This study is to develop the manufacturing processes of thin film bulk acoustic device by MEMS technology, including lithography, wet etching, dry etching and rf Magnetron sputtering.LPCVD is used to deposit SiNx as the membranes and mask for etching of silicon wafer. The electrodes of molybdenum metal (Mo) and piezoelectric layer of aluminum nitride (AlN) on top side are prepared by dc and rf sputtering,respectively. The acoustic cavity on back side is achieved by 30%wt 100¢J KOH solution and reactive ion etching (RIE). In this study, the crystallography of the coated films was analyzed by X-ray diffraction. The surface and cross-sectional morphologies of AlN films were investigated by electron microscope. The piezoelectric layer of AlN thin film prepared by rf magnetron sputtering shows the highly c-axis preferred orientation and fine morphology under the optimal sputtering parameters of rf power of 200W, sputtering pressure of 3 mTorr, substrate temperature of 400¢J and nitrogen concentration of 25%. The frequency responses of fabricated FBAR devices are evaluated using the Hewlett-Packard 8720-ET network analyzer. Moreover, the optimal thickness of 1500Å SiNx film prepared by LPCVD revealed the excellent masking effect and non-stress for membrane. The yield for the fabrication of acoustic cavity is maximum of 85% can be achieved by using the combined etching steps of wet and dry etching.

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Nos últimos anos tem se dado uma evolução muito grande na área industrial de MEMS, e esta se caracteriza por desenvolvimento dos processos de microeletrônica para diminuição de custos e a própria integração de diferentes sistemas que passam a ser muito confiáveis em diferentes aplicações. Motivado pelas tendências de elevar os conhecimentos de processos para obtenção de MEMS, foi proposto um trabalho de corrosão anisotrópica de silício utilizando solução de hidróxido de potássio (KOH) junto com a adição de sais metálicos. O objetivo é comprovar o efeito de compensação cinética da reação e a influência destes metais no caráter anisotrópico e nas taxas de corrosão. Foi analisado o efeito de zinco, alumínio e cobre, e puderam ser observadas alterações nas taxas de corrosão e, conseqüentemente, nas geometrias resultantes no corpo de silício. Com a caracterização dessas mudanças comprovou-se suposições anteriores de que o efeito de compensação cinética encontrado na síntese direta de dimetilclorosilana (DMDCS) e silício, também ocorreria para a corrosão de silício em KOH, pois esses processos obedecem a lei de Arrhenius e tem um comportamento anisotrópico em silício. Os resultados obtidos, graças a um grande detalhamento de todos as etapas de processo e caracterização voltada à tecnologia do silício, comprovaram as suposições teóricas e mostraram como pode ser modificada a taxa de corrosão na anisotropia com a adição de metais em solução. / In the past few years it has been a huge evolution in industrial area of MEMS, and this one is characterized by the development of the processes of microelectronic to reduce cost and to integrate different systems that become very trustful in different applications. It is being done a work in silicon anisotropic etching in Potassium hydroxide (KOH) added with metallic impurities aiming the study of the kinetic compensation effect and the influence of these metals in the anisotropy and in etch rates. It was analyzed the effects of Zinc, Aluminum and Cupper and it could be observed changes in etch rates, and, consequently, in the resulting geometries. After characterization of theses changes it was proved that previous suppositions that the kinetic compensation effects found in direct synthesis of dimethyldichorosilane (DMDCS) and silicon would also occur for silicon anisotropic etching in KOH, due to both reactions follows Arrhenius law and are anisotropic reactions. The obtained results proved the theory suppositions that the etch rate and anisotropy can be modified when adding metals to the solution.

In this thesis, we study high quality InN films grown on sapphire (0001) by plasma-assisted molecular beam epitaxy (PAMBE). We used double layers methods to reduce lattice mismatch successfully. In this experiment, we have two series of samples, about series of A use low temperature GaN (LT-GaN) as the buffer layer as compared with series of B use high temperature AlN (HT-AlN) as the buffer layer. By in situ reflection high-energy electron diffraction (RHEED), we got film¡¦s surface situation. Surface morphology of the samples was observed by atomic force microscope (AFM). By high resolution X-ray diffraction (HR-XRD) methods was analyzed quality and composition of InN films. Van der Pauw method (Hall) was used to determine carrier concentration and mobility. The optical properties of InN films under different growth conditions were investigated by photoluminescence (PL). By changing growth temperature of these samples, we found the series of A having some fine characters as the InN(0002) rocking curve was 343 arcsec and InN(10-12) rocking curve was nearly 1000 arcsec. The mobility and carrier density of these samples were approximately 1000 cm2/Vs and 3 x 1018 cm-3 by Van der Pauw method.

