窒素イオン注入により作製したパタン媒体の再生信号解析によるパタン品質の評価

概要

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Patterned media were fabricated by nitrogen ion implantation and changes of the pattern quality with ion energy were evaluated by analyzing the readback signals. The ion energies were 8, 12, 14 and 16 keV, and the dosage was 2.5×1016ions/cm2. Auto correlation signal to noise ratio of DC-magnetized preamble pattern was maximized at 12 keV, though the saturation magnetization of the ion-implanted area was decreased as the ion energy increased throughout the range from 8 keV to 16 keV. 2D-maps of the signal amplitude showed larger fluctuation of the pattern shape for the ion energy of 16 keV than for the ion energy of 8 keV. The standard deviations of the pattern width were 4.3 nm and 8.4 nm for 8 keV and 16 keV, respectively, which were almost the same values as the standard deviations of calculated ion lateral distribution. The results indicate that some ions distributed under the mask by the ion lateral straggling and thus affected the pattern quality. For high quality patterning, ion lateral straggling needs to be suppressed by lowering ion energy.