Major research fields
Semiconductor Physics, Nanotechnology, Crystal Growth
Our research team aims to develop a new nanoscale and intelligent methodology for compound semiconductor materials to control their self-organization processes associated with epitaxial thin film growth, bulk crystal growth, etching, and lithography. Materials dealt with include the most conventional III-V compound of GaAs for opto-electro nano-devices, as well as a strategic wide bandgap compound of SiC for high power electronics devices. In the case of GaAs, by employing a conventional molecular beam epitaxy (MBE) apparatus and a conventional electron beam (EB) direct-write lithography system, we have established a new organic-resist-free maskless EB lithography integrated with selective processes driven by MBE crystal growth/etching functionalities. In the latter case of SiC, by employing a novel high temperature and ultra high vacuum apparatus and by constructing a novel refractory furnace made of TaC, we have established a new concept of a ultra-high temperature nanotechnology to be conducted at 2000°C or higher. In the furnace, all the material transport mechanisms required for epitaxial growth and etching of SiC taking place on an atomic scale can be precisely controlled in the isothermal environment through either vapor or liquid condition. Epitaxial graphene of highest quality and large diameter on SiC is also a target.
Major relevant publications
- Ushio,S., Yoshii,A., Tamai,N., Ohtani,N., and Kaneko,T. Epitaxial graphene growth on 4H-SiC (0001) with precisely controlled step-terrace surface by high temperature annealing above 2000 ºC in UHV. Physica Status Solidi (C), 8, 580-582 (2011).
- Ushio,S., Adachi,A., Matsuda, K., Ohtani,N., and Kaneko,T. The Formation of an Epitaxial-Graphene Cap Layer for Post-Implantation High Temperature Annealing of SiC and its In Situ Removal by Si-Vapor Etching. Materials Science Forum 679-680, 777-780(2011).
- Matsuda,K.,Hirokawa,Y.,Ushio,S.,and Kaneko,T. MBE-Litho:3 nm-thick amorphous GaAs oxidized thin film functioning as highly sensitive inorganic resist for EB lithography and oxide mask for selective process. Physica Status Solidi (C), 8 ,310-312(2011).