Showing papers on "Fabrication published in 2007"
574 citations
TL;DR: In this article, a review of thin film deposition techniques and components relevant to micro solid oxide fuel cell (μSOFC) fabrication is presented, including current research on nanocrystalline thin film electrolyte and thin-film-based model electrodes.
328 citations
TL;DR: In this article, the authors review recent progress in interface engineering for the fabrication of high-performance OFETs and, in particular, engineering of the interfaces between semiconductors and insulators, and the effects of interfacial characteristics on the molecular and mesoscale structures of π-conjugated molecules and the performance of OFET devices.
290 citations
TL;DR: In this article, a method of fabricating complex metallic microstructures in 3D by injecting liquid solder into microfluidic channels, and allowing the solder to cool and solidify; after fabrication, the metallic structures can be flexed, bent, or twisted.
Abstract: This Communication describes a method of fabricating complex metallic microstructures in 3D by injecting liquid solder into microfluidic channels, and allowing the solder to cool and solidify; after fabrication, the metallic structures can be flexed, bent, or twisted This method of fabrication—which we call microsolidics—takes advantage of the techniques that were developed for fabricating microfluidic channels in poly(dimethylsiloxane) (PDMS) in 2D and 3D, uses surface chemistry to control the interfacial free energy of the metal– PDMS interface, and uses techniques based on microfluidics, but ultimately generates solid metal structures This approach makes it possible to build flexible electronic circuits or connections between circuits, complex embedded or freestanding 3D metal microstructures, 3D electronic components, and hybrid electronic–microfluidic devices There are several techniques for making metal microstructures in 3D Electroplating and electroless deposition are routinely used to construct microstructures with metallic layers several nanometers to several microns thick in 2D or 3D [1–11] To generate solid replicas of 3D objects, several groups have developed a technique, referred to as “microcasting”, to form metals in order to fabricate microparts (eg, posts and gears) with features as small as 10 lm and aspect ratios as high as 10 from steel, zirconia, and alumina [12,13] Techniques based on LIGA (Lithographie, Galvanoformung, und Abformung) produce even more complicated metallic objects by depositing a metal onto a molded polymer template that is subsequently removed to yield an open structure (such as a honeycomb arrangement of cells) [14,15] In principle, these approaches can be used to pattern metals of any thickness to produce features with an aspect ratio that is larger than that produced using electroplating
258 citations
TL;DR: Scaffolds used for bone engineering fabricated by solid free‐form fabrication combined with growth factors, HS and HS‐like molecules and other biologically active molecules are presented.
Abstract: A paradigm shift is taking place in orthopaedic and reconstructive surgery from using medical devices and tissue grafts to a tissue engineering approach that uses biodegradable scaffolds combined with cells or biological molecules to repair and/or regenerate tissues. One of the potential benefits offered by solid free-form fabrication technology (SFF) is the ability to create scaffolds with highly reproducible architecture and compositional variation across the entire scaffold, due to its tightly controlled computer-driven fabrication. In this review, we define scaffold properties and attempt to provide some broad criteria and constraints for scaffold design in bone engineering. We also discuss the application-specific modifications driven by surgeon's requirements in vitro and/or in vivo. Next, we review the current use of SFF techniques in scaffold fabrication in the context of their clinical use in bone regeneration. Lastly, we comment on future developments in our groups, such as the functionalization of novel composite scaffolds with combinations of growth factors; and more specifically the promising area of heparan sulphate polysaccharide immobilization within the bone tissue engineering arena.
250 citations
TL;DR: Different SU‐8‐based techniques have led to new low‐temperature processes suitable for the fabrication of a wide range of objects, from the single component to the complete lab‐on‐chip.
Abstract: Since its introduction in the nineties, the negative resist SU-8 has been increasingly used in micro- and nanotechnologies. SU-8 has made the fabrication of high-aspect ratio structures accessible to labs with no high-end facilities such as X-ray lithography systems or deep reactive ion etching systems. These low-cost techniques have been applied not only in the fabrication of metallic parts or molds, but also in numerous other micromachining processes. Its ease of use has made SU-8 to be used in many applications, even when high-aspect ratios are not required. Beyond these pattern transfer applications, SU-8 has been used directly as a structural material for microelectromechanical systems and microfluidics due to its properties such as its excellent chemical resistance or the low Young modulus. In contrast to conventional resists, which are used temporally, SU-8 has been used as a permanent building material to fabricate microcomponents such as cantilevers, membranes, and microchannels. SU-8-based techniques have led to new low-temperature processes suitable for the fabrication of a wide range of objects, from the single component to the complete lab-on-chip. First, this article aims to review the different techniques and provides guidelines to the use of SU-8 as a structural material. Second, practical examples from our respective labs are presented.
