高頻鐵釔硼磁性薄膜材料的研究與開發

High Frequency Fe-Y-B Magnetic Thin Films

劉惠雯(Hui-Wen Liu)

指導教授 ： 金重勳 博士

國立清華大學/工學院/材料科學工程學系/碩士(2007年)

https://doi.org/10.6843/NTHU.2007.00338

摘要

本論文的目的為開發高頻頻段通訊用的鐵磁薄膜，成分設計為本實驗室之前所開發的Fe-Y-B系三元塊狀非晶材料，利用直流濺鍍系統以(1)Fe、Y、B三元素濺鍍薄膜、(2)經過磁場退火處理後、(3)加入第四元素濺鍍薄膜，並研究其電性、磁性質和高頻性質。
在Fe-Y-B初鍍狀態薄膜方面：Y片所占靶材Fe80B20面積為5.6 % -功率40W的薄膜，電阻率860 μΩ-cm、飽合磁化量1.01 T、矯顽場27.3 Oe、鐵磁共振頻率2.1 GHz，在非晶狀態時平行薄面的各方向皆為等向性，此初鍍狀態共振頻率就已高達2.1 GHz。Y片所占靶材Fe80B20面積為5.6 % -功率80 W的薄膜，電阻率340 μΩ-cm、飽合磁化量0.86 T、矯顽場1.5 Oe、鐵磁共振頻率1.0 GHz、低頻導磁率700以上，在非晶狀態時平行薄膜面的各方向皆為等向性，具有很好的軟磁性質且導磁率相當高。
磁場退火處理後的Fe-Y-B薄膜方面：取自Y片所占靶材Fe80B20面積為9 % -功率60W的薄膜，經過場退火300 o C -30 min處理後，產生5 nm的α-Fe奈米晶；在500 o C -30 min的高溫場退火處理，晶粒仍只有6.7 nm的大小，顯示具有極佳的熱穩定性。經過450 o C -30 min場退火後，飽合磁化量1.07 T、矯顽場66.3 Oe、鐵磁共振頻率大於3 GHz；400 o C - 2 hr場退火後，飽合磁化量1.08 T、矯顽場47 Oe、鐵磁共振頻率2.7 GHz，顯示場退火處理後，奈米晶的形成對Fe-Y-B薄膜的高頻性質提高很多。
本實驗利用價位低廉的Fe、Y、B三元素濺鍍薄膜，不但具有高電阻率，在高頻特性方面表現不錯，因而相當有潛力應用在製作高頻通訊用的鐵磁薄膜。

關鍵字

高頻 ； 磁性薄膜 ； 鐵基 ； 場退火

並列摘要

The purpose of this thesis was to develop magnetic thin films for high frequency applications. We made of Fe-Y-B bulk metallic glasses that had developed in our laboratory. The study was divided into three parts: First, the Fe-Y-B ternary system. Second, the Fe-Y-B films which were annealed under a magnetic field after sputtering. Third, Fe-Y-B-M quaternary system. Electrical, magnetic and high frequency properties of these films were evaluated.
Amorphous Fe-Y-B thin films were sputter-deposited using composite target with Y chip on a Fe80B20 target with area ratio of Y 5.6 %. The films obtained at a dc power of 40 W showed a resistivity ρ ~ 860 μΩ-cm, 4πMs ~ 1.01 T and Hc ~ 27 Oe. The film was also shown to have a high resonance frequency fr ~ 2.1 GHz. No magnetic uniaxial anisotropy was found in the as-deposited films. The thin films obtained at a dc power of 80 W showed a resistivity ρ ~ 340 μΩ-cm, 4πMs ~ 0.86 T and a low Hc ~ 1.5 Oe. The film also had a fr ~ 1.0 GHz and a very high μ’ above 700 which remain nearly constant up to ~ 0.75 GHz.
The thin films obtained at a dc power of 60 W with Y chip on a Fe80B20 target with area ratio of Y 9 % were taken to anneal under 2500 G. Nano-grained α-Fe appealed after field annealing at 300 oC for 30 min. All films demonstrated a minor crystalline growth and good thermal stability up to 500oC for 30 min. Above 300 oC, a small increase occurred in crystallite size from 5 nm up to 6.7 nm at 500 oC. The film after 450 oC field-annealing for 30 min showed good high frequency property with Ms ~ 1.07 T, Hc ~ 66.3 Oe and fr > 3 GHz. The corresponding values were Ms ~ 1.08 T, Hc ~ 47 Oe, fr ~ 2.7 GHz for film after 400 oC field-annealing for 2 hr. The appearance of nano-grained α-Fe after field-annealing is showed beneficial to promote the high frequency properties.
The quaternary films showed inferior properties. In summary the Fe-Y-B films showed high resistivity and high frequency properties, which are promising for high frequency applications.

並列關鍵字

high frequency ； magnetic thin films ； Fe-based ； fied-annealed

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