EFFECT OF SPUTTERING CONDITION ON DYNAMIC CHARACTERISTICS AND MICROSTRUCTURES OF MAGNETOOPTICAL 5.25 IN SIN TBFECO/SIN/AL DISKS FOR 532 NM RECORDING MEDIA/

A systematic study of the effect of sputtering conditions, for each la yer of the magneto-optical SiN 500 Angstrom/TbFeCo 200 Angstrom/SiN 20 0 Angstrom/Al 600 Angstrom disks, such as power and Ar gas flow rate o n the noise levels (NL) and carrier-to-noise ratio (CNR) was performed for the 532 nm high density storage media in this work. The NL droppe d to its minimum value of -71.3 dB as the sputtering power for the fir st SiN increased from 0.5 to 1.5 kW With a further increase in sputter ing power to 2.5 kW, it sharply increased to -64.5 dB. This was ascrib ed to the smooth and dense surface of the first layer at 1.5 kW as was observed in the atomic forces microscopy images. The spherical, isotr opic, fine grains with a diameter of about 0.2-0.7 mu m at 1.5 kW were found, while the longitudinal, directional granular features with a l ength of 2.5 mu m were seen at 2.5 kW. The highest CNR of 46.3 dB was observed at 0.6 kW with a constant sputtering Ar gas how rate of 25 se em for the magneto-optical layer The sputtering conditions for other l ayers are as follows: 1.5 kW with sputter Ar/N-2 gas flow rate of 30 s ccm/11 seem for the first and third SiN layer, and 0,6 kW with 25 seem of Ar for the Al reflection layer. This is due to the smooth surface morphologies of the magneto-optical layer at this optimum sputtering p ressure, as previously reported in similar research. To obtain a high readout signal, the phase compensation for the elliptic laser beam has been considered. (C) 1996 American Institute of Physics.