巨磁阻讀取磁頭元件之奈米分析

Nanoanalyses of GMR Read Head Device

黃榮潭(R. T. Huang) ； 江正誠(C. C. Chiang) ； 林智仁(C. J. Lin) ； 陳福榮(F. R. Chen) ； 開執中(J. J. Kai)

《材料科學與工程》 35卷4期 (2003/12) Pp. 199-206

https://doi.org/10.6409/JMSE.200312.0199

摘要

Cap/NiFe/CoFe/Cu/CoFe/Ru/CoFe/NiFe/NiMn/seed layer自旋閥讀取磁頭在熱應力測試200℃，1000小時之後，利用高分辨穿透式電子顯微鏡結合奈米電子束X光能譜及能量損失譜儀研究多層膜之間奈米尺度的交互擴散。利用一個累積積分法用來做高分辨影像處理以分析晶格常數的變化，而爲改善所測得成份分佈之空間解析度，運用一Wiener過瀘器來移除從奈米電子束X光能譜量測中所產生的電子束延展效應。此外，利用能量損失譜儀，從元素分佈萃取去求界面之粗糙度。結合這些分析技術能更清楚顯現在自旋閥元件超薄多層膜間之相互擴散的訊息。成份分佈的分析顯示Ni已擴散至Cu層。分析的結果亦揭示，在自旋結構，Ru層不只是作爲合成反鐵磁層之間隔層而且似乎亦能當作Ni和Mn元素之擴散阻礙層。爲研究自旋閥元件裹組成元素之擴散機制，簡易地利用Matano-Boltzmann方法來探究組成元素之擴散係數。結果發現對於Cu在Co層、Co在Cu層以及Ni在Co層的擴散，晶界擴散是主要的支配機制。

關鍵字

自旋閥 ； 晶格變化量測 ； 反捲積 ； Matano-Boltzmann方法 ； 晶界擴散

並列摘要

Cap/NiFe/CoFe/Cu/CoFe/Ru/CoFe/NiFe/NiMn/seed layer after the life stress test of the spin-valves read head at 200℃ for 1000 hours is investigated by using high resolution transmission electron microscopy (HRTEM) coupling with nanobeam energy dispersive spectrometer x-ray (EDX) and electron energy loss spectrometer (EELS). Investigation was focused on the interdiffusion among interlayers in the nanometer scale. Accumulated sum technique was applied to analysize the lattice spacing variation across the ultra-thin film from HRTEM micrographs. A Wiener filter was used to remove the electron beam broadening effect from nanobeam EDX data so that the spatial resolution of composition profile is improved. Furthermore, interface roughness was extracted by utilizing EELS map. Combination of these techniques (lattice variation measurement, the deconvolution of nanobeam EDX and EELS maps) allows the insight of interdiffusion among ultra-thin film in the spin-valve device to be revealed. The compositional analysis demonstrated that Ni diffused into the Cu/Co bilayer. The analytical result also suggests that the Ru layer may not only act as the spacer of the synthetic antiferromagnet but also behave as a good diffusion barrier for Ni and Mn element in the spin valve structure. To further study the diffusion mechanism of constituent elements in the spin valve device, the diffusion coefficients of constituent elements are simply investigated using the Matano-Boltzmann method. The diffusion mechanisms of Cu in Co layer, Co in Cu layer and Ni in Co layer were primarily dominated by the grain boundary.

並列關鍵字

Spin valve ； lattice variation measurement ； deconvolution ； Matano-Boltzmann method ； and grain boundary diffusion