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CVD and ALD of Group IV- and V-Oxides for Dielectric ApplicationsForsgren, Katarina January 2001 (has links)
Due to the constantly decreasing dimensions of electronic devices, the conventional dielectric material in transistors and capacitors, SiO2, has to be replaced by a material with higher dielectric constant. Some of the most promising candidates are tantalum oxide,Ta2O5, zirconium oxide, ZrO2 and hafnium oxide, HfO2. This thesis describes new chemical vapour deposition (CVD) and atomic layer deposition (ALD) processes for deposition of Ta2O5, ZrO2 and HfO2 using the metal iodides as starting materials. The layer-by-layer growth in ALD was also studied in real time with a quartz crystal microbalance (QCM) to examine the process characteristics and to find suitable parameters for film deposition. All the processes presented here produced high-purity films at low deposition temperatures. It was also found that films deposited on Pt substrates generally crystallise at lower temperature, or with lower thickness, than on silicon and single-crystalline oxide substrates. Films grown on MgO(001) and α-Al2O3(001) substrates were strongly textured or epitaxial. For example, monoclinic HfO2 deposited on MgO(001) were epitaxial for deposition temperatures of 400-500 C in ALD and 500-600 C in CVD. Electrical characterisation showed that the crystallinity of the films had a strong effect on the dielectric constant, except in cases of very thin films, where the dielectric constant was more dependent on layer thickness.
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Investigation of Novel Metal Gate and High-κ Dielectric Materials for CMOS TechnologiesWestlinder, Jörgen January 2004 (has links)
The demands for faster, smaller, and less expensive electronic equipments are basically the driving forces for improving the speed and increasing the packing density of microelectronic components. Down-scaling of the devices is the principal method to realize these requests. For future CMOS devices, new materials are required in the transistor structure to enable further scaling and improve the transistor performance. This thesis focuses on novel metal gate and high-κ dielectric materials for future CMOS technologies. Specifically, TiN and ZrN gate electrode materials were studied with respect to work function and thermal stability. High work function, suitable for pMOS transistors, was extracted from both C-V and I-V measurements for PVD and ALD TiN in TiN/SiO2/Si MOS capacitor structures. ZrNx/SiO2/Si MOS capacitors exhibited n-type work function when the low-resistivity ZrNx was deposited at low nitrogen gas flow. Further, variable work function by 0.6 eV was achieved by reactive sputter depositing TiNx or ZrNx at various nitrogen gas flow. Both metal-nitride systems demonstrate a shift in work function after RTP annealing, which is discussed in terms of Fermi level pinning due to extrinsic interface states. Still, the materials are promising in a gate last process as well as show potential as complementary gate electrodes. The dielectric constant of as-deposited (Ta2O5)1-x(TiO2)x thin films is around 22, whereas that of AlN is about 10. The latter is not dependent on the degree of crystallinity or on the measurement frequency up to 10 GHz. Both dielectrics exhibit characteristics appropriate for integrated capacitors. Finally, utilization of novel materials were demonstrated in strained SiGe surface-channel pMOSFETs with an ALD TiN/Al2O3 gate stack. The transistors were characterized with standard I-V, charge pumping, and low-frequency noise measurements. Correlation between the mobility and the oxide charge was found. Improved transistor performance was achieved by conducting low-temperature water vapor annealing, which reduced the negative charge in the Al2O3.
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Lead Determination By Flame Atomic Absorption Spectrometry Using A Slotted Quartz Tube Atom Trap And Metal CoatingsDemirtas, Ilknur 01 July 2009 (has links) (PDF)
Flame Atomic Absorption Spectrometry (FAAS) still keeps its importance despite the relatively low sensitivity / because it is a simple and economical technique for determination of metals. In recent years atom traps have been developed to increase the sensitivity of FAAS. Although the detection limit of FAAS is only at the level of mg/L, with the use of atom traps it can reach to ng/mL. Slotted quartz tube (SQT) is one of these atom traps, it is applied for determination of volatile elements / it is economical, commercially available and easy to use. In this study, a sensitive analytical method has been developed for the determination of lead with the help of SQT. Regarding the angle between the two slots of SQT, 120° / and 180° / configurations were used and the results were compared. There were three modes of SQT used. The first application was for providing longer residence time of analyte atoms in the measurement zone / 3 fold sensitivity enhancement was observed. The second mode was the usage of SQT for preconcentration of lead atoms. In the presence of a lean air-acetylene flame, analyte atoms were trapped in the inner surface of SQT for a few minutes. Then, by the help of a small volume (10-50 & / #956 / L) of Methyl isobutyl ketone (MIBK), analyte atoms were revolatilized and a rapid atomization took place. Using this mode, a sensitivity enhancement of 574 was obtained at a rather low (3.9 mL/min) suction rate / 1320 fold
improvement was reached at higher sample suction rate (7.4 mL/min) for 5.0 min collection. The last mode involves coating of the inner surface of SQT with several kinds of transition metals. The best sensitivity enhancement, 1650 fold, was obtained by the Ta coated SQT. In addition, effects of some elements and anions on Pb signal in Tacoated-SQT-AT-FAAS were examined. Final step consists of surface analysis / chemical nature of Pb trapped on quartz and Ta surface, and the chemical nature of Ta on quartz surface were investigated by X-ray Photoelectron Spectroscopy (XPS) and Raman Spectroscopy.
