Akitoshi Suzuki

Deep UV Mastering Using an All-Solid-State 266 nm Laser for an over 20 GBytes/Layer Capacity Disk

The deep UV mastering process of the next generation high density disk is demonstrated for the first time using an all-solid-state continuous-wave 266 nm laser. We have developed a novel deep UV master recorder with a laser source, and achieved a density of 20 Gbytes capacity (14 Gbit/inch2) with acceptable jitter for the compact disk size.

Effect of Heat Treatment on the Coefficient βpf for the Poole-Frenkel Effect and the Conductivity in Ta2O5 Films

The change in the coefficient βpf for the Poole-Frenkel effect and the change in the conductivity in anodized Ta2O5 films by heat treatment have been observed. Untreated films (dried at room temperature) include only neutral traps, so that the film does not exhibit the Poole-Frenkel effect and has very low conductivity. When these films are heat-treated for a few minutes in oxygen or in a vacuum, donor levels are created in the films. These films increase in conductivity by about 104 times and exhibit the Poole-Frenkel effect. When the films are heat-treated for over 10 minutes in oxygen, the conductivity decreased again. In this decreasing process, the value of βpf changed from that of an anomalous Poole-Frenkel effect into the normal one. These chances may be caused by the change in the ratio Nd (donor density)/Nt (trap density) and in the energy of the donor levels.

H-infinity servo control of the slide unit for the optical disc master code cutter

H-infinity servo control was applied to the slide unit for the optical disc master code cutter. Proposed generalized system enables the shaping of the loop transfer function with four inequalities. Designed H-infinity controller achieved nanometer level trucking accuracy enough to cope with the next generation optical discs.