巨磁阻感測元件的製作與量測

Fabrication and testing of giant magnetoresistance sensing elements

林振湋

指導教授 ： 衛榮漢

國立清華大學/工學院/動力機械工程學系/碩士(2009年)

摘要

磁性感測元件目前在工業製具的線性移動系統與角度定位系統
中都有廣泛的應用，因此對其電性的了解以及參數的最佳化均相當重
要。本研究利用微機電技術與巨磁阻效應，設計並製作一個以惠斯同
電橋為電路架構之巨磁阻感測元件，並將此元件與線性滑軌及磁性刻
度尺整合，再配合外部電路，藉此達到極精準的線性位移控制。本文
同時對磁性元件的參數做最佳化研究，透過改變膜層結構厚度、磁膜
邊緣形狀以及利用多層堆疊的方式來進行參數最佳化，也就是磁電阻
變化率的改善。
實驗結果發現自由層膜厚的改變會使得磁電阻變化率降低以及
線性應用區段縮減；邊緣形狀的加入則有助於改善輸出波形；金屬導
線邊緣、圓形邊緣、橢圓形邊緣以及鏈球狀等均可改善輸出波形。而
多層膜堆疊則會增加磁電阻變化率，但由於分流效應造成效果較弱。

關鍵字

邊緣效應 ； 多層堆疊 ； 巨磁阻

並列摘要

Magnetic sensing elements have been used extensively in industrial
equipments, so the research for the electrical characteristics of sensing
elements and the optimization of its parameters has become more and
more important. Based on the technique of micro electro mechanical
systems (MEMS) and giant magnetoresistance (GMR) effect, a
bridge-type GMR sensing element had been designed and produced. This
element is combined with a linear guideway and a magnetic encoder, and
precise displacement control can be performed by integrating it with
outside electric circuits. Optimization of parameters had studied by
changing the layer thickness of structure, different shapes of magnetic
films and multilayer effect for the improvement of the magnetoresistance
ratio.
The experimental results show that the magnetoresistance ratio and
the linear application section are shrinked by changing the thickness of
free layer. The different edge shapes of magnetic films changes the output
signal of the system, shapes such as metal wire end, circular end, elliptic
end, and chained ball type can cause the output signal fixed. The effect of
multilayer increases magnetoresistance ratio, but does not obvious due to
the shunting effect.

並列關鍵字

Edge Effect ； Multilayer ； GMR

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