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Tellurium Determination By Flame Atomic Absorption Spectrometry Using A Slotted Quartz Tube Atom Trap And Metal CoatingsOsmanbasoglu, Mahmut 01 February 2011 (has links) (PDF)
Flame Atomic Absorption Spectroscopy (FAAS) has lover sensitivity than similar analytical methods, however it has an important place for analysis due to its easy application and economic practicability especially in metal determinations. In order to increase the sensitivity of FAAS from mg/L level to ng/L level, various atom trap systems have been used. One of these atom traps, Slotted Quartz Tube (SQT), which is easy, economical and useful for volatile element determination, is used in this study as a sensitive analytical method for determination of tellurium. In the study, determination of Te by SQT is handled in three different modules. First, only with SQT itself, longer residence time for Te atoms in the measurement zone is provided and consequently 3.2 fold sensitivity enhancement is obtained both for Te (VI) and Te (IV). In the second module, SQT is used for concentration of tellurium species in a lean flame by sending the analyte into SQT for a definite time and trapping them on the inner surface of the SQT. After trapping the analyte, in order to determine the Te concentration, a small volume (10-50 µ / L) of organic solvent such as methyl ethyl ketone (MEK) is introduced to the flame for revolatilization and a rapid atomization of Te on the surface is provided. In this trapping method, for 5 minutes collection with a 6 mL/min suction rate, 143 fold enhancement for Te (VI) and 142 fold enhancement for Te (IV) were obtained. In the third module, different from the second one, the inner surface of the SQT is coated with different metals for increasing the amount of Te trapped on the surface and the best enhancement for tellurium is obtained with Tantalum-coated SQT with 252 fold enhancement for Te (VI) and 246 fold enhancements for Te (IV). All improvements are calculated according to the signals obtained in FAAS method. Separate calibration plots were used for Te (IV) and Te (VI).
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Separation of tantalum and niobium by solvent extraction / M.J. Ungerer.Ungerer, Maria Johanna January 2012 (has links)
Niobium (Nb) and tantalum (Ta) are found in the same group (VB) of the periodic table of elements and therefore have similar chemical properties, which is the reason why they are difficult to separate. They are usually found together in various minerals of which the most important are columbite ((Fe, Mn, Mg)(Nb, Ta)2O6) and tantalite ((Fe, Mn)(Nb, Ta)2O6).
Several methods have been used to separate Nb and Ta. Most methods use very high concentrations of hydrofluoric acid (HF) and sulphuric acid (H2SO4) as the aqueous phase, tributyl phosphate (TBP) as the extractant and methyl isobutyl ketone (MIBK) as the organic phase. High extraction can be achieved, but the reagents used are hazardous. With the increasing demand of both pure Ta and Nb, as well as stricter environmental requirements, a need exists to develop a more efficient and safer technique to separate Ta and Nb.
In this project the focus was on the solvent extraction (SX) of Ta and Nb with the possible application in a membrane-based solvent extraction (MBSX) process. For this purpose, eight different extractants were investigated, namely the cation exchangers di-iso-octyl-phosphinic acid (PA) and di-(2-ethylhexyl)-phosphoric acid (D2EHPA), the neutral solvating extractant 2-thenoyl-trifluoro- acetone (TTA), and the anion exchangers Alamine 336, Aliquat 336, 1-octanol, 2-octanol and 3-octanol. The extractant to metal ratio was varied from 0.1:1 to 10:1, while cyclohexane was used as diluent and 3% v/v 1-octanol was used as modifier for the organic phase. In addition, four different acids, hydrochloric acid (HCl), nitric acid (HNO3), sulphuric (H2SO4) and perchloric acid (HClO4), were used at different concentrations to determine the best combination for extraction.