243 citations
TL;DR: In this article, a phototransistor based on an individual sub-micro/nanometer ribbon of copper hexadecafluorophthalocyanine (F16CuPc) was proposed.
Abstract: Photoelectronic devices of organic semiconductors are of great interest recently because organic semiconductors have many fundamental advantages over their inorganic counterparts. For example, their low cost is ideal for large-area applications and their mechanical flexibility makes them naturally compatible with plastic substrates for lightweight and foldable products. The most attractive prospect, however, is their incorporation of functionality by molecular design. Phototransistors have much higher sensitivity and lower noise than photodiodes and use these advantages to combine light detection and signal magnification properties that realize greater functionality in a single device. This is an important aspect of optoelectronic integration. Since the first concept of a phototransistor was proposed by William Shockley in 1951, inorganic phototransistors have been quickly developed and used in a variety of applications. However, few reports in the literature have addressed phototransistors made of organic semiconductors, especially organic single crystals. Organic single crystals have important merits in the study of intrinsic properties and for the fabrication of high-quality devices and circuits. Here, we used an organic semiconductor, copper hexadecafluorophthalocyanine (F16CuPc), as the candidate to introduce single-crystalline photoswitches and phototransistors of organic semiconductors. F16CuPc was selected not only because of its remarkable air-stable, n-type properties but also because of its high thermal and chemical stability. Bao et al. first paid attention to this compound in 1998. Recently, Dosch and Barrena and co-workers carefully investigated its structure and self-organization properties on a solid surface. In addition, we synthesized single-crystalline sub-micro/nanoribbons of the compound by a physical vapor transport technique and studied its field-effect performance; we demonstrated its high field-effect mobility and on/ off ratio in transistors based on an individual ribbon. However, the optical properties of this air-stable, n-type material, are still unclear. In this Communication, we study these properties by using devices made of single-crystalline sub-micro/ nanometer ribbons of F16CuPc. Single-crystalline sub-micro/nanometer ribbons of F16CuPc were synthesized and transferred or in-situ patterned onto Si/ SiO2 (300 nm) substrates, as previously described. [6,7] Devices based on an individual sub-micro/nanometer ribbon were fabricated by the “multiple-times gold-wire mask moving” technique based on the asymmetrical drain/source electrode (Au/Ag) configuration shown in Figure 1—because such a configuration was beneficial for injection, transport, and collection. The ribbon thickness in the devices was measured carefully by atomic force microscopy. C O M M U N IC A TI O N
212 citations
TL;DR: In this article, a low viscosity mono-or oligomeric precursor is used to impregnate the fibers, followed by in situ polymerization, and then the fibers are used for manufacturing thermoplastic composite parts.
Abstract: Thermoplastic composites offer some interesting advantages over their thermoset counterparts like a higher toughness, faster manufacturing and their recyclable nature. Traditional melt processing, however, limits thermoplastic composite parts in size and thickness. As an alternative, reactive processing of textile fiber-reinforced thermoplastics is discussed in this paper: a low viscosity mono- or oligomeric precursor is used to impregnate the fibers, followed by in situ polymerization. Processes that are currently associated to manufacturing of thermoset composites like resin transfer molding, vacuum infusion and resin film infusion, might be used for manufacturing of thermoplastic composite parts in near future. This paper gives an overview of engineering and high-performance plastic materials that are suitable for reactive processing and discusses fundamental differences between reactive processing of thermoplastic and thermoset resins.
204 citations
TL;DR: In this paper, the development of a novel free-form fabrication technique using a cold spray (CS) system was reported, where metallic powder particles are accelerated in a supersonic gas jet and impacted with a substrate at speeds in excess of 600 m/s.
Abstract: This paper reports on the development of a novel freeform fabrication technique using a cold spray (CS) system. In the CS process, metallic powder particles are accelerated in a supersonic gas jet and impacted with a substrate at speeds in excess of 600 m/s. The non-melting nature of its deposition mechanism ensures that the sprayed material is free from thermally induced tensile stresses, while the underlying substrate remains unchanged. The process is seen as a viable method for additive manufacturing because of its high deposition rates and controllable spray jet. A process was developed to investigate the potential of non-thermal freeform fabrication and was coined Cold Gas Dynamic Manufacturing (CGDM). Here, additive and subtractive techniques were combined to enable the production of complex geometries. Whereas most CS facilities concentrate on the application of wear or corrosion-resistant coatings, CGDM is dedicated to the production of freeform components, whilst still retaining an inherent coating ability. The process can produce functional forms using novel manufacturing strategies that are unique to CS. This paper presents information on the process, and details the various strategies employed during component fabrication. It was possible to construct components from many materials, including titanium, which exhibited freeform surfaces, internal channels and embedded devices. A breakdown of the process economics is also provided, with and without helium recycling.
