SCANNING NEAR-FIELD OPTICAL MICROSCOPE WITH A LASER-DIODE AND NANOMETER-SIZED BIT RECORDING

We demonstrate 80 nm diameter bit recording for the first time using a phase change recording him and a reflection scanning near-field optic al microscope with a 785 nm wavelength laser diode. The sample structu re was a 20 nm thick ZnS-SiO2 protection layer/30 nm thick Ge2Sb2Te5 r ecording film/150 nm thick ZnS-SiO2 protection layer/polycarbonate sub strate. Writing was performed with pulsed laser light of 8.4 mW for 5 ms and 0.5 ms, and 8.0 mW for 5 ms. Written bits were observed in refl ection by illuminating a small light of 0.2 mW. in this form of record ing, a formation of phase change domains of about 50 nm in diameter is expected if the surface deformation is suppressed. Our results indica te the possibility to achieve an ultra-high recording density of more than 100 Gb in(-2).