First, fluoride salts of Ta and Nb (Ta(Nb)F5) were tested and the optimum results showed that the highest extraction was obtained with PA and D2EHPA, irrespective of the type of acid used. Similarly, irrespective of the acid used, extraction with PA and D2EHPA increased with increasing acid concentration, followed by Alamine 336, Aliquat 336 and then TTA and the octanols. Extraction values of 97% Ta at 15 mol/dm3 and 85% Nb between 12 and 15 mol/dm3 were obtained. Although extraction of both Ta and Nb was achieved with all the acids tested, only H2SO4 showed sufficient separation (log D = 3) of the two metals in the 0 to 2 mol/dm3 acid range and 15 mol/dm3 for PA and D2EHPA, respectively. Precipitation, probably due to hydrolysis of the metals, occurred in the absence of acid when using Alamine 336, Aliquat 336 and TTA. The octanols showed the least amount of extraction of Ta and Nb, irrespective of the acid investigated. The optimum extraction was achieved with an E/M ratio of 3:1 of PA and D2EHPA as the extractant and 10 mol/dm3 H2SO4 in the aqueous phase.
The NH4Ta(Nb)F6 salt solution was investigated using the optimum conditions for maximum extraction obtained from the Ta(Nb)F5 experiments, i.e. 4 mol/dm3 H2SO4 with an E/M ratio above 3:1 for the extractant PA and 4 mol/dm3 H2SO4 with an E/M ratio of 20:1 for the extractant D2EHPA. Kinetic equilibrium for PA was reached after 10 minutes and for D2EHPA after 20 minutes. The highest extraction of Ta (100%) above 3 mol/dm3 H2SO4 and Nb (54%) at 8 mol/dm3 with the highest separation factor of 4.7 with PA was achieved, followed by the 100% extraction of Ta above 5 mol/dm3 and 40% Nb at 10 mol/dm3 with the highest separation factor of 4.9 in D2EHPA. Although the aim of this study was the extraction and separation of Ta and Nb, the recovery or back extraction of the metals from the organic phase, as well as the membrane-based solvent extraction (MBSX) was briefly investigated. From the preliminary results obtained it became apparent that further research into the different aspects, including the type of stripping agent used, stripping agent concentration, effect of Ta to Nb ratio and different sources of Ta and Nb is needed to obtain the optimum conditions for the MBSX process and the subsequent recovery of Ta and Nb. / Thesis (MSc (Chemistry))--North-West University, Potchefstroom Campus, 2013.
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Separation of tantalum and niobium by solvent extraction / M.J. Ungerer.Ungerer, Maria Johanna January 2012 (has links)
Niobium (Nb) and tantalum (Ta) are found in the same group (VB) of the periodic table of elements and therefore have similar chemical properties, which is the reason why they are difficult to separate. They are usually found together in various minerals of which the most important are columbite ((Fe, Mn, Mg)(Nb, Ta)2O6) and tantalite ((Fe, Mn)(Nb, Ta)2O6).
Several methods have been used to separate Nb and Ta. Most methods use very high concentrations of hydrofluoric acid (HF) and sulphuric acid (H2SO4) as the aqueous phase, tributyl phosphate (TBP) as the extractant and methyl isobutyl ketone (MIBK) as the organic phase. High extraction can be achieved, but the reagents used are hazardous. With the increasing demand of both pure Ta and Nb, as well as stricter environmental requirements, a need exists to develop a more efficient and safer technique to separate Ta and Nb.
In this project the focus was on the solvent extraction (SX) of Ta and Nb with the possible application in a membrane-based solvent extraction (MBSX) process. For this purpose, eight different extractants were investigated, namely the cation exchangers di-iso-octyl-phosphinic acid (PA) and di-(2-ethylhexyl)-phosphoric acid (D2EHPA), the neutral solvating extractant 2-thenoyl-trifluoro- acetone (TTA), and the anion exchangers Alamine 336, Aliquat 336, 1-octanol, 2-octanol and 3-octanol. The extractant to metal ratio was varied from 0.1:1 to 10:1, while cyclohexane was used as diluent and 3% v/v 1-octanol was used as modifier for the organic phase. In addition, four different acids, hydrochloric acid (HCl), nitric acid (HNO3), sulphuric (H2SO4) and perchloric acid (HClO4), were used at different concentrations to determine the best combination for extraction.
