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Study of Disposable EGFET-based Hydrogen and Potassium Micro Ion SensorsChang, Chih-Han 08 April 2010 (has links)
In recent years, as biological information analysis technology rapidly develops in hematology, biochemistry and microbiology areas, demand for portable measurement systems become more and more important. This study makes efforts in developing disposable hydrogen and potassium ion sensor and microsystem for analysis application. The measured ion concentration data by this analysis microsystem provide people a judgement on their health condition, and furthermore an important reference for medical treatment for patients.
There are several advantages in using IC or MEMS technology to manufacture portable measurement system, the advantages are down-scaling, short reaction time, trace chemical analysis, low power dissipation, and low cost. So the thesis uses extended gate field effect transistor, in order to measure multiple ions at the same time, multiple transistors are manufactured on the same chip with an ion selective membrane on top of the gate sensitive layer. This allows the measurement result of the multiple ion be shown at the same time. The main processing steps of the ion sensor developed in this study involve at least four photolithographic and three thin-film deposition processes.
Based on the measurement result, the hydrogen ion sensor¡¦s sensitivity is 30.7 mV/decade for a sensing range pH1 ~ pH13. The sensitivity of the potassium ion sensor is 11.5 mV/decade for a sensing range 10-1M to 10-3M.
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Hafnium-doped tantalum oxide high-k gate dielectric films for future CMOS technologyLu, Jiang 25 April 2007 (has links)
A novel high-k gate dielectric material, i.e., hafnium-doped tantalum oxide (Hf-doped
TaOx), has been studied for the application of the future generation metal-oxidesemiconductor
field effect transistor (MOSFET). The film's electrical, chemical, and
structural properties were investigated experimentally. The incorporation of Hf into TaOx
impacted the electrical properties. The doping process improved the effective dielectric
constant, reduced the fixed charge density, and increased the dielectric strength. The
leakage current density also decreased with the Hf doping concentration. MOS capacitors
with sub-2.0 nm equivalent oxide thickness (EOT) have been achieved with the lightly
Hf-doped TaOx. The low leakage currents and high dielectric constants of the doped films
were explained by their compositions and bond structures. The Hf-doped TaOx film is a
potential high-k gate dielectric for future MOS transistors.
A 5 ÃÂ
tantalum nitride (TaNx) interface layer has been inserted between the Hf-doped
TaOx films and the Si substrate to engineer the high-k/Si interface layer formation and
properties. The electrical characterization result shows that the insertion of a 5 ÃÂ
TaNx
between the doped TaOx films and the Si substrate decreased the film's leakage current density and improved the effective dielectric constant (keffective) value. The improvement
of these dielectric properties can be attributed to the formation of the TaOxNy interfacial
layer after high temperature O2 annealing. The main drawback of the TaNx interface layer
is the high interface density of states and hysteresis, which needs to be decreased.
Advanced metal nitride gate electrodes, e.g., tantalum nitride, molybdenum nitride,
and tungsten nitride, were investigated as the gate electrodes for atomic layer deposition
(ALD) HfO2 high-k dielectric material. Their physical and electrical properties were
affected by the post metallization annealing (PMA) treatment conditions. Work functions
of these three gate electrodes are suitable for NMOS applications after 800ðC PMA.
Metal nitrides can be used as the gate electrode materials for the HfO2 high-k film.
The novel high-k gate stack structures studied in this study are promising candidates
to replace the traditional poly-Si-SiO2 gate stack structure for the future CMOS
technology node.
