Rapid Thermal Processing and its Effects on High Aspect Ratio Silicon Features

Silicon (Si) is the most widely used material in semiconductor devices fabrication, and silicon wafers undergo many steps before achieving the final product, including heat treatments. A rapid thermal processor, with a base pressure of 10-6 mbar, is the case study of this work, and it’s proposed as an alternative to more conventional furnace methods. Moreover, the main goal was to investigate the impact rapid thermal processing (RTP) has on different high aspect ratio (HAR) structures etched into Si substrates. The ‘clear – oxidize – remove – etch’ (CORE) process was used as the primary etching process, resorting to a deep reactive ion etching (DRIE) tool. The structural characterization was mainly carried out by scanning electron microscopy, although ellipsometry has also been used. RTP refers to any process that implies elevating the temperature of a given material, mainly semiconductors, to high values during short periods (minutes or even less). As such, it can be used as a multi-functional and versatile microfabrication tool, capable of performing rapid thermal oxidation, hydrogenation, annealing and nitridation, among others. The project focused on the first three, which led to several experimental studies. According to the results, the atom migration phenomenon was witnessed in both 5% hydrogen/argon-ambient and argon-ambient rapid thermal annealing (RTA). Thus, it resulted in either three-dimensional (3D) profile transformation or silicon-on-nothing (SON) structures due to empty-space-in-silicon (ESS) formation. However, silicon volume loss was reported, possibly caused by sublimation and etching by reaction with oxygen (O2). Furthermore, the tool was able to grow uniform silicon oxide (SiO2) thin films –below 17 nm and 20 nm for Si (100) and Si (110) surfaces, respectively. The removal of previously grown black silicon (BSi) was also accomplished by RTA, with some margin for improvement. In general, a better understanding of these techniques will allow for their insertion, for instance, into the metal-oxide-semiconductor (MOS) and micro-electromechanical systems (MEMS) devices manufacturing process and the large scale integrated circuits world.Mundialmente, o silício (Si) é dos materiais mais utilizados na indústria de dispositivos semicondutores, sendo que um substrato pode ser submetido a vários processos até ser atingido um produto final, incluindo tratamentos térmicos. Neste trabalho, um processador térmico de rápido aquecimento - pressão base de 10-6 mbar - é estudado e proposto como alternativa à utilização de fornos convencionais. Assim, o principal objetivo é investigar o impacte que processamentos térmicos de curta duração (RTP) podem ter em estruturas com elevada razão de forma, fabricadas em substratos de silício. Com esse propósito, a sequência “clear – oxidize – remove – etch” (CORE) foi utilizada como principal processo de erosão, utilizando um equipamento dedicado a erosão reativa iónica em profundidade. Para a caracterização recorreu-se maioritariamente a microscopia eletrónica de varrimento, embora também se tenha recorrido a elipsometria. RTP refere-se a processos que impliquem aumentar a temperatura de um dado material, normalmente semicondutores, até valores elevados, num curto espaço de tempo (minutos ou mesmo segundos). Deste modo, pode ser utilizado como uma ferramenta multifuncional e bastante versátil, capaz de efetuar oxidação térmica, hidrogenação, recozimento, nitrogenação, entre outros. Neste projeto, focaram-se os primeiros três, conduzindo a vários estudos experimentais. De acordo com os resultados, o fenómeno de difusão atómica do silício, pela sua superfície, em estado sólido, foi presenciado, quer utilizando 5% hidrogénio/árgon ou apenas árgon como ambiente para recozimento térmico de curta duração (RTA). Assim, foi presenciada a transformação tridimensional (3D) das estruturas em silício ou a formação de espaços vazios no interior do Si (ESS). Contudo, foi reportada perda de volume de silício, possivelmente causado por sublimação e erosão por reação com oxigénio. Adicionalmente, foi possível obter filmes finos uniformes de óxido de silício – abaixo de 17 nm e 20 nm em superfícies Si (100) e Si (110), respetivamente. A remoção de black silicon (BSi) foi também conseguida através de RTA. De uma forma geral, aprofundar o conhecimento sobre estas técnicas permitirá a sua inserção, por exemplo, no processo de fabricação de dispositivos MOS e MEMS e no mundo de circuitos integrados à grande escala

