One-Head Near-Field Writing/Erasing on a Rewritable Dual-Layer Optical Disk Having High-Index Cover and Separation Layers

A low specific on-resistance (R S,on ) silicon-on-insulator (SOI) trench MOSFET (metal-oxide-semiconductor-fieldeffect-transistor) with a reduced cell pitch is proposed. The lateral MOSFET features multiple trenches: two oxide trenches in the drift region and a trench gate extended to the buried oxide (BOX) (SOI MT MOSFET). Firstly, the oxide trenches increase the average electric field strength along the x direction due to lower permittivity of oxide compared with that of Si; secondly, the oxide trenches cause multiple-directional depletion, which improves the electric field distribution and enhances the reduced surface field (RESURF) effect in the SOI layer. Both of them result in a high breakdown voltage (BV). Thirdly, the oxide trenches cause the drift region to be folded in the vertical direction, leading to a shortened cell pitch and a reduced R S,on . Fourthly, the trench gate extended to the BOX further reduces R S,on , owing to the electron accumulation layer. The BV of the MT MOSFET increases from 309 V for a conventional SOI lateral double diffused metal-oxide semiconductor (LDMOS) to 632 V at the same half cell pitch of 21.5 µm, and R S,on decreases from 419 mΩ · cm 2 to 36.6 mΩ · cm 2 . The proposed structure can also help to dramatically reduce the cell pitch at the same breakdown voltage.

Section: Introductionmentioning

confidence: 99%

New Wobble-Address Format for an Optical Disc with a Separated Guide Layer

Ogawa

Usui

Okano

et al. 2013

“…A near-field optical recording (NFR) system using a solid immersion lens (SIL) 1) has a fourfold higher recording density than the Blu-ray disc system. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Some studies have shown the realization of a large recording capacity using multilayer recording techniques for optical disks, [17][18][19][20][21] but the data transfer rate is limited. The NFR system is expected to realize not only a large capacity but also a high data transfer rate because its numerical aperture (NA) is more than two times higher and the optical beam spot can be less than half the diameter of current Blu-ray optical systems.…”

Section: Introductionmentioning

confidence: 99%

Near-Field Optical Recording Using Solid Immersion Lens for High-Density Flexible Optical Disks

Koide

Kajiyama

Sato

et al. 2013

We propose a near-field optical recording flexible optical disk (NFR-FOD) for high-density recording at a high data transfer rate. We built a prototype high-density NFR-FOD that had a track pitch of 0.16 µm and we stacked some recording layers on a thin substrate that was 0.1 mm thick. We rotated the NFR-FOD closing the mechanical stabilizer on a drive system with less than 10 µmp–p axial run-out and achieved precise gap servo operation at a high rotational speed. We demonstrated near-field optical recording with a solid immersion lens with a numerical aperture (NA) of 1.84 on the NFR-FOD. The NFR-FOD has a fourfold higher recording density than the current Blu-ray disc, corresponding to a capacity of 100 Gbytes per layer, and a high data transfer rate of 250 Mbps, while rotating at half the speed.

“…The NFR system has more than four times higher recording density than the Blu-ray disc system. [2][3][4][5][6][7][8][9][10][11][12][13][14] Multilayer recording techniques for optical disks 15,16) is effective for realizing a large capacity, but the data transfer rate is limited as the mark size, which is caused by the numerical aperture (NA) of the 0.85-Blu-ray disc system. NFR techniques using SIL have more than two times higher NA than Blu-ray disc and have the feasibility of achieving more than two times higher data transfer rate recording at the same disk rotational speed; however, the feasibility of high-data-transfer-rate recording of more than 200 Mbps using NFR techniques with narrow-track pitch disks has not yet been reported.…”

Section: Introductionmentioning

confidence: 99%

High-Speed and Precise Gap Servo System for Near-Field Optical Recording

Koide¹,

Kajiyama²,

Tokumaru³

et al. 2012

We propose a high-speed and precise gap servo control system that is based on the feed-forward control method that can reduce the harmonic disturbance (RHD-FFC) on a near-field optical recording system with a solid immersion lens. An optical disk of 1.2 mm thickness rotates with about 30 µmp–p of axial run-out. The axial run-out prevents a gap servo from performing precisely at high rotational speed. The RHD-FFC method can suppress harmonic disturbances of gap error signal and can perform at high speed while keeping less than 25 nm of gap length between an optical head and a rotational disk surface. We confirmed that the gap servo applying the RHD-FFC method performed precisely and achieved at high disk rotational speed of 11000 rpm with a 1.2-mm-thick optical disk with a track pitch of 0.16 µm, corresponding to a data capacity of 100 Gbyte.