Titel "Korte inhoud" "Design, Fabrication and Characterization of Tunnel Field Effect Transistors for Ultra-Low Power CMOS Applications (Ontwerp, fabricatie en karakterisatie van tunnel veld effect transistoren voor ultra-laag vermogen CMOS toepassingen)" "Silicon CMOS has emerged over the last 25 years as the predominant technology of the microelectronics industry. The concept of device scaling has been consistently applied over many technology generations, resulting in consistent improvement in both device density and performance. In the last decade, the shrinking of the transistor dimensions led to short channel effects (SCEs) which decreases the device performance. As a consequence, additional improvements were needed to maintain the performance improvements such as the introduction of SiGe S/D stressors to increase the carrier mobility due to the strain in the channel, the implementation of high-K and metal gate to reduce the gate leakage and, finally, the introduction of a new 3D architecture, finFET, to further suppress the SCEs. On the other hand, no solutions exist for the scaling of the dissipated power of the transistor. In fact, the scaling of the supply voltage (Vdd) is limited by the kT/q limit of the subthreshold slope which represents a physical limit for conventional MOSFETs. As a consequence, a new operation principle is needed.In this context, the Tunnel FET (TFET) has been proposed as a potential candidate to replace the MOSFET because its carrier injection mechanism based on quantum mechanical tunneling of the electrons from valence band to the conduction band and it is not subjected to the kT/q limit. The basic embodiment of TFET is a gated p-i-n diode. This thesis addresses the design, fabrication and characterization of TFETs following a CMOS compatible processing flow. The main goal is to understand the features of band to band tunneling from an experimental point of view and identify the best processing conditions and the best architecture for TFETs. The analysis starts from silicon homojunction gated p-i-n diodes to heterojunction devices where the source is replaced with SiGe with different germanium concentrations. Two different architectures are studied: finFETs and vertical nanowires. The finFETs are used as a test vehicle to study Si TFETs since the finFET processing is already mature. On the other hand, the vertical architecture is used to implement hetero junction TFET. Finally, in view of the limitations for the basic TFET embodiments, a new architecture to boost the on current of TFETs is proposed and analyzed by TCAD simulations." "Unitless Fabrication - Measurement in Digital Fabrication" "Danny Leen" "The process of creating objects is continually changing, from handcrafting to mass production and, more recently, digital fabrication. Today, computer numerical controlled (CNC) machines relieve us of the time-consuming and tedious task of learning to use manual equipment. Furthermore, the exponential growth of digital fabrication labs (FabLabs, Makerspaces, and Hackerspaces) ensures that all individuals have access to technology such as laser cutters, CNC milling machines, and 3D printers. As a result, a new movement of makers was formed that create one-of-a-kind objects. However, creating objects remains challenging for makers due to the industry's emphasis on precise and interchangeable components. Moreover, measurement tools and workflows are developed for the purpose of producing things that conform to rigorous tolerances. Regrettably, many of these tools and workflows are too involved for (novice) makers. As a result, makers typically use measurement instruments found in the lab or at home to capture, evaluate, and reconstruct certain physical characteristics. This dissertation investigates the role of measurement in the context of makers using digital fabrication machines. We show that novel measurement techniques and tools streamline the process of creating (functional) objects. Thus, lowering the threshold for non-expert makers to design, fabricate, and assemble objects when using digital fabrication tools. This research describes three main contributions that facilitate measurements in the digital fabrication process. Each contribution introduces novel tools and techniques that assist makers with measurements. First, we present how to bridge the gap between the digital and real worlds using tangible modeling techniques. Second, we show how hand-held power tools can be used with the same precision as digital fabrication machines. Third, we present a method for avoiding measurements during assembly by creating functional objects that can be folded into a three-dimensional shape. We demonstrate how each contribution works by developing the system and validating its operation by creating proof-of-concept objects and presenting various use cases. We conclude this work by discussing the general implications of novel measurement techniques in digital fabrication." "A semi-skilled fabrication approach of shape-changing interfaces through fused filament fabrication" "Robin Vandormael, Kamie Leten, Marieke Van Camp, Jouke Casper Verlinden, Regan Watts" "The common additive manufacturing techniques like fused filament fabrication (FFF) routinely produce physical, rigid structures. But using this production technique for manufacturing flexible structures with high-end materials such as thermoplastic polyurethane (TPU) is more difficult. Because of its difficulty, the fabrication of these structures requires higher-end machinery, time-intensive fabrication, and skilled users. Therefore, we focus on the malleable dynamics of a rigid thermoplastics with mid-range FFF technology to expand the design-space of shape-changing interfaces and propose a fabrication approach for it. As a result, the intended user, for example a creative designer, can also integrate shape-changing interfaces of rigid thermoplastics in their designs, much sooner than if constrained by an FFF printing platform. In a first phase, we experiment with different materials through an iterative design-based process. In a second phase, we perform an explorative