臺灣博碩士論文加值系統

隨著3C與車載產業的應用來臨，被動元件的需求大增，而本計畫主要研究超高介電常數（εr>200,000）之陶瓷材料。過往文獻中提出鈦酸鍶鈣 （簡稱STO），添加五氧化二鈮（Nb2O5）在缺氧環境下燒結後的陶瓷材料具有高介電常數之特性且不易受溫度與頻率之影響，然而其相關機制並不完整。吾人團隊將STO添加不同比例之Nb2O5，且在缺氧環境下高溫燒結以進行介電特性與微觀之研究。首先合成STO陶瓷材料做了XRD之分析，其相結構為立方晶（Cubic），之後微量添加Nb2O5進行高溫燒結分別是大氣（Air）和氮氫氣氛（NH）作為對照。其介電常數（εr）顯示隨著Nb2O5添加從0-2.5wt%時，大氣下燒結之介電常數（εr）仍維持在200~400範圍之間，而若在氮氫氣氛下燒結，則介電常數（εr）則從300增加至370,000 （1.45wt% Nb2O5添加時），且絕緣電阻（IR）從1012降為105。
此外，在不同氣氛下XRD分析皆並未發現二次相，而氮氫氣氛燒結的樣品Peak先往低角度移動後再往高角度移動，顯示Nb2O5進入TiO2位置。
另外利用拉曼光譜發現隨著Nb2O5的添加，氧鍵結的強度變弱，表示氧的鍵結力越來越弱；進一步利用同步輻射之吸收光譜實驗觀察不同比例Nb2O5的Ti L-edge。Ti的吸收光譜並沒有太大的改變，而O K-edge的eg /T2g 比值從0.88升到1.01。這表示氧的鍵結越來越弱，導致氧失去了束縛且未與Ti結合，從拉曼與同步輻射結果可知Nb2O5添加後，在氮氫氣氛下燒結，產生大量氧空缺。以TEM觀察，STN-1.45wt%的試片，顯示大量的差排環產生。因此，本次實驗結果顯示，Nb2O5的添加於STO材料，並在缺氧環境下燒結，由於Nb5+進入Ti4+，不但發生施體行為使得自由電子增加而造成絕緣電阻降低。另外，Nb2O5添加也會產生大量氧空缺，因此缺陷偶極現象提高了介電常數（εr）。故此材料具有發展的潛力，可應用於被動電子元件上。

With increasing application in electronics and automobile industry, demand for passive components is on the rise. This project is aimed to develop Ultra-high dielectric constant (εr>200,000) ceramic materials. Literature survey shows that ceramic materials produced from the high temperature sintering of Nb2O5 doped in Sr0.9Ca0.1TiO3 (STO) under the oxygen deficit environment are with ultra-high dielectric constant (εr) and less likely to be subject to the temperature and frequency, yet relative mechanisms remain incomplete.
The research team has tried to dope STO with different ratio of Nb2O5 and to have them burnt under the oxygen deficit environment to conduct study on dielectric properties and microstructure. Firstly, XRD analysis is conducted on synthetic STO ceramic materials, of which the microstructure is cubic. Then, small amount of Nb2O5 is added for high temperature sintering for comparison study on air (Air) atmosphere and N2-H2 (NH) atmosphere. The dielectric constant (εr) shows that when 0-2.5wt% Nb2O5 is doped, dielectric constant (εr) remains at the level of 200~400 under the high temperature sintering in air atmosphere, while dielectric constant (εr) surges from 300 to 370,000 in N2-H2 atmosphere (with 1.45mol% Nb2O5 doped) and insulation resistance changes from 1012 to 105.
In addition, XRD analysis shows there is no second phase found in different atmospheres. The peak of sample in N2-H2 atmosphere moves to high angle after low angels, showing the entry position of Nb2O5 into TiO2. Besides, Raman spectra analysis shows that with the doping of Nb2O5, oxygen bond becomes weaker. Further synchrotron X-ray absorption spectra observes Ti L-edge of different Nb2O5 ratios. The absorption spectra of Ti have no major changes, while eg/T2g (Ratio) of O K-edge increase from 0.88 to 1.01. This demonstrates that oxygen cannot be bonded with Ti with weaker oxygen bonding. The results of Raman spectra and synchrotron X-ray absorption spectra shows that the high temperature sintering in N2-H2 atmosphere of Nb2O5 doped in STO will create mass amount of oxygen vacancy. Following TEM test shows that with the ratio of STN-1.45wt%, there is a large amount of dislocation loop.
In conclusion, the study shows that the sintering of Nb2O5 doped in STO in oxygen deficit environment will not only create donor behavior which increases free electron and decreases insulation resistance (IR) because Nb5+ enters Ti4+, but also creates large amount of oxygen vacancy. The defect dipole increases dielectric constant. Therefore, this material has development potentials to be applied in passive components.