Assessment of the bioactive and nutritional potential of novel food products enriched in Cystoseira abies-marina and Skeletonema sp. biomass

Mestrado em Engenharia Alimentar - Instituto Superior de AgronomiaMicro and macroalgae are photosynthetic organisms of large abundance and diversity that contain a variety of compounds with high bioactivity and nutritional value. These compounds have been receiving an increasing interest of researchers due to their potentially positive effect on human health. This has also led to the development of applications for algal biomass, ranging from animal feed to cosmetics, pharmaceuticals, and functional foods. The use of algae biomass in the food industry is still a new concept with the potential to produce healthy foods with added nutritional and bioactive compounds. Although there are many countless studies that support the health benefits of algae, few studies quantify the bioavailability of those nutritional compounds. In vitro digestion methods currently being used for studying the bioaccessibility of said nutrients and bioactive compounds, allowing a better understanding of how those compounds can be used. In this work two algae species, microalgae Skeletonema sp. and macroalgae Cystoseira abies-marina, that are not thoroughly studied were analysed regarding their proximal composition, lipid composition, element composition, phenolic content and relevant bioactivities, as well as their bioaccessibility, in order to understand their potential to be incorporated in food products. Two food products enriched in algae, sauce and cookies, were prepared and analysed, displaying a higher content in polyphenols and higher antioxidant activity than the control in the bioaccessible fraction. The high arsenic concentration found in the macroalgae is also observed in food products prepared with this species requiring a speciation study to assess the risk to human health. The mixture of the food ingredients with Skeletonema sp. was beneficial for the bioaccessibility of monounsaturated fats in sauces, which increased with the incorporation of the microalgae. This work reinforced that incorporating algae in food products can be advantageous, thereby paving the way for effective and marketable functional foodsN/

Study of Th17 cells in patients under peritoneal dialysis

Chronic Kidney Disease is a complex disease, with increasing prevalence in the world, and is defined by irreversible damage in the kidney structure and function. One of the most used treatments is peritoneal dialysis, that allows to preserve part of the renal function. However, in the long-term, it leads to peritoneal damage, that seems to be modulated by inflammatory processes and immune responses. Among these mediators, Th17 cells and IL-17A seem to play an important role in the pathogenesis of the disease. Therefore, this study aimed to quantify the populations of total lymphocytes, T cells, CD4+ and CD8+ T cells, Th17 and Th1 cells in peripheral blood and peritoneal effluent from 26 patients undergoing peritoneal dialysis and compare with peripheral blood from a control group, consisting of 10 healthy volunteers. The local IL-17A concentration in the serum and peritoneal effluent was also studied. The main differences were found in the frequencies of Th17 and Th1 cells, that were significantly lower in patients on peritoneal dialysis than in the control group. It was also observed that the frequency of Th1 cells was higher in the peritoneal effluent than in the blood. IL-17A concentration was significantly higher in the peritoneal effluent when compared to the serum. Although IL-17A levels do not follow the same pattern as some previous research, the results seem to suggest that in the patient's peritoneum, an inflammatory process is emerging, and further clarification is needed regarding the mechanisms of action of this cytokine in the pathology.A Doença Renal Crónica é uma doença complexa, cada vez mais prevalente no mundo, que se define por danos irreversíveis na estrutura e função do rim. Uma das terapias mais usadas é a diálise peritoneal, que permite preservar parte da função renal. No entanto, o seu uso a longo prazo leva à deterioração do peritoneu, sendo mediada por processos inflamatórios e respostas imunes. De entre estes fatores, as células Th17 e a IL-17A parecem assumir um papel de destaque na patogénese da doença. Deste modo, este trabalho teve como objetivo quantificar as populações de linfócitos totais, linfócitos T, linfócitos T CD4+ e CD8+, Th17 e Th1 no sangue periférico e no efluente peritoneal de 26 doentes a realizar diálise peritoneal e comparar com o sangue periférico de um grupo controlo, constituído por 10 indivíduos saudáveis. Também foi estudada a concentração local de IL-17A no soro e no efluente peritoneal. As principais diferenças foram observadas nas frequências de células Th17 e Th1, significativamente mais baixas nos doentes em diálise peritoneal do que no grupo controlo. Também foi observado que a frequência de células Th1 era mais elevada no efluente peritoneal do que no sangue. Relativamente à concentração de IL-17A, esta era significativamente mais elevada no efluente peritoneal, quando comparado com o soro. Apesar de os níveis de IL-17A não seguirem a tendência da maioria da literatura, os resultados parecem sugerir que um processo inflamatório se está a desenvolver no peritoneu destes doentes, que precisa de ser melhor caraterizado, de forma a clarificar qual a ação efetiva desta citocina na patologia