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Geology and mineralogy of tantalum and niobium deposits in Southern ChinaTsang, Hin-yuen., 曾獻源. January 2010 (has links)
published_or_final_version / Applied Geosciences / Master / Master of Science
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A study on the material and device characteristics of hafnium oxynitride MOSFETs with TaN gate electrodesKang, Changseok 28 August 2008 (has links)
Not available / text
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Interface engineering and reliability characteristics of HfO₂ with poly Si gate and dual metal (Ru-Ta alloy, Ru) gate electrode for beyond 65nm technologyKim, Young-Hee 28 August 2008 (has links)
Not available / text
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Scaling and process effect on electromigration reliability for Cu/low k interconnectsPyun, Jung Woo, 1970- 28 August 2008 (has links)
The microelectronics industry has been managing the RC delay problem arising from aggressive line scaling, by replacing aluminum (Al) by copper (Cu) and oxide dielectric by low-k dielectric. Electromigration (EM) turned out to be a serious reliability problem for Cu interconnects due to the implementation of mechanically weaker low-k dielectrics. In addition, line width and via size scaling resulted in the need of a novel diffusion barrier, which should be uniform and thin. The objective of this dissertation is to investigate the impacts of Ta barrier process, such as barrier-first and pre-clean first, and scaling of barrier and line/via on EM reliability of Cu/low-k interconnects. For this purpose, EM statistical test structures, having different number of line segments, line width, and via width, were designed. The EM test structures were fabricated by a dualdamascene process with two metal layers (M1/Via/M2), which were then packaged for EM tests. The package-level EM tests were performed in a specially designed vacuum chamber with pure nitrogen environment. The novel barrier deposition process, called barrier-first, showed a higher (jL)[subscript c] product and prolonged EM lifetime, compared with the conventional Ta barrier deposition process, known as pre-clean first. This can be attributed to the improved uniformity and thickness of the Ta layer on the via and trench, as confirmed by TEM. As for the barrier thickness effect, the (jL)c product decreased with decreasing thickness, due to reduced Cu confinement. A direct correlation between via size and EM reliability was found; namely, EM lifetime and statistics degraded with via size. This can be attributed to the fact that critical void length to cause open circuit is about the size of via width. To investigate further line scaling effect on EM reliability, SiON (siliconoxynitride) trenchfilling process was introduced to fabricate 60-nm lines, corresponding to 45-nm technology, using a conventional, wider line lithograph technology. The EM lifetime of 60-nm fine lines with SiON filling was longer than that of a standard damascene structure, which can be attributed to a distinct via/metal-1 configuration in reducing process-induced defects at the via/metal-1 interface. / text
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Investigation of Pt supported on carbon, ZrO2, Ta2O5 and Nb2O5 as electrocatalysts for the electro–oxidation of SO2 / Boitshoko Goitseone ModingwaneModingwane, Boitshoko Goitseone January 2011 (has links)
The gradual depletion of and dependence on fossil fuels, air pollution and global
warming have all accelerated the development of alternative energy systems which use
hydrogen as an energy carrier. The hybrid sulphur cycle (HyS) is the foremost electrothermochemical
process that can produce hydrogen as the energy carrier.
The HyS cycle consists of two units, namely the sulphuric acid decomposition reactor
and the sulphur dioxide electrolyser (SDE). The SDE is responsible for the SO2 electrooxidation
to sulphuric acid and protons at the anode and the electro–reduction of
protons to hydrogen at the cathode. This research study focuses on the kinetic data
collected from the prepared catalysts for SO2 electro–oxidation at the anode.
Platinum dispersed on carbon, niobium pentoxide, tantalum pentoxide and zirconium
dioxide as electrocatalysts were prepared using sodium borohydride as a reducing
agent. These electrocatalysts were characterized using transmission electron
microscopy and x–ray diffraction. Cyclic voltammetry was used to study the
electrochemical active surface area (EAS) and the results showed that Pt/ZrO2–C had a
higher EAS area than Pt/Ta2O5–C, Pt/Nb2O5–C and Pt/C. The high EAS of Pt/ZrO2–C
can be explained by the low crystal size however after a series of linear polarisation
scans Pt/ZrO2–C experiences a much greater area loss than all the other catalysts.
Linear polarisation scans for each of the catalysts revealed that the influence of
increased temperature and sulphuric acid concentration were showed improved
results. Levich and Koutecky–Levich plots revealed that the SO2 oxidation is a multistep
reaction on all the prepared catalysts and that there are regions which are kinetic and
diffusion controlled and diffusion–only controlled. Pt/Ta2O5–C catalysts exhibited
superior catalytic activity and stability compared Pt/Nb2O5–C, Pt/ZrO2–C and Pt/C. The
Pt/ZrO2–C exhibited the most inferior catalytic activity and stability. / Thesis (M.Sc. (Chemistry))--North-West University, Potchefstroom Campus, 2011.