First, fluoride salts of Ta and Nb (Ta(Nb)F5) were tested and the optimum results showed that the highest extraction was obtained with PA and D2EHPA, irrespective of the type of acid used. Similarly, irrespective of the acid used, extraction with PA and D2EHPA increased with increasing acid concentration, followed by Alamine 336, Aliquat 336 and then TTA and the octanols. Extraction values of 97% Ta at 15 mol/dm3 and 85% Nb between 12 and 15 mol/dm3 were obtained. Although extraction of both Ta and Nb was achieved with all the acids tested, only H2SO4 showed sufficient separation (log D = 3) of the two metals in the 0 to 2 mol/dm3 acid range and 15 mol/dm3 for PA and D2EHPA, respectively. Precipitation, probably due to hydrolysis of the metals, occurred in the absence of acid when using Alamine 336, Aliquat 336 and TTA. The octanols showed the least amount of extraction of Ta and Nb, irrespective of the acid investigated. The optimum extraction was achieved with an E/M ratio of 3:1 of PA and D2EHPA as the extractant and 10 mol/dm3 H2SO4 in the aqueous phase.
The NH4Ta(Nb)F6 salt solution was investigated using the optimum conditions for maximum extraction obtained from the Ta(Nb)F5 experiments, i.e. 4 mol/dm3 H2SO4 with an E/M ratio above 3:1 for the extractant PA and 4 mol/dm3 H2SO4 with an E/M ratio of 20:1 for the extractant D2EHPA. Kinetic equilibrium for PA was reached after 10 minutes and for D2EHPA after 20 minutes. The highest extraction of Ta (100%) above 3 mol/dm3 H2SO4 and Nb (54%) at 8 mol/dm3 with the highest separation factor of 4.7 with PA was achieved, followed by the 100% extraction of Ta above 5 mol/dm3 and 40% Nb at 10 mol/dm3 with the highest separation factor of 4.9 in D2EHPA. Although the aim of this study was the extraction and separation of Ta and Nb, the recovery or back extraction of the metals from the organic phase, as well as the membrane-based solvent extraction (MBSX) was briefly investigated. From the preliminary results obtained it became apparent that further research into the different aspects, including the type of stripping agent used, stripping agent concentration, effect of Ta to Nb ratio and different sources of Ta and Nb is needed to obtain the optimum conditions for the MBSX process and the subsequent recovery of Ta and Nb. / Thesis (MSc (Chemistry))--North-West University, Potchefstroom Campus, 2013.
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A critique of the environmental impact assessment procedure in Thailand /Tongcumpou, Chantra. January 1991 (has links) (PDF)
Thesis (M. Env. St.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1992. / Includes bibliographical references (leaves 61-65).
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Desenvolvimento e caracteriza??o de um comp?sito matriz met?lica (CMM): a?o EUROFER97 refor?ado com Carbeto de T?ntalo - TaCOliveira, Leiliane Alves de 17 May 2013 (has links)
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Previous issue date: 2013-05-17 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Steel is an alloy EUROFER promising for use in nuclear reactors, or in applications where the material is subjected to temperatures up to 550 ? C due to their lower creep resistance under. One way to increase this property, so that the steel work at higher temperatures it is necessary to prevent sliding of its grain boundaries. Factors that influence this slip contours are the morphology of the grains, the angle and speed of the grain boundaries. This speed can be decreased in the presence of a dispersed phase in the material, provided it is fine and homogeneously distributed. In this context, this paper presents the development of a new material metal matrix composite (MMC) which has as starting materials as stainless steel EUROFER 97, and two different kinds of tantalum carbide - TaC, one with average crystallite sizes 13.78 nm synthesized in UFRN and another with 40.66 nm supplied by Aldrich. In order to improve the mechanical properties of metal matrix was added by powder metallurgy, nano-sized particles of the two types of TaC. This paper discusses the effect of dispersion of carbides in the microstructure of sintered parts. Pure steel powders with the addition of 3% TaC UFRN and 3% TaC commercial respectively, were ground in grinding times following: a) 5 hours in the planetary mill for all post b) 8 hours of grinding in the mill Planetary only for steel TaC powders of commercial and c) 24 hours in the conventional ball mill mixing the pure steel milled for 5 hours in the planetary mill with 3% TaC commercial. Each of the resulting particulate samples were cold compacted under a uniaxial pressure of 600MPa, on a cylindrical matrix of 5 mm diameter. Subsequently, the compressed were sintered in a vacuum furnace at temperatures of 1150 to 1250 ? C with an increment of 20 ? C and 10 ? C per minute and maintained at these isotherms for 30, 