Bureaucracy vs. efficiency: how does bureaucracy impact the access to european funds - the impact of european funds on R&D investment by firms in Portugal

Due to the dynamic environment in which small and medium-sized businesses (SMEs) operate, they face unique problems. Through various tools and programs, public policies are attempting to boost the competitiveness and creativity of SMEs in this direction. This paper evaluates whether SMEs that received EU funds recorded an improvement in their intangible and tangible fixed assets investments and if those investments impact the perception of bureaucracy in the application process for EU funds. The findings demonstrate the efficiency of EU funds in encouraging investment in tangible assets while having some impact on the perception of bureaucracy

A cactus group action on a shifted tableau crystal and a shifted Berenstein-Kirillov group

Gillespie, Levinson and Purbhoo recently introduced a crystal-like structure for shifted tableaux, called the shifted tableau crystal. This structure may be regarded as a directed acyclic weighted graph, with coloured double edges, having vertices the shifted semistandard tableaux. It decomposes into connected components, each one having unique source vertex, whose weight is a strict partition, and sink vertex, with reverse weight. The character of each connected component is the Schur Q-function indexed by the said strict partition. Following a similar approach as Halacheva, for crystals of finite-dimensional representations of the quantized universal enveloping algebra of a finite-dimensional complex reductive Lie algebra, we exhibit a natural internal action of the n-fruit cactus group on the shifted tableau crystal, realized by the restrictions of the shifted Schützenberger involution to all primed intervals of the underlying crystal alphabet. This includes the shifted crystal reflection operators, which agree with the restrictions of the shifted Schützenberger involution to single-coloured connected components, but unlike the case for type A crystals, these do not need to satisfy the braid relations of the symmetric group. In addition, we define a shifted version of the Berenstein–Kirillov group, by considering shifted Bender–Knuth involutions. Paralleling the works of Halacheva and Chmutov, Glick and Pylyavskyy for type A semistandard tableaux of straight shape, we exhibit another occurrence of the cactus group action on shifted tableau crystals of straight shape via the action of the shifted Berenstein–Kirillov group. We also conclude that the shifted Berenstein–Kirillov group is isomorphic to a quotient of the cactus group. Not all known relations that hold in the classic Berenstein–Kirillov group need to be satisfied by the shifted Bender–Knuth involutions, but the ones implying the relations of the cactus group are verified, thus we have another presentation for the cactus group in terms of shifted Bender–Knuth involutions. We also use the shifted growth diagrams due to Thomas and Yong, together with the semistandardization process of Pechenik and Yong, to provide an alternative proof concerning the mentioned cactus group action

