Research activities:

To realize the ubiquitous (or the ambient intelligence) society, in which sensors and their networks are embedded in our ambience to support our daily life through prompt warnings of various environmental crises, a marriage between non-Si technologies suitable for environmental sensing and the Si technology suitable for signal processing is indispensable. To this goal, we investigate formation of ultrathin silicon-carbide (SiC) films on Si substrates, hoping to use them as a common interface between the two technologies. We have especially succeeded in the formation of epitaxial graphene on Si substrates for the first time via graphitization of an ultrathin SiC/Si layer, thereby leading the world in this area.

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Solid-State Electronics (Prof. SUEMITSU)

SiC is a compound semiconductor that contains a pair of group-IV elements that represents conventional (Si) and bio- and nanocarbon-based (C) electronics. It also bridges the gap between Si and other II-VI or III-V compounds. SiC is a widegap semiconductor that enables high-temperature operations. High enough strength and hardness of SiC make this material suitable for use in MEMS structures. We are investigating growth of SiC ultrathin film on Si substrates, by developing a single-precursor-based gas-source molecular-beam epitaxy. The research covers from clarifying the growth kinetics to fabrication of electronic devices based on the structure.

By simply annealing the SiC/Si ultrathin film in ultrahigh vacuum, we can epitaxially grow a few layers of graphene on top of the Si substrate. Graphene is a two-dimensional honeycomb network of C atoms, in which electrons and holes can run at a speed that is ~100 times higher than that in Si. This is why graphene is called a dream material. Our research includes clarifying and controlling the surface chemistry needed to fabricate the nanostructures on Si and SiC surfaces, which are all integrated into fabrication of qualified graphene on silicon substrates. We are developing electronic devices centered on high-speed devices using this graphene-on-silicon technology.

Research topics:

1. Surface chemistry during formation of SiC films on Si substrates
2. Surface chemistry during the graphene-on-Si process
3. High-speed devices based on the graphene-on-Si structure
4. Material processing using normal-pressure plasma-enhanced chemical vapor deposition

Research Institute of Electrical Communication Tohoku University