195 citations
TL;DR: It is shown in this letter that using this device, N-methylaniline can be detected using its well-defined absorption fingerprint of the N-H bond near 1496 nm, and given the low-cost fabrication process used, and robust device configuration, the integration scheme provides a promising device platform for chemical sensing applications.
Abstract: We have fabricated and tested, to the best of our knowledge, the first microfluidic device monolithically integrated with planar chalcogenide glass waveguides on a silicon substrate. High-quality Ge(23)Sb(7)S(70) glass films have been deposited onto oxide coated silicon wafers using thermal evaporation, and high-index-contrast channel waveguides have been defined using SF(6) plasma etching. Microfluidic channel patterning in photocurable resin (SU8) and channel sealing by a polydimethylsiloxane (PDMS) cover completed the device fabrication. The chalcogenide waveguides yield a transmission loss of 2.3 dB/cm at 1550 nm. We show in this letter that using this device, N-methylaniline can be detected using its well-defined absorption fingerprint of the N-H bond near 1496 nm. Our measurements indicate linear response of the sensor to varying N-methylaniline concentrations. From our experiments, a sensitivity of this sensor down to a N-methylaniline concentration 0.7 vol. % is expected. Given the low-cost fabrication process used, and robust device configuration, our integration scheme provides a promising device platform for chemical sensing applications.
188 citations
TL;DR: In this paper, a high resolution organic field effect transistor (OFET) fabrication process was developed based on the selective laser sintering of ink-jet printed nanoparticle inks and the recent development of an air stable carboxylate-functionalized polythiophene semiconducting polymer.
Abstract: A high resolution organic field effect transistor (OFET) fabrication process has been developed based on the selective laser sintering of ink-jet printed nanoparticle inks and the recent development of an air stable carboxylate-functionalized polythiophene semiconducting polymer. The entire fabrication and device characterization are performed at room temperature, ambient pressure, and air environment without using complex lithographic methods. This low temperature OFET fabrication process based on nanoparticle laser sintering has great potential for realizing inexpensive, large area flexible electronics on heat sensitive polymer substrates.
TL;DR: A drop-on-demand (DOD) ink-jetting system was used to print gold nano-particles suspended in Alpha-Terpineol solvent, PVP (poly-4-vinylphenol) in PGMEA (propylene glycol monomethyl ether acetate) solvent, semiconductor polymer (modified polythiophene) in chloroform solution to fabricate passive and active electrical components on flexible polymer substrates as discussed by the authors.
Abstract: The low temperature fabrication of passive (conductor, capacitor) and active (field effect transistor) electrical components on flexible polymer substrate is presented in this paper. A drop-on-demand (DOD) ink-jetting system was used to print gold nano-particles suspended in Alpha-Terpineol solvent, PVP (poly-4-vinylphenol) in PGMEA (propylene glycol monomethyl ether acetate) solvent, semiconductor polymer (modified polythiophene) in chloroform solution to fabricate passive and active electrical components on flexible polymer substrates. Short pulsed laser ablation enabled finer electrical components to overcome the resolution limitation of inkjet deposition. Continuous argon ion laser was irradiated locally to evaporate the carrier solvent as well as sinter gold nano-particles. In addition, selective ablation of multilayered gold nanoparticle film was demonstrated using the novel SPLA-DAT (selective pulsed laser ablation by different ablation threshold) scheme for sintered and non-sintered gold nanoparticles. Finally, selective ablation of multilayered film was used to define narrow FET (field effect transistor) channel. Semiconductor polymer solution was deposited on top of channel to complete OFET (organic field effect transistor) fabrication.
TL;DR: In this paper, a hot-cutting technique is used to separate the parts from the bulk metallic glass reservoir, which enables a clean planar separation of the part from the BMG reservoir and also allows to net shape three-dimensional parts on the micron scale.
