| Budget Amount *help |
¥3,610,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥210,000)
Fiscal Year 2007: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
The purpose of this research is to develop a high-density, high data transfer rate optical memory which utilizes a minute aperture of around 100 nm of its typical size, scanning several ten's of nanometers above a metal patterned medium. In promoting this research, we considered the following "three conditions" were quite essential. Firstly, when demonstrating readout signals, i) the optical head (aperture) should have real spatial resolution of approximately several 10's of nanometers. Secondly, readout signal should be at real frequency band of approximately 10MHz or more, indicating high signal-to-noise ratio. Finally, the utilized optical head should be a miniaturized or compact one which could be applicable to a compact optical memory device. Final concrete destination concerning our memory device performances is to detect 70- to 80-nm-long bit patterns at frequency band of more than 10 MHz, with sufficient signal-to-noise ratio of approximately 18 dB.
In this final research period
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, signals corresponding to 150 to 50 nm long patterns were successfully confirmed, based on the results obtained in former research period. Concrete contents include (1) demonstrating the effectiveness (high spatial resolution) of a triangular aperture in combination with polarized light, (2) confirming the effectiveness of diminishing aperture-to-medium spacing when utilizing both a protruded aperture and a miniaturized slider, and finally, (3) fabrication of a metal patterned medium of its minimum line width ranging from sub-micrometer to approximately 50 nm.
Concerning item (1), we successfully detected readout signals corresponding to 50 nm single space and 150 nm line-and-space patterns with sufficient signal-to-noise ratio. Concerning item (2), we have confirmed the effectiveness of diminishing aperture-to-medium spacing utilizing a protruded aperture mounted miniaturized optical head slider. However, even attained minimum spacing of 30-40 nm made it difficult to demonstrate inherent high spatial resolution of a triangular aperture. Finally, concerning item (3), though we could have successfully fabricated line-and-space patterns down to 70 nm of its line width, patterns having narrower line width could not be realized because of the difficulties of electron beam (EB) lithography and shading layer etching process. Less
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