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Quality Improvement of Ultrathin Gate Oxide by Using Thermal Growth Followed by SF ANO Technique
No full textRapid thermal oxide followed by anodization in direct
current superimposed with scanning frequency alternating current
was demonstrated for the first time to have an improved quality
in ultrathin gate oxides. Compared with the thermal oxide grown
without the scanning-frequency anodization (SF ANO) treatment,
the gate leakage current density ( ) of SF ANO sample is significantly
reduced without increasing the thickness of gate oxide. In
addition, it could be observed that the interface trap density ( it)
is reduced with tighter distribution. It is suggested that the bulk
traps and interface traps in thermally grown oxide can be repaired
during the SF ANO process
Intramolecular Hydrogen Bond Effects on Photodissociation of Hydroxybenzoic acids and Hydroxyacetophenone
No full text苯酚為酪胺酸的一個發色團，因此它對光的穩定性就相當重要，由實驗與理論計算得知，在氣相中的分子吸收紫外光後，被激發到ππ*電子激發態，然而ππ*電子激發態與πσ*耦合，最後會經由排斥態從O-H斷鍵，分解出氫原子。為了更進一步研究苯環上不同支鏈對此反應路徑的影響，本實驗選用鄰、間、對-羥基苯甲酸與鄰、間、對-羥基苯乙酮，並利用多重質量離子影像技術來探討個別的光分解機制，對於羥基苯甲酸，間、對羥基苯甲酸主要路徑為氫原子解離，而鄰羥基苯甲酸主要路徑則是H2O的解離，另一方面，鄰、間、對羥基苯乙酮主要光分解路徑都有COCH3的解離，但是只有鄰-羥基苯乙酮觀測不到氫的解離。因此在含有分子內氫鍵的分子，氫原子解離的路徑很明顯被抑制。Phenol is a chromophore of amino acid tyrosine. The photostability of amino acids is very important to life. According to the experimental results and theoretical calculations, phenol absorb an UV photon are excited to ππ* electronic excited state. The ππ* state couples with a πσ* repulsive state. Then the H atom of O-H bond eliminates from the repulsive state. The photodissociation produce the radicals which cause further reaction. That is opposite to the photostability of amino acids. To go a step further to study the effect of the different side chains on H elimination channel, 2-,3-,4-hydroxybenzoic acid and 2-,3-,4-hydroxyacetophenone are chosen in this experiment. We study the photodissociation of each compound by using multimass ion imaging technique. For hydroxybenzoic acid, H elimination is the major channel for 3-,4-hydroxybenzoic acid and H2O elimination is the major channel for 2-hydroxybenzoic acid. On the other hand, COCH3 elimination is the major channel for 2-, 3-, 4-hydroxyacetophenone. H elimination is observed for 3-, 4-hydroxyacetophenone but it is not observed for 2-hydroxyacetophenone. In comparison with photodissociation channels and molecular structures, H elimination from the repulsive excited state is quenched for the molecules
with intramolecular hydrogen bond
Compensation Technique of Ultra-Thin Oxide in D.I. Water and the Effect of Hydrogen on the Reliability of Oxide-Nitride-Oxide (ONO) Dielectrics
No full text在這個研究中，我們提出了掃描頻率陽極氧化(Scanning-frequency Anodization)修補的方法來修補超薄二氧化矽氧化層(SiO2)以增進其特性。我們所使用的掃描頻率為20赫茲到200k赫茲。在經過掃描頻率修補之後，厚度為18Å的二氧化矽氧化層，其在-2V之閘極漏電流密度(Gate Leakage Current Density)為1.5A/cm2，較相同厚度未經修補之二氧化矽氧化層降低了75%。除此之外，在經過掃描頻率陽極氧化修補之後，其界面缺陷密度(Dit)也減少了20%。為高介電常數(High-k)材料的氧化鋁(Al2O3)有在低電場下低漏電流及在高電場下高穿隧電流的特性，因此我們用來取代MONOS型式非揮發性記憶體中的二氧化矽氧化層。我們用-16V抹除(Erase)10ms，可達到6V的平帶電壓(Flatband Voltage)横移。其10年投影預測之寫入(Program)/抹除電壓差，在室溫及85oC下，分別為5.3V及4.9V。們在研究中也發現，在400oC或更高的溫度之下以氫氣烘烤，能夠抹除以氮化矽為儲存層的電荷儲存記憶體中的儲存電子。無論原先的平帶電壓為何，在元件周邊區域經過高溫氫處理之後，所有的平帶電壓值都會相同。但氫只會影響有儲存電荷的區域，若元件中沒有儲存電荷，則不受影響。此特性可以解決紫外光或是電漿所引起的周邊電荷儲存問題。經過紫外光照射而有周邊電荷儲存的記憶體元件在400oC下僅需15分鐘即可抹除其儲存電荷。In this work, a method named scanning-frequency anodization (SF-ANO) was proposed to improve the quality of ultra-thin thermally grown SiO2. The frequency condition of SF is from 20Hz to 200kHz. After SF-ANO treatment, the gate leakage current of 18Å SiO2 is 1.5A/cm2 at -2 V, which is 75% off compare with the device with the same thickness without ANO treatment. Besides, 25% reduction in interface trap density (Dit) can also be observed after SF-ANO treatment. igh performance trap-less MAD Al2O3 was then used to replace the tunnel and block layer in MONOS type flash memory because of the suppressed gate leakage current at low electric field and enhanced tunneling current at high electric field, and a MANAS stack is obtained. 