60 and 120 minutes and cooled to room temperature. The distribution, size and dispersion of steel and composite particles were determined by x-ray diffraction, scanning electron microscopy followed by chemical analysis (EDS). The structures of the sintered bodies were observed by optical microscopy and scanning electron accompanied by EDS beyond the x-ray diffraction. Initial studies sintering the obtained steel EUROFER 97 a positive reply in relation to improvement of the mechanical properties independent of the processing, because it is obtained with sintered microhardness values close to and even greater than 100% of the value obtained for the HV 333.2 pure steel as received in the form of a bar / O a?o EUROFER ? uma liga promissora para utiliza??o em reatores nucleares, ou em aplica??es onde o material ? submetido a temperaturas de servi?o at? 550?C devido sua menor resist?ncia sob flu?ncia. Uma forma de aumentar essa propriedade, para que o a?o trabalhe a temperaturas mais altas ? necess?rio impedir o deslizamento de seus contornos de gr?o. Fatores que influenciam nesse deslizamento dos contornos s?o a morfologia dos gr?os, o ?ngulo e a velocidade dos contornos de gr?o. Esta velocidade pode ser diminu?da com a presen?a de uma fase dispersa no material, desde que seja fina e distribu?da de forma homog?nea. Neste contexto, este trabalho apresenta o desenvolvimento de um novo material Comp?sito de Matriz Met?lica (CMM), que tem como materiais de partida o a?o inoxid?vel EUROFER 97; e dois tipos diferentes de Carbeto de T?ntalo TaC, um com tamanhos m?dios de cristalitos de 13,78 nm sintetizado na UFRN e outro com 40,66 nm fornecido pela Aldrich. Objetivando melhorar as propriedades mec?nicas da matriz met?lica foi adicionado, atrav?s da metalurgia do p?, part?culas nanom?tricas desses dois tipos de TaC. Este trabalho discute o efeito da dispers?o desses carbetos na microestrutura das pe?as sinterizadas. P?s de a?o puro, com adi??o de 3% de TaC UFRN e 3% de TaC comercial respectivamente, foram mo?dos nos seguintes tempos de moagem: a) 5 horas, no moinho planet?rio para todos os p?s; b) 8 horas de moagem no moinho planet?rio somente para os p?s de a?o com TaC comercial; e c) 24 horas no moinho convencional de bolas da mistura do a?o puro mo?do durante 5 horas no moinho planet?rio com 3% de TaC comercial. Cada uma das amostras particuladas resultantes foram compactadas a frio sob uma press?o uniaxial de 600MPa, em uma matriz cil?ndrica de 5 mm de di?metro. Posteriormente, os compactados foram sinterizadas em forno a v?cuo, em temperaturas de 1150 e 1250? C com incremento de 20 ?C e 10?C por minuto, sendo mantidas nestas isotermas por 30, 60 e 120 minutos e resfriadas ? temperatura ambiente. A distribui??o, tamanho e dispers?o dos a?os e comp?sitos particulados foram determinadas por difra??o de raios x, microscopia eletr?nica de varredura seguida de uma an?lise qu?mica (EDS). As estruturas dos corpos sinterizados foram observadas por microscopia ?tica e eletr?nica de varredura acompanhada de EDS al?m da difra??o de raios x. Os estudos iniciais de sinteriza??o com o a?o EUROFER 97 obteve uma resposta positiva em rela??o a melhoria das propriedades mec?nicas independente do processamento, pois se obteve sinterizados com valores de microdureza pr?ximo e at? maior que 100% do valor de 333,2 HV obtidos para o a?o puro como recebido, em forma de barra
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Obten??o de p?s de t?ntalo met?lico a partir da redu??o aluminot?rmica com igni??o a plasmaBrito, Roseane Aparecida de 26 March 2007 (has links)
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Previous issue date: 2007-03-26 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Metallic tantalum has a high commercial value due to intrinsic properties like excellent ductility, corrosion resistance, high melt and boiling points and good electrical and thermal conductivities. Nowadays, it is mostly used in the manufacture of capacitors, due to excellent dielectric properties of its oxides. In the nature, tantalum occurs in the form of oxide and it is extracted mainly from tantalite-columbite ores. The tantalum is usually produced by the reduction of its oxide, using reductants like carbon, silicon, calcium, magnesium and aluminum. Among these techniques, the aluminothermic reduction has been used as the industrial method to produce niobium, tantalum and their alloys, due to the easy removal of the Al and Al2O3 of the system, easing further refining. In conventional aluminothermic reduction an electrical resistance is used to trigger the reaction. This reaction self-propagates for all the volume of material. In this work, we have developed a novel technique of aluminothermic reduction that uses the hydrogen plasma to trigger the reaction. The results obtained by XRD, SEM and EDS show that is possible to obtain a compound rich in tantalum through this