C-Axis Oriented Ba-Ferrite Thin Film With Perpendicular Anisotropy Deposited on Si_(3)N_(4) Substrate

摘要

Si_(3)N_(4), a new substrate as well as thermally oxidized SiO_(2)/Si wafer substrate were used to prepare hexagonal Barium ferrite (BaM) thin films by facing target sputtering system. At substrate temperature (Ts) of 600℃, the intensities of BaM (00l) planes in X-ray diffraction diagrams were much stronger in the case of Si_(3)N_(4) substrate than that of SiO_(2)/Si wafer substrate. The value of Δθ_(50) was found about 2.28° for 25-nm thickness of BaM deposited on Si_(3)N_(4). Then, Ts was reduced to 525℃. Perpendicular coercivity (Hc_(perp)) and squareness ratio (S_(perp)) were higher in the case of Si_(3)N_(4) substrate even at 525℃. The maximum value of Hc_(perp)=3.25 kOe and S_(perp)=0.7 was found for the film of 35 nm. It was found that Si_(3)N_(4) not only reduces the Ts of BaM during in-situ deposition but also increases the perpendicular anisotropy of BaM thin film.