Quadruple-Layer Write-Once Disk for Blue Laser Based on Te–O–Pd Recording Films

Abstract

The excellent performance of a 100-GB-capacity write-once disk was demonstrated. The disk has quadruple recording layers, i.e., Layer 3, 2, 1, and 0 (from the laser-incident side of the disk) based on the 4Â Blu-ray disc (BD) format. Each layer is provided with a phase-change type memory film of Te-O-Pd, whose thickness was 20 nm for Layer 0, and only 6 nm for Layers 1, 2, and 3 in order to obtain high transmissivity. Additionally, for Layers 2 and 3, a metallic reflection layer was not needed and an AlN film with high thermal conductivity was formed next to each recording film. The AlN film suppressed the heat-induced damage of thin recording films. Consequently, the high transmissivities of 64% (Layer 1), 75% (Layer 2), and 81% (Layer 3) were achieved so that a quadruple layer disk with high quality was realized. The experimental disk showed tolerance to a wide range of writing speeds from 1Â (36 Mbps) to 4Â (144 Mbps). Good jitter values for each layer within an available maximum laser power of 27 mW on the disk were demonstrated. The acceleration test for lifetime using the Arrhenius plots showed that this write-once disk has an estimated lifetime of more than 100 years at 30 C and 85% relative humidity (RH).

Analysis of layered assays and volume microarrays in stratified media

“…For example, a four layer system based on the Blu-Ray DiskÔ format recorded 100 Gbyte on a single disk. 18 Efforts to increase storage density further have moved in the direction of shorter wavelengths and layered structures. Using optical sectioning technologies for reading and writing, 19 as many as 16 layers can be written into a 80 mm thick material using two photon methods.…”

Characterization of write-once blu-ray disk containing Cu–Al/Si recording layer using transmission electron microscopy

“…The melting point of Si is 1414°C while the Cu-Al alloy utilized in this study melts at about 1045°C. Furthermore, thermal simulation studies of optical disks [15][16][17][18] indicated the disk sample is unlikely heated over 800°C at P w = 7.9 mW for the 4ϫ recording performed in this work. Instead of melting induced by laser irradiation, the Cu-Al/Si layer should thus experience a heating process similar to the rapid thermal annealing.…”

A low-power, long-life and energy-saving method for cold data storage

“…In contrast, Blu-ray disc records the data by physical change to a recording layer medium, which is an irreversible process and almost impossible to tamper with the data.  High-durability and long-term preservation of data for more than 50 years [4]. Blu-ray disc is covered with a transparent protective layer on the recording layer, which makes it resistant to changes in the external temperature, humidity and light.…”