design-case study to test the material’s flexibility and the fabrication approach. The research is concluded with an approach proposal, discussion and future work." "Gradient-temperature hot-embossing for dense micropillar array fabrication on thick cyclo-olefin polymeric plates: An example of a microfluidic chromatography column fabrication" "Ioannis Kourmpetis, Athina S. Kastania, Kosmas Ellinas, Katerina Tsougeni, Martyna Maria Baca, Wim De Malsche, Evangelos Gogolides" "The fabrication of dense and high aspect ratio pillar arrays is important for several applications. In particular polymeric microfluidic chromatography columns are of high importance for various biological, pharmaceutical and chemical separations. Here, a cyclo-olefin polymeric (COP) microcolumn fabrication process is developed using hot embossing with a temperature gradient for replication of a fine and highly dense array of micropillars on the surface of a 2mm thick polymer plate without chip deformation. The design consists of an array of ordered cylindrical pillars with 15 mu m diameter, 4 mu m interpillar, and 2 mu m pillar-wall distance with 20 mu m height. The produced microcolumn is subsequently sealed with thermal bonding in a laminator and tested for liquid pressure operation up to 20 bar. Since COPs are hydrophobic by nature and have been used for reversed-phase liquid chromatographic (RPLC) separations in the past, preliminary separation experiments are also demonstrated in the fabricated column." "Fabrication of photonic integrated circuits using high resolution CMOS fabrication process" "shankar kumar Selvaraja" "Fabrication of photonic integrated circuits using high resolution CMOS fabrication process" "shankar kumar Selvaraja" "Melt exit flow modelling and experimental validation for fused filament fabrication : from Newtonian to non-Newtonian effects" "Tom Van Waeleghem, Flavio Marchesini de Oliveira, Ludwig Cardon" "Challenges in the fabrication of biodegradable and implantable optical fibers for biomedical applications" "Agnieszka Gierej, Thomas Geernaert, Sandra Van Vlierberghe, Peter Dubruel, Hugo Thienpont, Francis Berghmans" "The limited penetration depth of visible light in biological tissues has encouraged researchers to develop novel implantable light-guiding devices. Optical fibers and waveguides that are made from biocompatible and biodegradable materials offer a straightforward but effective approach to overcome this issue. In the last decade, various optically transparent biomaterials, as well as different fabrication techniques, have been investigated for this purpose, and in view of obtaining fully fledged optical fibers. This article reviews the state-of-the-art in the development of biocompatible and biodegradable optical fibers. Whilst several reviews that focus on the chemical properties of the biomaterials from which these optical waveguides can be made have been published, a systematic review about the actual optical fibers made from these materials and the different fabrication processes is not available yet. This prompted us to investigate the essential properties of these biomaterials, in view of fabricating optical fibers, and in particular to look into the issues related to fabrication techniques, and also to discuss the challenges in the use and operation of these optical fibers. We close our review with a summary and an outline of the applications that may benefit from these novel optical waveguides." "Design, simulation and testing of a cloud platform for sharing digital fabrication resources for education" "Javier Mateos, Abdellah Touhafi, Gabriel-Miro Muntean" "Cloud and IoT technologies have the potential to support applications that are not strictly limited to technical fields. This paper shows how digital fabrication laboratories (Fab Labs) can leverage cloud technologies to enable resource sharing and provide remote access to distributed expensive fabrication resources over the internet. We call this new concept Fabrication as a Service (FaaS), since each resource is exposed to the internet as a web ser- vice through REST APIs. The cloud platform presented in this paper is part of the NEWTON Horizon 2020 technology-enhanced learning project. The NEWTON Fab Labs architecture is described in detail, from system concep- tion and simulation to system cloud deployment and testing in NEWTON project small and large-scale pilots for teaching and learning STEM subjects." "UNDULATUS: design and fabrication of a self-interlocking modular shell structure based on curved-line folding" "Stijn Brancart, Aline Vergauwen, Kelvin Roovers, Dimitri Van Den Bremt, Lars De Laet, Niels De Temmerman" "Curved-line folding is the act of folding a flat sheet of material along a curved crease pattern in order to create a three-dimensional shape. It is a creative and innovative way to produce lightweight and geometrically stiff components using only sheet materials. The pavilion presented in this paper integrates this principle in a kit-of-parts system. After being cut out of flat plates, the components get their 3D shape by folding them along a set of predefined curved lines. This deformed geometry, variable in its degree of bending, results in a structurally efficient ‘building block’ that can be combined into different structural configurations depending on its mode of assembly. The components form a weave pattern by connecting them ‘flap to leg’ respectively. As such, adjacent components lock each other into their rigid three-dimensional configuration and a modular shell structure is obtained. When composed of identical components, the obtained structure combines the advantages of rapid fabrication and assembly with an extensive reuse of components. However, the pavilion demonstrates that more geometrically and aesthetically challenging compositions, consisting of a series of custom-made components, are also possible and manageable when using digital fabrication techniques. Furthermore, this paper presents and discusses the digital modelling methods used for the design of the pavilion, as well as the lessons learned by real scale fabrication and assembly."