Write-Once Medium with Fe-Doped BiO_x Thin Films for Blue Laser Recording

Fe:BiO_x films are fabricated on K9 glass substrates by rf-magnetron sputtering of a BiFeO target under argon atmosphere with increasing sputtering power from 80 to 200W at room temperature. It is found that the thin films grown at the sputtering power of 160W can be formed at an appropriate deposition rate and have an improved surface morphology. The XPS result reveals that the films investigated are comprised of Bi, Fe and O elements. A typical XRD pattern shows that no phase transition occurs in the films up to 400°C. The results of the blue laser recording test demonstrate that the Fe:BiO_x films have good writing sensitivity for blue laser beam (406.7nm) and good stability after reading 10000 times. The recording marks of 200nm or less are obtained. These results indicate that the introduction of Fe into BiO_x films can reduce the mark size and improve the stability of the films.