標題: 造成巨大磁場的奈米磁鐵FePt的磁化作用於三氧化二鋁介電質MIM結構中之特性
Giant Magnetic Field in the Magnetization of Nano-Magnet FePt in MIM Structure Using Al2O3 Dielectrics
作者: 吳國源
Wu, Guo-Yuan
張俊彥
Chang, Chun-Yen
電子研究所
關鍵字: 三氧化二鋁;奈米磁鐵FePt;磁化作用;磁退火;Al2O3;nano-magnet FePt;magnetization;magnetic annealing
公開日期: 2012
摘要: 磁性物質的研究及應用相當的廣泛,因此將磁性物質加入半導體製程中以探索新的物理現象。本篇所選用的磁性物質為FePt,而FePt具有相當大的晶格異向性、飽和磁化量和熱穩定性。本研究的主要目標是在奈米等級的空間中產生巨大磁埸,進而研究強磁埸下之電磁效應。例如電流-電壓、電容-電壓、電容-頻率和電容-溫度的特性,甚至磁光效應等。 本論文探討的內容主要分成三個部分,第一部分為磁性MIM結構的製程和磁退火的條件,可以發現FePt的磁性會受不同方式退火所影響。在退火過程的同時施加磁場稱為磁退火製程。第二部分為磁退火系統的設計與演進。此實驗需要將一般退火爐管與電磁鐵整合起來並同時運作,有許多細節或是預料之外的問題,而最後且最主要的問題在於爐管的振動。最後一部分為探討磁性FePt MIM結構之磁性和電性。磁退火製程後,在磁性一面量測出MIM結構裡的飽和磁化率可達21.5 Tesla。根據張俊彥教授理論上的預測,在磁場下電子穿隧機率會降低且電子-光聲子的自由路徑會縮短,這使得磁性FePt MIM結構之漏電流減少,並產生高崩潰電壓。然而經過磁退火製程後,致使有許多新的現象發生,需要有再進一步的討論。
Recently, there are a lot of investigations and applications about magnetic martial. Therefore, to explore new physical mechanisms, magnetic material is introduced into semiconductor processing. The magnetocrystalline anisotropy and saturated magnetization of FePt is larger than other magnetic martials and its chemical stability is better than others. The main goal of this research is to produce giant magnetic field in the space of nanometer scale and investigate the electro-magnetic effects such as characteristics of current-voltage, capacitance-voltage, capacitance-frequency and capacitance-temperature even magneto-optical effects under strong magnetic field. There are three parts in this thesis. First part is the fabrication of MIM structure with nano FePt magnet and the magnetic annealing process. The magnetism of FePt is related to various conditions of annealing. Magnetic annealing process (MAP) means applying magnetic field during furnace annealing. In the second part, many details and unexpected problems during designing and developing magnetic annealing system are described in this part. The main problem is the vibration of furnace. In the last part, we discuss magnetic and electrical characteristics of MIM structure with nano FePt magnet. After magnetic annealing process, the saturation magnetization can achieve 21.5 Tesla. According to prof. Chang’s theoretical predictions, higher breakdown and lower leakage current can be obtained, due to lower electron tunneling probability and shorter electron-optical phonon mean free path under magnetic field can be observed. However, magnetic annealing produces new phenomena which need further investigations are needed.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT079911522
http://hdl.handle.net/11536/49070
顯示於類別:畢業論文