Sputter Etching Effect of SiN Underlayers for Co/Pt Films.

Magneto-optical disks with Co/Pt multilayered films an RF-etched SiN underlayers were prepared. Thermomagnetic writing experiments showed that RF-etching of SIN reduces playback noise by 4 dB. We have achieved a C/N ratio of 58 dB under conditions of linear velocity. 11.3 m/s; recording frequency, 1 MHz; reading laser power, 1.2 mW; and resolution bandwidth, 30 kHz. Results of measurements of XRD and magnetic properties for Co/Pt Aims on both unetched and etched SiN suggest that noise reduction by etching of SiN underlayer comes from the better crystallographical <111> orientation perpendicular to film surface.