Inorganic Write-Once Disk by Complete DC Sputtering Process for Blue Laser System

Abstract

We studied an inorganic write-once disk using an objective lens with a numerical aperture of 0.85 and a 405 nm blue-violet laser diode. We confirmed that the reflectivity of the disk was controllable by adjusting the nitrogen flow rate during sputtering of a Bi–Ge nitride recording layer and disk structure. The disk that had been adjusted to high reflectivity showed a large modulated amplitude. We confirmed that complete DC sputtering process is a practicable process to make inorganic recording stacks. This means that the structure of the equipment for the production of the disks will be simple and operation of it will be easy. We made the high-reflectivity disk by the DC sputtering deposition process. The reflectivity of the disk was 34%, the modulated amplitude was 60%, and the jitter was 5.8%.