“Who do you say that I am?” Truth in Narrative Identity

The following article explores what notion of truth is possible in Ricœur’s narrative identity. It is motivated by the question of how our identity can be constituted in narratives of self when we are often easily self-deceiving and do not choose the building blocks of our narratives. It explores how our identities are constituted in narrative, with others, in order to see what dimensions of truth this allows. Narrative identity implicates a novel notion of truth that is intrinsically ethical, which gives rise to a set of ethical issues. In particular, a truth of self that occurs in relation to others is open to violence and abuse—our very identity is, to varying degrees, in others’ hands. Butler’s ethics of fragility may offer a positive solution.Le présent article tente de comprendre quel est le type de vérité auquel peut prétendre la notion ricœurienne d’identité narrative, en explorant la question suivante : comment notre identité peut-elle être constituée dans des récits de soi alors que nous nous trompons souvent facilement et que nous ne choisissons pas les éléments constitutifs de nos récits ? Il explore la manière dont nos identités sont constituées dans des récits, avec d’autres, afin de voir quelles dimensions de la vérité sont alors permises. L’identité narrative implique une nouvelle notion de vérité qui est intrinsèquement éthique, ce qui soulève une série de questions du même ordre. Dans la mesure en effet où une vérité de soi qui se produit en relation avec d’autres est exposée à la violence et aux abus — notre identité elle-même est, à des degrés divers, entre les mains d’autres individus. L’éthique de la fragilité de Butler est susceptible d’offrir une solution positive à cette question

A era do jornalismo digital : o caso do Jornal Expresso que ao semanário juntou uma edição diária

O jornalismo foi uma das áreas mais afectadas com o constante avanço das novas tecnologias durante a última década. A forma como se contam histórias e se dá a conhecer as notícias sofreu uma grande alteração e o seu paradigma está sempre em constante actualização. O presente relatório de estágio foi então construído com base na experiência de trabalho durante seis meses no jornal Expresso, onde a constante inovação dos meios veio trazer ao seio dos órgãos de comunicação social um jornal totalmente digital. A investigação teórico-prática orientada pelo Professor Doutor Rogério Santos analisa a estrutura e estratégia de um jornal tradicional que teve necessidade de se (re)adaptar para enfrentar o mercado que está em constante mudança e adaptação com o crescimento da tecnologia, criando um jornal digital único em Portugal. Desta forma, este relatório procura, através de entrevistas exploratórias e grelhas de análise, encontrar um padrão na publicação de artigos diários no jornal. Ou seja, a investigadora tenciona perceber qual o método de trabalho utilizado para a criação de um jornal digital, já que as ofertas ao nível da tecnologia são inúmeras permitindo aos jornais poupar tempo e recursos. As principais conclusões mostram que a internet incentiva o jornalista a ser um profissional sedentário e de rotinas. Ou seja, atrás do computador encontramos tudo aquilo que procuramos. Contundo, é este mesmo jornal digital que poderá atrair mais leitores. Com a inserção de conteúdos interactivos nas peças jornalísticas, o leitor vai sentir-se atraído pela novidade e pelas imagens que há muito deixaram de ser estáticas passando assim a ser apresentadas em vídeo e facilitando a sua leitura.Journalism was one of the most affected areas with the steady advance of new technologies over the last decade. The way how journalists tell stories and make news has changed and its paradigm is a constant updated. This internship report was built by the work experience for six months in the Expresso newspaper, where the constant innovation of media has brought into the social media a new digital newspaper. The theoretical and practical research supervised by Professor Rogerio Santos analyzes the structure and strategy of a traditional newspaper which had need to (re) adapt to face the market that is constantly changing and adapting to the technological growth, creating a unique digital newspaper in Portugal. Thus, this report search, through exploratory interviews and analysis grids, find a pattern in the publication of articles in the daily newspaper. I.e., the researcher try to realize what the working method is used to create a digital newspaper, once that the new media offers in terms of technology numerous resources which is able to save time and resources of the companies. The main conclusions show that the internet encourages the journalist to be a sedentary professional who lives by routines. This means that the journalist makes his job behind the computer where we find everything we need. However, this same online newspaper is the one which will attract more readers. With the interactive contents in news stories, the reader will be attracted by the novelty and by the images that are no more static, becoming presented on video, and thus facilitating the reading for the audience