Readout Durability Improvement of Super-Resolution Near-Field Structure Discs with PtOx–SiO2 Recording and GeNy Interfacial Layers

Two dielectric materials were added to a super-resolution near-field optical disc structure (super-RENS) to improve the readout durability. PtO x –SiO 2 (Pt 8.4 Si 21.1 O 70.5 ) layers showed O 2 desorption for temperatures above 200 °C and were usable as write-once recording layers. The GeN y interfacial layers located between the Sb 75 Te 25 and (ZnS) 85 (SiO 2 ) 15 layers suppressed degradation in the reflected light intensity from the disc, i.e., maintained the recorded structure as is, to at least 5×10 4 readout cycles using a recorded pattern designed to accelerate disc deterioration. The carrier-to-noise ratio (CNR) obtained for 100-nm marks (laser wavelength: 405 nm, numerical aperture: 0.65) was about 43 dB. It was possible to readout 2.6×10 5 cycles before the CNR decreased by 3 dB. This represents an improvement of a factor of 70 over the readout durability of a conventional super-RENS structure.