INSIDE the Laboratory & INSIDE the Common Research Facilities

Frontier Research Institute for Interdisciplinary Sciences

Advanced Interdisciplinary Research Division

Takehito Shimatsu, Professor


The author and colleagues have been conducting two research efforts based on sputter film deposition in a UHV atmosphere: development of room-temperature bonding techniques of wafers and fabrication of magnetic films for use in future high-capacity magnetic storage and memory devices.

The former study examines atomic diffusion bonding of two flat wafers with thin metal films. High surface energies of metal films and a large atomic diffusion coefficient at the grain boundaries and film surfaces enable room-temperature bonding without unusually high loading pressure. Bonding of wafers can occur with films of only a few angstroms on each side. This technique, which can bond any mirror-polished wafer, is gaining wider use for electrical and optical devices fabrication. Moreover, bonding of wafers with mirror polished metals and polymer sheets can be achieved, which extends the application of this bonding technique further.

The latter study is aimed mainly at energy-assisted magnetization switching of granular magnetic films for use for future ultra-high-density recording media for hard disk drives. We fabricated new materials. For instance, L10-type FePtRu perpendicular films show low Curie temperatures while maintaining high uniaxial magnetic anisotropy Ku. They are anticipated for use as promising materials for heat-assisted recording media. For microwave-assisted magnetization switching (MAS), we designed and fabricated a new structure for MAS characterization, and presented great reduction of switching field of granular recording media.

We are conducting collaborative studies with Japanese and overseas companies to examine practical industrial applications of these technologies.

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