指導教授推薦書 i
口試委員審定書 ii
中文摘要 iii
Abstract iv
目錄 vi
圖目錄 ix
表目錄 xi
第一章　緒論 1
1. 1 前言 1
1. 2 研究動機 2
1. 3 研究目的 4
第二章 文獻回顧 5
2. 1 毫米波介電材料原理與文獻 5
2. 2 介電材料概論 5
2.2.1 介電常數（dielectric constant, εr） 6
2.2.2 損耗因子（Dissipation factor, Df） 10
2.2.3 品質因子（Quality factor, Q） 10
2. 3 金屬氧化物半導體（metal-oxide semiconductor） 11
2. 4 鈣鈦礦相的結構與組成 11
2. 5 鈦酸鍶陶瓷之缺陷極化機制 13
2.5.1 鈦酸鍶陶瓷之還原氣氛機制 13
2.5.2 鈦酸鍶陶瓷之施體行為 14
2.5.3 鈦酸鍶陶瓷之受體行為 15
第三章 實驗步驟與分析方法 16
3. 1 實驗步驟 16
3. 2 實驗儀器規格表 20
3. 3 X-ray 繞射儀 （X-ray diffractometer, XRD） 22
3. 4 場發射掃描式電子顯微鏡 （field emission scanning electron microscope, FESEM） 24
3.4.1 能量分散光譜儀 （energy dispersive spectroscopy, EDS） 24
3. 5 光致發光 （photoluminescence, PL） 25
3. 6 電感電容阻抗測試儀 （inductance capacitance resistance, LCR） 26
3. 7 拉曼散射光譜儀（raman spectroscopy, Raman） 27
3. 8 穿透式電子顯微鏡（transmission electron microscope, TEM） 28
第四章 研究結果與討論 30
4. 1 鈦酸鍶陶瓷摻雜鈮於不同氣氛燒結之介電特性 30
4. 2 SEM微觀之結構與探討 33
4. 3 XRD相結構分析與探討 35
4. 4 Raman散射光譜分析與探討 37
4. 5 XAS吸收光譜分析與探討 39
4. 6 TEM分析與探討 41
第五章 結論 46
參考文獻 48


圖目錄
圖 1 1 5G產業鏈圖 2
圖 2 1不同頻率的種類與範圍 5
圖 2 2 電子極化 6
圖 2 3 離子極化 7
圖 2 4 取向極化 7
圖 2 5 界面極化 8
圖 2 6 不同極化下介電常數和頻率之關係圖 9
圖 2 7 SrTiO3之晶體結構 11
圖 2 8 SrTiO3之XRD 12
圖 3 1 材料製程 17
圖 3 2 升溫曲線 18
圖 3 3 氣氛製程 19
圖 3 4 大氣氣氛升溫曲線 19
圖 3 5氮氫氣氛升溫曲線 20
圖 3 6 XRD之繞射原理 23
圖 3 7 XRD之貴儀 23
圖 3 8 FESEM之貴儀 24
圖 3 9 新竹同步輻射中心-光束線 26
圖 3 10 樣品之燒銀升溫曲線 27
圖 3 11 拉曼散射光譜儀 28
圖 3 12 TEM之貴儀 29
圖 4 1 不同氣氛之介電常數（εr） 30
圖 4 2 不同氣氛之絕緣電組（IR） 31
圖 4 3 不同氣氛STN之Df值 32
圖 4 4 在氮氫氣氛下STN之縮率 33
圖 4 5 大氣氣氛STN之SEM影像（SEI） 34
圖 4 6 氮氫氣氛STN之SEM影像（SEI） 35
圖 4 7 SrTiO3之XRD 36
圖 4 8 氮氫氣氛SNT之XRD 37
圖 4 9 大氣氣氛STN之Raman shift 38
圖 4 10 氮氫氣氛STN之Raman shift 39
圖 4 11 氮氫氣氛STN之XAS 40
圖 4 12 eg/t2g之比值 41
圖 4 13 氮氫氣氛下STN-1.45wt%之TEM微觀影像（BFI） 42
圖 4 14 氮氫氣氛下STN-2.05wt%之TEM微觀影像（BFI） 44
圖 4 15氮氫氣氛下STN之TEM微觀影像（BFI） 45




 
表目錄
表 2 1 離子半徑表 12
表 2 2 金屬氧化物和鐵電材料系列之介電特性 13
表 3 1 化學藥品名稱 17
表 3 2 儀器名稱、來源、用途 20
表 4 1 STN-1.45wt%之Sit1~Site4元素分析 42
表 4 2 STN-1.45wt%之Site5~Site8元素分析 43
表 4 3 STN-1.45wt%之Site9、Site10元素分析 43
表 4 4 STN-1.45wt%之Site1~Site6元素分析 44

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