technique of aluminothermic reduction in the plasma reactor / O t?ntalo ? um metal de elevado valor comercial devido suas propriedades intr?nsecas como excelente ductilidade, resist?ncia ? corros?o, elevados pontos de fus?o e ebuli??o e boas condutividades t?rmica e el?trica. Atualmente sua maior aplica??o tem sido na produ??o de capacitores, devido ?s excelentes propriedades diel?tricas de seus ?xidos. Na natureza o t?ntalo ocorre na forma de ?xido e ? extra?do principalmente do min?rio tantalita-columbita. O p? de t?ntalo met?lico ? normalmente produzido pela redu??o do seu ?xido, utilizando agentes redutores tais como carbono, sil?cio, c?lcio, magn?sio e o alum?nio. Dentre estas t?cnicas, a aluminotermia vem sendo utilizada como m?todo industrial para a produ??o do ni?bio, t?ntalo e suas ligas, em virtude da f?cil remo??o do alum?nio (Al) e da alumina (Al2O3) do sistema, o que facilita a etapa de refino. No processo de aluminotermia convencional ? utilizado um elemento resistivo como ignitor da rea??o, que se auto-propaga para todo o volume de material. No presente trabalho foi desenvolvida uma t?cnica de aluminotermia que utiliza o plasma de hidrog?nio como ignitor da rea??o. Os resultados obtidos por DRX, MEV e EDS mostram que ? poss?vel a obten??o de um concentrado rico em t?ntalo pela t?cnica de redu??o aluminot?rmica a plasma
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Development of a high temperature sensor suitable for post-processed integration with electronicsTabasnikov, Aleksandr January 2018 (has links)
Integration of sensors and silicon-based electronics for harsh environment applications is driven by the automotive industry and the maturity of semiconductor processes that allow embedding sensitive elements onto the same chip without sacrificing the performance and integrity of the electronics. Sensor devices post-processed on top of electronics by surface micromachining allow the addition of extra functionality to the fabricated ICs and creating a sensor system without significant compromise of performance. Smart sensors comprised of sensing structures integrated with silicon carbide-based electronics are receiving attention from more industries, such as aerospace, defense and energy, due to their ability to operate in very demanding conditions. This thesis describes the design and implementation of a novel, integrated thin film temperature sensor that uses a half-bridge arrangement to measure thin film platinum sensitive elements. Processes have been developed to fabricate temperature insensitive thin film tantalum nitride resistors which can be combined with the platinum elements to form the temperature transducing bridge. This circuit was designed to be integrated with an existing silicon carbide-based instrumentation amplifier by post-CMOS processing and to be initially connected to the bond pads of the amplifier input and output ports. Thin films fabricated using the developed TaN and Pt processes have been characterized using resistive test structures and crystallographic measurements of blanket thin film layer samples, and the relationship between the measurement results obtained has been analyzed. An initial demonstration of temperature sensing was performed using tantalum nitride and platinum thin film resistor element chips which were fabricated on passivated silicon substrates and bonded into high temperature packages. The bridge circuit was implemented by external connections through a printed circuit board and the bridge output was connected to a discrete instrumentation amplifier to mimic the integrated amplifier. The temperature response of the circuit measured at the output of the amplifier was found to have sensitivity of 844 μV·°C–1 over the temperature range of 25 to 100 °C. Two integrated microfabrication process flows were evaluated in this work. The initial process provided a very low yield for contact resistance structures between TaN and Pt layers, which highlighted problems with the thin film platinum deposition process. Multiple improvement options have been identified among which removal of the dielectric layer separating TaN and Pt layers and thicker Pt film were considered and a redesign of both layout and the process flow has resulted in improved yield of platinum features produced directly on top of TaN features. Temperature sensitivity of the integrated sensor devices was found to depend significantly on parasitic elements produced by thin film platinum step coverage, the values of which were measured by a set of resistive test structures. A new microfabrication design has enabled the production of a group of integrated temperature sensors that had a sensitivity of 150.84 μV·°C–1 in the temperature range between 25 and 200 °C on one of the fabricated wafers while the best fabricated batch of sensors had a sensitivity of 1079.2 μV·°C–1.
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