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TEM Observation and Analysis of Porous Silicon
No full text多孔矽早於1956便被發現，由於其獨特的光學與電學性質，在這數十年來一直受到矚目，對於造成這獨特光、電性質的原因仍是眾說紛紜，有人認為是奈米柱（nano-rod）、有人則認為是海綿狀多孔結構中的奈米晶粒所造成[1]。然而受限於早期電子顯微鏡設備與技術，僅能得知其中、低倍形貌，而無法得知其奈米尺度之結構，現今多孔矽研究則以其應用為主，對其基本結構則少有著墨。因此，此研究中將以場發射穿透式電子顯微鏡輔以電子能量散佈偵測器（EDX）及電子能量損失偵測器（EELS）來探討其奈米尺度結構。此外，在多孔矽製備上則是以非揮發性記憶體（non-volatile memory）的應用為目標，期望在多孔矽層內形成奈米晶粒，因此在此研究中亦探討多孔矽製程參數對其形貌與結構之影響。
在此研究中，多孔矽膜的製備是將矽基材於氟化氫溶液中進行陽極處理，再進行快速熱氧化而得到。此結構中可得到尺寸約為3~5 nm的奈米晶粒。在改變快速熱氧化時間的實驗中，得知十秒的熱處理時間即可使氧化層厚度達到穩定，約為160 nm。經鍺電鍍後之P+多孔隙膜，，於表面會形成一層約9 nm的矽鍺結晶層。而於900oC與1000oC回火過後鍍鍺多孔矽膜於多孔矽與矽基材介面處會產生V形孔洞，其側壁平行於矽基材(1 1 1)族平面。
在本文中：
第一章、簡介：將對本研究作簡介並對各章節作概要述說
第二章、前言：將對多孔矽結構與特性及其潛力以及未來非揮發性記憶體對閘極材料的需求作介紹
第三章、文獻回顧：將對說明不同多孔矽製作設備、程序以及至程參數條件對多孔矽形貌的影響。另整理了對於矽溶解化學反應與孔洞形成機制的理論。
第四章、實驗：分為兩部分，一為多孔矽試片製備流程；另一則是半導體TEM試片製備方法。
第五章、結果與討論：分別對於不同製程參數及及熱處理條件下的多孔矽進行觀察與分析，其中包含：多孔矽原始形貌觀察、氧離子佈植對多孔矽之影響、以改變陽極處理電流製備多孔矽單層與三層結構、不同1000 oC RTO熱處理時間對多孔矽層結構的影響、於氫氣氛下1000 oC快速熱回火對多孔矽層結構的影響、不同陽極處理條件對p+型多孔矽結構之影響、RTA熱處理對鍍鍺多孔隙膜之影響、900℃與1000℃RTA熱處理對鍍鍺多孔隙膜之影響、多孔矽膜中之鍺元素分佈之影響以及多孔矽表面之緻密結晶層。
第六章、結論：對於以上研究作一歸納總結。Porous silicon was discovered since 1956, due to its unique optical and electrical properties, it’s still remaining in focus in these decades. The reasons that cause these unique properties are still a puzzle. Someone says that’s because of nano-rod, another thinks it’s due to nano-crystal inside the sponge-like structure. However, there are limitations in the electron microscopy technique and equipment in the past, the morphology of the structure can only observed at low and medium magnification, so there is little information about the structure in nano scale. The researches now a day in porous silicon are for applications, most of them are not focus on its basic structure. Here, the research will using field emission gun TEM equipped with energy dispersion x-ray (EDX) detector and electron energy loss spectroscopy (EELS) detector to analyze its structure in nano-scale. In addition, the purpose of this porous silicon is for non-volatile memory application, we expect there will be nano-crystals formed in the porous silicon layer. So the effect of fabrication process parameters to the morphology and structure is also discussed in this research.
In this research, the porous silicon is fabricated using anodic treatment to the silicon wafer in hydro fluoride solution, followed by rapid thermal oxidation. In this structure, the nanocrystals can be observed with the size in 3~5 nm. For the specimens with different thermal oxidation time, the variation of oxide thickness reaches stable after ten seconds heat treatment, which is about 160 nm. The p+ porous silicon with germanium electroplated has a silicon-germanium crystallized layer with 9 nm thickness at the surface of porous silicon layer. There are V shape voids formed near the interface of porous silicon and silicon in the germanium electroplated p+ porous silicon specimen after 900oC and 1000oC rapid thermal annealing, the side wall of void is parallel to (1 1 1) plans of silicon substrate.
The brief introduction to each chapter of this thesis is descried below:
Chapter One, Abstract: will give a brief introduction to this research and each chapter of this thesis.
Chapter Two, Introduction: will give an introduction to the structure, characteristics and potential of porous silicon, and the need for gate material in non-volatile memory in the future.
Chapter Three, Paper review: Will describe different method and equipment to fabricate porous silicon and the effect of parameters in fabrication process to the morphology of porous silicon. In addition, it also describes several theories about silicon dissolution chemical reactions and pits formation mechanisms.
