEtt at Linköping University, we’ve developed a strategy for how to grow with the market and build our Swedish company further to deliver the material internationally. There aren’t any applications on the market yet, but the material is needed to develop them,” Yakimova adds.
Graphensic AB was established by Rositza Yakimova, Mikael Syväjärvi, and Tihomir Iakimov, and is supported by the LEAD business incubator. The company has its headquarters in Linköping in East Sweden, and uses equipment and offices at Linköping University.
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