以無電鍍法製備純鈷金屬薄膜與空心奈米管之研究

Fabrications of pure Co thin film and hollow Co nanotubes by using the electroless Co deposition technique

許擇倫(Tse-lun Hsu)

指導教授 ： 鄭紹良

國立中央大學/工學院/化學工程與材料工程學系/碩士(2007年)

摘要

無電鍍鈷金屬薄膜由於擁有獨特的化學、磁性和機械性質，近來已經被廣泛的應用在各種工業上。然而，在現有的無電鍍鈷金屬薄膜中，常會發現含有其他的雜質如硼、磷等，這些雜質將會導致其可利用程度降低。因此，急需一個新的無電鍍製程來鍍製純鈷金屬薄膜。
在本研究中，我們利用聯胺作為還原劑，並以一個新的無電鍍製程在矽晶基材上沉積高純度鈷金屬薄膜。首先，將清洗過的(001)矽晶基材分別置入敏化劑(SnCl2/HCl)和活化劑(PdCl2/HCl)中進行前處理步驟。隨後將經過前處理的矽晶試片置入配置好的無電鍍鈷金屬鍍浴中，分別在30-45 ℃之間鍍製6-20分鐘。溶液中的鈷金屬離子藉由聯胺還原反應成鈷金屬，並在矽晶基材上形成一連續鈷金屬薄膜層。經由TEM和SAED分析，可得知所鍍製薄膜為HCP的純鈷金屬多晶相結構。除此之外，藉由EDS的分析所得到的結果，可進一步鑑定得原始鍍製的鈷金屬薄膜只含有純鈷金屬，並無其他雜質。另外，由XTEM的觀察結果可以發現，以無電鍍法鍍製的純鈷金屬薄膜其厚度在30-45 ℃之間時，會隨著時間呈線性增加，我們進一步求出不同溫度時的反應速率，藉由阿瑞尼士方程式我們可求得此純鈷薄膜成長活化能為0.34 eV。
在另一方面，在本研究中我們還嘗試利用以聯胺為還原劑的無電電鍍製程，並以非晶質氧化矽(a-SiOx)奈米線做為模板，配合移除中心模板後法，已可初步製備出大量高純度鈷金屬奈米空心管。實驗中有系統地以SEM、TEM和SAED分別分析觀察不同條件製備的試片的表面形狀、晶體結構和化學組成。

關鍵字

無電鍍鈷金屬

並列摘要

Electroless cobalt film has been widely used for many industrial applications due to its unique chemical, magnetic, and mechanical properties. However, a dramatic amount of impurities (e.g. B or P) were usually found to exist in the electroless Co layers. For microelectronic applications, these impurities would lead to reliability degradation. Therefore, the routes for electroless synthesis of pure Co metal layers are demanded.
In this study, a new and facile route for the electroless deposition of high-purity Co metal thin films on silicon substrate has been developed by using the hydrazine-modified electroless Co deposition processes. The as-cleaned (001)Si substrates were first presensitized and preactivated by treatment with the solutions of SnCl2/HCl and PdCl2/HCl, respectively. Subsequently, the activated Si substrates were immersed into the electroless Co plating baths at 30-45 ℃ for 6-20min. The Co ions were reduced to Co and then deposited onto the surface of the Si substrates to form a continuous Co layer. Form TEM and SAED analysis, diffraction rings corresponding to the pure HCP-Co phase were detected in the SAED pattern, indicating that the crystal structure of the electroless Co layer was polycrystalline. In addition, form EDS analysis, it is clearly shown that the as-deposited Co thin films were entirely composed of pure cobalt. From XTEM observation, the thickness of electroless pure Co thin films was found to increase linearly with plating time at the electroless plating temperatures of 30-45 ℃. Furthermore, by measuring the growth rate at different electroless plating temperatures, the activation energy for the linear growth of the pure Co thin films on blank-(001)Si was obtained from an Arrhenius plot to be about 0.34eV.
On the other hand, in this study, we proposed a new route for the large-scale synthesis of high-purity hollow Co nanotubes by employing the hydrazine-modified electroless Co deposition in conjunction with removable amorphous silicon oxide (a-SiOx) nanowire templates technique. The surface morphology, crystal structure, and chemical composition of the synthesized products were systematically characterized by SEM, TEM, and SAED.

並列關鍵字

electroless pure Co thin film

參考文獻

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