Chapter Four, Experiment: it divided into two parts; one is the fabrication procedure of porous silicon, another is TEM specimen preparation of semiconductor material.
Chapter Five, Result and discussion: will describe the observation and analysis of porous silicon with different process parameters and heat treatment conditions, which include: observation of porous silicon after anodic treatment, the effect of oxygen ion implantation to porous silicon layer, preparation of single and triple layer porous silicon by changing anodic treatment current, the effect of 1000oC RTO treatment to the structure of porous silicon layer, the effect of 1000oC RTO treatment under hydrogen atmosphere to porous silicon layer, the effect of different anodic treatment parameters to p+ porous silicon layer, the effect of 900oC and 1000oC RTA treatment to germanium electroplated porous silicon layer and the analysis of germanium distribution in porous silicon layer.
Chapter Six, Conclusion: a summary to the research.多孔矽結構之電子顯微鏡觀察與分析 0
1. 摘要 1
2. 前言 6
3. 文獻回顧 11
3.1. 多孔矽的形成 11
3.2. 電流—電壓（Current - Voltage）特徵 13
3.3. 溶解化學反應 14
3.4. 孔洞的形成 15
3.5. 陽極處理條件之影響 18
4. 實驗 27
4.1. Porous Silicon試片製備 27
4.1.1. 電化學陽極處理 27
4.1.2. 快速熱氧化與快速熱回火 28
4.1. TEM橫截面試片製備 30
4.1.1. 半導體試片製備簡介 30
4.1.2. 試片製備工具 34
4.1.3. TEM橫截面（cross-section）試片製作程序 38
5. 結果與討論 44
5.1. 多孔矽原始形貌觀察 44
5.1.1. 經陽極處理後之矽晶片 44
5.1.2. 經RTA熱處理後之多孔矽 45
5.2. 氧離子佈植對多孔矽之影響 46
5.2.1. 氧離子佈植影響 46
5.3. 以改變陽極處理電流製備多孔矽單層與三層結構 47
5.3.1. 多孔矽單層結構 48
5.3.2. 多孔矽三層結構 49
5.4. 不同1000 oC RTO熱處理時間對多孔矽層結構的影響 50
5.5. 於氫氣氛下1000 oC快速熱回火對多孔矽層結構的影響 51
5.6. 不同陽極處理條件對p+型多孔矽結構之影響 52
5.7. RTA熱處理對鍍鍺多孔隙膜之影響 54
5.8. 900℃與1000℃RTA熱處理對鍍鍺多孔隙膜之影響 58
5.9. 多孔矽膜中之鍺元素分佈 60
5.10. 多孔矽表面之緻密結晶層 61
6. 結論 63
7. 著作 65
參考文獻 11
Shared work values and team member effectiveness: The mediation of trustfulness and trustworthiness
No full text
Effective Tunnel-based Multi-path BGP routing Using Software-Defined Networking
No full text這篇論文中提出一個利用軟體定義網路進行基於網路通道之多路徑BGP路由的演算法。BGP是目前在網際網路上唯一一個被廣泛部署之域間路由演算法，且從該標準提出後多年至今的數十年間無大規模修改。BGP基於目的位置的路由方式導致網路中局部連結過載，而其他部分連結使用量過低。先前已有許多研究提出多路徑路由演算法，但這些研究專注於位置之可達性與路徑之傳播，而這些研究均無考慮到路徑之可乘載容量。 當雍塞發生時，封包遺失與控制雍塞機制會使傳送之頻寬下降，即時串流應用無法獲得足夠的頻寬，使服務無法使用。傳統域間流量規劃技術仍受BGP目的位置路由之限制，無法完全控制路由路徑。這篇論文中，目的端可以給予來源端路徑品質之回饋。這些回饋會被用來偵測路徑上之雍塞，來源端以此來調整路由。 透過建立跨越自治系統之網路通道來克服BGP之限制。在有明確網路通道之流量需求資訊下，實驗結果顯示出可以降低網路之雍塞程度。This thesis presents a tunnel-based multi-path inter-domain routing algorithm under Border Gateway Protocol (BGP) environment using Software-defined Networking. BGP has been the only widely-deployed inter-domain routing protocol on the Internet, and remains little changes over decades. The destination-based routing nature of BGP is known to overload popular links on the Internet, while making some links under-utilized. Prior works had proposed multi-path inter-domain routing protocols. These works focus on reachability and propagation of multi-path information. None of them take the capacity of the path into consideration. In the presense of congestion, packet loss and congestion avoidance mechanisms can lead to inadequate bandwidth required for realtime streaming, making services unusable. Traditional traffic engineering techniques over inter-domain are still limited by destination-based nature of BGP, which is unable to fully control the route. In this thesis, destinations can provide feedback about path quality to the source. The feedback is used to detect congestions on routes and for source to adjust routes accordingly. Tunnels are allocated over Autonomous Systems to overcome the limitation of BGP. With explicitly knowing the demand of tunnels, evaluation shows reduced congestions over the networks
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koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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