Abstract: A technology for microelectromechanical systems (MEMS) and microstructure fabrication is introduced where the bulk metallic glass (BMG) is formed at a temperature where the BMG exist as a viscous liquid under an applied pressure into a mold. This thermoplastic forming is carried out under comparable forming pressure and temperatures that are used for plastics. The range of possible sizes in all three dimensions of this technology allows the replication of high strength features ranging from about 30 nm to centimeters with aspect ratios of 20 to 1, which are homogeneous and isotropic and free of stresses and porosity. Our processing method includes a hot-cutting technique that enables a clean planar separation of the parts from the BMG reservoir. It also allows to net-shape three-dimensional parts on the micron scale. The technology can be implemented into conventional MEMS fabrication processes. The properties of BMG as well as the thermoplastic formability enable new applications and performance improvements of existing MEMS devices and nanostructures
TL;DR: In this paper, the authors examined the suitability of the Ultrasonic Consolidation (UC) process for fabrication of parts in multi-materials and found that most of the materials investigated can be successfully bonded to alloy Al 3003 and vice versa.
Abstract: Purpose – Ultrasonic consolidation (UC) is a novel additive manufacturing process developed for fabrication of metallic parts from foils. While the process has been well demonstrated for part fabrication in Al alloy 3003, some of the potential strengths of the process have not been fully explored. One of them is its suitability for fabrication of parts in multi‐materials. This work aims to examine this aspect.Design/methodology/approach – Multi‐material UC experiments were conducted using Al alloy 3003 foils as the bulk part material together with a number of engineering materials (foils of Al‐Cu alloy 2024, Ni‐base alloy Inconel 600® AISI 347 stainless steel, and others). Deposit microstructures were studied to evaluate bonding between various materials.Findings – It was found that most of the materials investigated can be successfully bonded to alloy Al 3003 and vice versa. SiC fibers and stainless wire meshes were successfully embedded in an Al 3003 matrix. The results suggest that the UC process is qu...
TL;DR: In this paper, a laser forward transfer technique using the decomposition of a thin triazene polymer film by a XeCl excimer laser was used for fabrication of a polymer light-emitting device.
Abstract: Fabrication of a polymer light-emitting device was achieved by a laser forward transfer technique using the decomposition of a thin triazene polymer film by a XeCl excimer laser The dry deposition process allows transfer of a bilayer consisting of the electroluminescent polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] covered with an aluminum electrode onto a receiver substrate The soft transfer results in laterally well resolved pixels (≈500μm), whose fluorescence as well as electroluminescence spectra remain unaltered The rectifying and smooth current-voltage characteristics add to the merits of this laser-based transfer method that opens up the possibility of direct-writing heat- and UV-sensitive materials
TL;DR: A facile method to control the volume phase transition kinetics of thermo-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels is presented in this article.
Abstract: A facile method to control the volume-phase transition kinetics of thermo-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels is presented Monodisperse PNIPAM microgels with spherical voids are prepared using a microfluidic device The swelling and shrinking responses of these microgels with spherical voids to changes in temperature are compared with those of voidless microgels of the same size and chemical composition prepared using the same microfluidic device It is shown that the PNIPAM microgels with voids respond faster to changes in temperature as compared with their voidless counterparts Also, the induced void structure does not have a detrimental effect on the equilibrium volume change of the microgels Thus, the volume phase transition kinetics of the microgels can be finely tuned by controlling the number and size of the voids The flexibility, control, and simplicity in fabrication rendered by this approach make these microgels appealing for applications that range from drug delivery systems and chemical separations to chemical/biosensing and actuators
TL;DR: A conical polymer microneedle design is presented that is fabricated using a novel integrated lens technique and analyzed for its ability to insert into the skin without mechanical failure and demonstrated to insert to different depths into porcine skin in vitro.
Abstract: Administration of protein and DNA biotherapeutics is limited by the need for hypodermic injection. Use of micron-scale needles to deliver drugs in a minimally invasive manner provides an attractive alternative, but application of this approach is limited by the need for suitable microneedle designs and fabrication methods. To address this need, this paper presents a conical polymer microneedle design that is fabricated using a novel integrated lens technique and analyzed for its ability to insert into the skin without mechanical failure. Microneedle master structures were fabricated using microlenses etched into a glass substrate that focused light through SU-8 negative epoxy resist to produce sharply tapered structures. Microneedle replicates were fabricated out of biodegradable polymers by micromolding. Because microneedle mechanical properties are critical to their insertion into the skin, we theoretically modeled two failure modes (axial mode and transverse mode), and analytical models were compared with measured data showing general agreement. Guided by this analysis, polymer microneedles were designed and demonstrated to insert to different depths into porcine skin in vitro. "Long" polymer microneedles were also demonstrated in human subjects to insert deeply without failure
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17 Sep 2007
TL;DR: In this article, the authors present an introduction to microelectronic fabrication and discuss the properties of selected Semiconductor materials, including properties of the Error Function F values index and the conversion factor.
