EFFECT OF SURFACE CLEANNESS ON THE MAGNETIC-PROPERTIES OF CONICR AND COCRTA THIN-FILM MEDIA FABRICATED USING AN ULTRACLEAN SPUTTERING PROCESS

The correlation between the cleanness of the substrate surface and mag netic properties is discussed for thin-film media fabricated using an ultraclean (UC) sputtering process. Only slight dry-etching of the sub strate surface (etched depth about a few Angstrom) just before film de position results in an increase in H-c, especially in media with thin Cr and magnetic layers. The removal of the adsorbed oxygen impurities on the substrate surface by slight dry-etching in the UC process, was found to cause the increase in H-c. It is suggested that the re-adsorp tion of gas impurities makes it impossible to improve magnetic propert ies by dry-etching in the normal sputtering process. Furthermore, it i s clarified that the inducement of uniaxial magnetic anisotropy due to the texture of the substrate surface is strongly connected with the a dsorption of gas impurities on the substrate surface.