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Investigation of Pt supported on carbon, ZrO2, Ta2O5 and Nb2O5 as electrocatalysts for the electro–oxidation of SO2 / Boitshoko Goitseone ModingwaneModingwane, Boitshoko Goitseone January 2011 (has links)
The gradual depletion of and dependence on fossil fuels, air pollution and global
warming have all accelerated the development of alternative energy systems which use
hydrogen as an energy carrier. The hybrid sulphur cycle (HyS) is the foremost electrothermochemical
process that can produce hydrogen as the energy carrier.
The HyS cycle consists of two units, namely the sulphuric acid decomposition reactor
and the sulphur dioxide electrolyser (SDE). The SDE is responsible for the SO2 electrooxidation
to sulphuric acid and protons at the anode and the electro–reduction of
protons to hydrogen at the cathode. This research study focuses on the kinetic data
collected from the prepared catalysts for SO2 electro–oxidation at the anode.
Platinum dispersed on carbon, niobium pentoxide, tantalum pentoxide and zirconium
dioxide as electrocatalysts were prepared using sodium borohydride as a reducing
agent. These electrocatalysts were characterized using transmission electron
microscopy and x–ray diffraction. Cyclic voltammetry was used to study the
electrochemical active surface area (EAS) and the results showed that Pt/ZrO2–C had a
higher EAS area than Pt/Ta2O5–C, Pt/Nb2O5–C and Pt/C. The high EAS of Pt/ZrO2–C
can be explained by the low crystal size however after a series of linear polarisation
scans Pt/ZrO2–C experiences a much greater area loss than all the other catalysts.
Linear polarisation scans for each of the catalysts revealed that the influence of
increased temperature and sulphuric acid concentration were showed improved
results. Levich and Koutecky–Levich plots revealed that the SO2 oxidation is a multistep
reaction on all the prepared catalysts and that there are regions which are kinetic and
diffusion controlled and diffusion–only controlled. Pt/Ta2O5–C catalysts exhibited
superior catalytic activity and stability compared Pt/Nb2O5–C, Pt/ZrO2–C and Pt/C. The
Pt/ZrO2–C exhibited the most inferior catalytic activity and stability. / Thesis (M.Sc. (Chemistry))--North-West University, Potchefstroom Campus, 2011.
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Solution-based synthesis and processing of nanocrystalline ZrB₂-based compositesXie, Yanli 24 November 2008 (has links)
Zirconium- and tantalum-based diborides, and diboride/carbide composites are of interest for ultra-high temperature applications requiring improved thermomechanical and thermochemical stability. This thesis focuses on the synthesis, processing and sintering of nanocrystalline powders with Zr- and Ta-based diboride/carbide/silicide compositions. A solution-based processing method was developed to prepare reactive mixtures that were precursors for ZrB₂-based powders. The precursors reacted to form the ceramic powders after suitable pyrolysis and borothermal/carbothermal reduction heat treatments. Single-phase ZrB₂ powders were prepared with initial composition of C/Zr = 4.8 and B/Zr = 3.0. ZrB₂-based composite powders with ZrC, ZrO₂, TaB₂, TaC, SiC, TaSi₂ and B₄C were prepared with particle sizes of 10-500 nm for different phases based SEM micrographs. The composite powders were highly sinterable with proper processing methods developed to avoid and remove oxide impurities. The relative densities of ZrB₂/B₄C, ZrB₂/TaB₂, ZrB₂/TaB₂/B4C, ZrB₂/TaSi₂ were in the range of 91%-97% after pressureless sintering at 2020 ℃
for 1 h or 30 min.
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A study on the material and device characteristics of hafnium oxynitride MOSFETs with TaN gate electrodesKang, Changseok, Lee, Jack Chung-Yeung, January 2004 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Jack C. Lee. Vita. Includes bibliographical references. Also available from UMI.
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