High Rate Deposition of Mn-Zn Spinel Ferrite Thin Films Using Reactive Facing-Target Sputtering

摘要

Mn-Zn spinel ferrite thin films were prepared on a Pt underlayer by reactive facing-targets sputtering to increase the deposition rate to improve the productivity. The film prepared at P_(O2) of 25 percent crystallized and possessed 4 pi M, of 3.4 kG. The discharge voltage changed with P_(O2) because of the oxidation of the target surface. The discharge voltage-current characteristics were examined to clarify the extent of oxidation of the target's. It was found that a proper discharge voltage is required to prepare Mn-Zn ferrite films. Although saturation magnetization increased with increase in substrate temperature, the surface roughness also increased. By thinning the Mn-Zn ferrite films and inserting the hyperoxidized layer that showed flat surface as the interlayer, the surface roughness of the film decreased from 4.4 nm to 2.8 nm. Saturation magnetization was improved from 3.4 kG to 4.8 kG in the same preparation condition (T_s =400 deg C, P_(O2) = 25 percent) by adjusting the inlet position of O_2 gas. By using the new method, the deposition rate increased to be 16 times that of the conventional method.