TILT-TARGET MAGNETRON SPUTTER FOR DEPOSITION OF MAGNETOOPTICAL DISK

A 3.5-inch magnetooptical disk is made by tilting the TbFeCo target in a DC circular magnetron sputtering process. The composition of the re cording layer is controlled by using the Tb-rich deposition area. The optimal tilt angle of our target for uniform radial composition distri bution on the disk is found to be about 15-degrees. A model was propos ed to explain the observed Tb, Fe and Co content variation with the ti lt angle of the target. The dynamic read/write test also showed that g ood carrier to noise ratio (CNR) was obtained at this angle. A new dep osition process for magnetooptical (M-O) disk based on the tilt target method is proposed; it has the merits of enabling simultaneous deposi tion of multiple disks. The CNR of the disk made at 15-degrees tilt an gle is 53 dB.