Magnetic and recording properties of monolayer and multilayer thin-film media by using composite targets

Abstract

A single chamber deposition process (N-process) to produce multilayer media was developed using a newly designed magnetron cathode. The key feature of this cathode is its use of a composite target and magnetron design which permits specific areas of the target to be independently activated. Magnetic properties, read/write performance, and media-noise of single-layer (SL) and multilayer (ML) media produced with this cathode were compared to media fabricated using a standard two chamber process (S-process). CoCrTa:SL-media sputtered using the N-process produced ∼400–600 Oe higher Hc, ∼24% lower noise, and ∼3 dB higher SNR at 136.4 KFCI recording density in comparison to SL media sputtered by S-process. X-ray diffraction analysis indicated a higher degree of in-plane c-axis orientation in N-process SL media. Sputtering the magnetic layer at elevated temperature due to zero dwell time between Cr and magnetic layer deposition and the formation of preferred in-plane orientation in the magnetic layer contributed to the increase in Hc of N-process media. ML-media fabricated by two different sputtering processes with Cr-interlayer (Cr-IL) of 5–15 Å (1-chamber and 2-chamber) showed similar noise reduction: ∼30% at 153.4 KFCI recording density. In addition, for the comparable Hc and Mrt, the ML media sputtered by N process produced lower pulse width (PW-50), better overwrite (OW), and lower bit shift (BS).