6V erase window can be achieved in 10ms by using -16V erase voltage. Besides, the 10-year projected retention window is as large as 4.9V at 85oC, and 5.3V at RT.ydrogen is found to invade into nitride-based charge trapping memory stack from the edge and neutralize the trapping electrons as baking at temperature of 400oC or above. Regardless of the programmed flatband voltages (VFB) are, all the devices had the same VFB at the edge of the devices. Hydrogen invasion occurs only in the programmed ONO devices; a non-programmed ONO device would not be affected. The experimental results are suggested to solve the problems of UV or plasma induced charge trapping. The UV induced trapping charges can be eliminated in 15 minutes as baking at 400oC.Abstract (Chinese)……………………………………………………..Ⅰbstract (English)……………………………………………………..Ⅱontents………………………………………………………………..Ⅲigure Captions……………………………………………..…………Ⅴable Captions…………………………………………………………Ⅸhapter 1 Introduction-1 Scaling of MOSFETs ……………………………………………...………1-1-1 Passivation of Ultrathin SiO2………………………………………..3-1-2 Issues of High-k Gate Dielectric……………………………………..4-2 Determination of Ultrathin Oxide Thickness by Utilizing Quantum Mechanical Fitting ………………………………………………………..7-3 Brief of Non-volatile Charge Trapping Memory ………………………10-4 About this work ………………………………………………………….14hapter 2 Quality Improvement in Electrical Characteristics of Ultrathin Thermally Grown Oxides Compensated by SF-ANO Technique 2-1 Introduction ……………………….……………..…..…………………...23 2-2 Experimental ……………………………………………………………..242-2-1 Overview of Rapid Thermal Process System ……………………..242-2-2 Experimental Setup of DAC Anodization Process ……………….252-2-3 Device Fabrication and Measurement …………………………….25 2-3 Characterization of Ultrathin Thermally Grown Oxides Compensated By SF-ANO …………………………………………….…………………26 2-4 Summary …………………………………………………………………29hapter 3 High Quality Al2O3 Prepared by Molecular-Atomic Deposition (MAD) and Its Application in Tunnel Layer of Charge Trapping Memory-1 Introduction …………………………………………….………………...37-2 Overview of Molecular-Atomic Deposition (MAD) System ….………..39-3 Device Fabrication ……………………………………………………….41-4 Experimental Results ……………………………………………….……42-4-1 Performance of MAD Al2O3 ………………………………………..42-4-2 Characteristics of MANAS Stack ………………………………….43-5 Summary ……………………………………………….…………………44hapter 4 Modeling and Characterization of Hydrogen Induced Charges Loss in Nitride Trapping Memory and Its Application-1 Introduction ……………………………………………………………..55-2 Device Fabrication ……………………………………………………….57-3 The Hydrogen Induced Flatband Voltage Shift ………………………..584-3-1 Hydrogen Effects on Al Gate Devices ……………………………..604-3-2 Hydrogen Effects on Poly Gate Devices …………………………..61-4 Hydrogen Diffusion Model and Mechanism of Flatband Voltage Shift ……………………………………………………………………….63 4-5 Application of Hydrogen Erasing in UV Charged Device …………….67 4-6 Ability of Re-programming in Hydrogen Erased Device ……………...71 4-7 Reliability of Hydrogen Erased Device …………………………………73 4-8 Summary ……………………………………………….…………………74hapter 5 Conclusion 5-1 Conclusions ……………………………………………………………..105 5-2 Suggestions for Future Work …………………………………………..107eference…………10
Modeling and Characterization of Hydrogen Induced Charge Loss in Nitride Trapping Memory
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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