Nos últimos anos tem se dado uma evolução muito grande na área industrial de MEMS, e esta se caracteriza por desenvolvimento dos processos de microeletrônica para diminuição de custos e a própria integração de diferentes sistemas que passam a ser muito confiáveis em diferentes aplicações. Motivado pelas tendências de elevar os conhecimentos de processos para obtenção de MEMS, foi proposto um trabalho de corrosão anisotrópica de silício utilizando solução de hidróxido de potássio (KOH) junto com a adição de sais metálicos. O objetivo é comprovar o efeito de compensação cinética da reação e a influência destes metais no caráter anisotrópico e nas taxas de corrosão. Foi analisado o efeito de zinco, alumínio e cobre, e puderam ser observadas alterações nas taxas de corrosão e, conseqüentemente, nas geometrias resultantes no corpo de silício. Com a caracterização dessas mudanças comprovou-se suposições anteriores de que o efeito de compensação cinética encontrado na síntese direta de dimetilclorosilana (DMDCS) e silício, também ocorreria para a corrosão de silício em KOH, pois esses processos obedecem a lei de Arrhenius e tem um comportamento anisotrópico em silício. Os resultados obtidos, graças a um grande detalhamento de todos as etapas de processo e caracterização voltada à tecnologia do silício, comprovaram as suposições teóricas e mostraram como pode ser modificada a taxa de corrosão na anisotropia com a adição de metais em solução. / In the past few years it has been a huge evolution in industrial area of MEMS, and this one is characterized by the development of the processes of microelectronic to reduce cost and to integrate different systems that become very trustful in different applications. It is being done a work in silicon anisotropic etching in Potassium hydroxide (KOH) added with metallic impurities aiming the study of the kinetic compensation effect and the influence of these metals in the anisotropy and in etch rates. It was analyzed the effects of Zinc, Aluminum and Cupper and it could be observed changes in etch rates, and, consequently, in the resulting geometries. After characterization of theses changes it was proved that previous suppositions that the kinetic compensation effects found in direct synthesis of dimethyldichorosilane (DMDCS) and silicon would also occur for silicon anisotropic etching in KOH, due to both reactions follows Arrhenius law and are anisotropic reactions. The obtained results proved the theory suppositions that the etch rate and anisotropy can be modified when adding metals to the solution.

The popular tourist destination island of Koh Phi Phi Don, Thailand was heavily affected by the Indian Ocean Tsunami in December 2004, which resulted in a destroyed tourism infrastructure and complete downturn of tourism. Extensive recovery and rebuilding work by emerging community groups, returned locals, international volunteers and Thai government units provided an efficient but hasty reconstruction of the destination. Ethnographic research conducted in the community provided insights into the complex stakeholder interactions and their roles and influences on the reconstruction of the community. The community�s level of vulnerability on Koh Phi Phi Don was influenced by social processes and interactions during the destination�s recovery process as the various stakeholders (e.g. government vs. locals) had differing perceptions of the island�s economic, environmental and social vulnerability. These disputes are grounded in different social time processes, particularly illustrated through land law disputes among locals, landowners and the government. Other factors which influenced the reconstruction of Koh Phi Phi as a tourist destination were pre-tsunami conditions (past overdevelopment), the empowerment of the community, the reconstructed place identity, various anniversary celebrations and the early warning system. A model is suggested to illustrate and discuss Koh Phi Phi Don as a disaster destination, which provides insights into the dynamics which govern a destination�s post-disaster recovery period. Thus, it illustrates how stakeholder interaction is influenced by distinct understandings of the multiple notions of vulnerability. Furthermore, this study establishes essential links between disaster and tourism theories and suggests an extended tourism disaster management framework, which calls for an inclusion of post-recovery processes.

