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).

The method of Kittler and Falicov for binary alloys has been extended to the case when one of the components terminates the Bethe lattice. It has been applied to hydrogenated amorphous silicon (a-Si:H) and the results compared with experimental photo-emission spectra. It is shown that complex configurations such as SiH, and SiH, are responsible for some of the experimental peaks. This theory is compared with other meanfield theories and its limitations are fully discussed.

No abstract

50GB BD-R media with Te-O-Pd recording material was estimated to have a life expectancy of over 500 years according to acceleration test under stressed conditions. This stable recording material will reduce the possibility to lose important data even in sever storage environment.

No abstract