DEPOSITION OF STRESS-FREE CO-CR ALLOY THIN-FILMS ON THIN TAPE SUBSTRATE BY KR ION SPUTTERING

Co79Cr21 and Co80Cr17Ta3 films were deposlted on the substrate of thin polyethylene napthalate (PEN) tape by using Kr and Ar ions and the facing targets sputtering (FTS) system. It is important to release the internal stress of Co-Cr films without deterioration of the crystallinity in order to avoid the curling of magnetic recording tape. Kr ions could make stable discharge at the working gas pressure as low as 10(-5) Torr because of their large ionization cross section, and suppress the recoil of Kr atoms from the target plane surface because of their large mass. Therefore, stress-free Co80Cr17Ta3 films could be deposited at low Kr pressure of 0.1 approximately 0.3 mTorr where DELTA-theta(50) of the films deposited on the PEN tape was 8-degrees. The sputtering technique by using Kr lons and the FTS system was very useful for fabricating the curl-free magnetic recording tape of well crystalline films of Co-Cr alloy such as Co79Cr21 and Co80Cr17Ta3.