Ethylene oxide (EO) is a very versatile compound with considerable energy in its ring structure. Its reactions proceed mainly via ring opening and are highly exothermic. Under some conditions, it is known to undergo a variety of reactions, such as isomerization, polymerization, hydrolysis, combustion and decomposition Due to its very reactive characteristic and widely industrial applications, EO has been involved in a number of serious incidents such as Doe Run 1962, Freeport 1974, Deer Park 1988 and Union Carbide Corporation’s Seadrift 1991. The impacts can be severe in terms of death and injury to people, damage to physical property and effects on the environment. For instance, the Union Carbide incident in 1991 caused one fatality and extensive damage to the plant with the property damage of up to 80 million dollars. Contamination has a considerable impact on EO reactivity by accelerating substantially its decomposition and playing a key role on EO incidents. In this work, the reactivity of EO with contaminants such as KOH, NaOH, NH4OH, and EDTA is evaluated. Useful information that is critical to the design and operation of safer chemical plant processes was generated such as safe storage temperatures (onset temperature), maximum temperature, maximum pressure, temperature vs. time, heat and pressure generation rates as a function of temperature and time to maximum rate using adiabatic calorimetry. A special arrangement for the filling-up of the cell was constructed due to the gaseous nature and toxicity of EO. A comparison of their thermal behavior is also presented since several contaminants are studied.

A simple and high efficient wet etching technique for fabricating pyramid textures on (100) Si wafer is proposed. Conventionally, pyramid textures were formed on Si wafers to reduce reflections using KOH anisotropic etching. Isopropyl Alcohol (IPA) is often added to the solution to abate the bubbling effect caused by hydrogen released form the Si surfaces during reaction. In this study, a metal net with proper opening dimension was used as a shelter to trap the hydrogen from leaving the surfaces of Si, and therefore turns the hydrogen gas into a gas-type etching mask during the anisotropic etching. In this way, pyramid textures with dimensions range from 3µm to 8µm were successfully fabricated. The measured average reflectivity of the texture for incident optical wave length from 400nm to 1000nm is less than 18%.

The popular tourist destination island of Koh Phi Phi Don, Thailand was heavily affected by the Indian Ocean Tsunami in December 2004, which resulted in a destroyed tourism infrastructure and complete downturn of tourism. Extensive recovery and rebuilding work by emerging community groups, returned locals, international volunteers and Thai government units provided an efficient but hasty reconstruction of the destination. Ethnographic research conducted in the community provided insights into the complex stakeholder interactions and their roles and influences on the reconstruction of the community. The community�s level of vulnerability on Koh Phi Phi Don was influenced by social processes and interactions during the destination�s recovery process as the various stakeholders (e.g. government vs. locals) had differing perceptions of the island�s economic, environmental and social vulnerability. These disputes are grounded in different social time processes, particularly illustrated through land law disputes among locals, landowners and the government. Other factors which influenced the reconstruction of Koh Phi Phi as a tourist destination were pre-tsunami conditions (past overdevelopment), the empowerment of the community, the reconstructed place identity, various anniversary celebrations and the early warning system. A model is suggested to illustrate and discuss Koh Phi Phi Don as a disaster destination, which provides insights into the dynamics which govern a destination�s post-disaster recovery period. Thus, it illustrates how stakeholder interaction is influenced by distinct understandings of the multiple notions of vulnerability. Furthermore, this study establishes essential links between disaster and tourism theories and suggests an extended tourism disaster management framework, which calls for an inclusion of post-recovery processes.

Microfabricated needles have the potential for inexpensive drug delivery without pain. The ability to deliver medication painlessly to patients will someday be not just hoped for but expected by the general public. The commercialization of this technology will also lead to other valuable technologies, such as systems that continually monitor and control insulin or other drugs in diabetic patients. This research presents fabrication procedures developed to produce pyramidal-shaped microneedles with microchannels that will allow for fluid delivery. The microchannels are etched into the substrate surface of a [100] silicon wafer using inductively coupled plasma etching. After the channel etch a layer of silicon nitride is deposited onto the inner walls of the microchannels and on the surface of the substrate. The nitride on the substrate surface provides the hard mask necessary to etch the microneedles, which are wet etched in a bath of potassium hydroxide (KOH). The selectivity of the KOH on [100] silicon is such that octagonal shaped pyramids are etched into the surface of the wafer. The pyramids are aligned with the previously etched microchannels to allow for needles with channels running through them. This research presents the first needles demonstrated with drug delivery channels running through the robust pyramidal needle shape. In addition to the microchannel/microneedle fabrication procedure, microchannels were developed with inner structures as a method of creating hydrophobic surfaces on the inner walls of the channels. It was found that the channels developed had far too much variability in the diameter to accurately create a measurable reduction in flow; however, a loss coefficient was calculated showing increased flow rates in hydrophobically coated microchannels when hydrophobic structures are incorporated into the channel design. It was also discovered that a hydrophobic coating, typically used to increase flow rates through a channel, can impede flow rate. There was no evidence found to suggest that hydrophobically coated microchannels of this size, with or without structures, will yield higher flow rates than non-coated microchannels.