Abstract: 1. An Introduction to Microelectronic Fabrication 2. Semiconductor Substrates 3. Diffusion 4. Thermal Oxidation 5. Ion Implantation 6. Rapid Thermal Processing 7. Optical Lithography 8. Photoresists 9. Nonoptical Lithographic Techniques 10. Vacuum Science and Plasmas 11 . Etching 12. Physical Deposition: Evaporation and Sputtering 13. Chemical Vapor Deposition 14. Epitaxial Growth 15. Device Isolation, Contacts, and Metallization 16. CMOS Technologies 17. Other Transistor Technologies 18. Optoelectronic Technologies 19. MEMS. 20. Integrated Circuit Manufacturing Acronyms and Common Symbols Properties of Selected Semiconductor Materials Physical Constants Conversion Factors Some properties of the Error Function F Values Index
TL;DR: These glassy films having very good mechanical and chemical properties, combined with superb nano-patterning ability, integrateable with silicon integrated circuit technology, are promising for fabrication of a wide range of two- or three-dimensional components for future nano-electromechanical systems.
Abstract: Completely glassy thin films of Zr-Al-Cu-Ni exhibiting a large supercooled liquid region (DeltaT(x) = 95 K), very smooth surface (R(a) = 0.2 nm) and high value of Vickers hardness (H(v) = 940) were deposited by sputtering. The micro/nano-patterning ability of these films is demonstrated by focused ion beam etching (smallest pattern approximately 12 nm), as well as by the imprint lithography technique (smallest feature approximately 34 nm). These glassy films having very good mechanical and chemical properties, combined with superb nano-patterning ability, integrateable with silicon integrated circuit technology, are promising for fabrication of a wide range of two- or three-dimensional components for future nano-electromechanical systems.
TL;DR: A detailed optical study of the iridescent outer shell of the beetle Plusiotis boucardi has revealed a novel microstructure which controls both the polarization and wavelength of reflected light as mentioned in this paper.
Abstract: A detailed optical study of the iridescent outer-shell of the beetle Plusiotis boucardi has revealed a novel microstructure which controls both the polarizationandwavelengthofreflectedlight.Apreviouslyunreportedhexagonal array across the integument of the beetle exhibits highly localized regions of reflection of only red and green left-handed circularly-polarized light. Optical and transmission electron microscopy (TEM) imaging reveals the origin of this effect as an array of 'bowl-shaped' recesses on the elytra that are formed from a dual-pitch helicoidal layer. Reflectivity spectra collected from the beetle are compared to theoretical data produced using a multi-layer optics model for modelling chiral, optically anisotropic media such as cholesteric liquid crystals. Excellent agreement is obtained between data and theory produced using a model that incorporates an upper isotropic layer (of cuticular wax), followed by a short pitch (310 (±1)nm)overlying a longer pitch (370 (±1)nm)helicoidal layer of optically anisotropic material. These layers are backed by an absorbing underlayer. Synthetic replication of this form of structure may provide a route to the fabrication of tuneable micro-mirrors for optical applications.
TL;DR: In this article, an intelligent methodology to determine the optimal fabrication direction is proposed to minimize the required post-machining region (RPMR) in the LM, an expression of the distribution of surface roughness is presented and the relation between the RPMR and fabrication direction are investigated taking real LM environments into consideration.
Abstract: Layered manufacturing (LM) can fabricate any complex 3D physical model without geometric limitations by depositing 2D layers in a given direction. However, the surface of the LM processed part is excessively rough in comparison with that of general NC machined part due to the LM process itself. Hence to improve the surface quality, additional post-machining such as coating and grinding process is required. This post-machining, however, is also detrimental to the original geometry of the part and is time consuming. To minimize the required post-machining region (RPMR) in the LM, an intelligent methodology to determine the optimal fabrication direction is proposed in this paper. An expression of the distribution of surface roughness is presented and the relation between the RPMR and fabrication direction is investigated taking real LM environments into consideration. The objective is to minimize the RPMR for general LM technology. A genetic algorithm is applied to obtain reliable solution for a complex geometry CAD model. Validity and effectiveness of the proposed methodology are tested by various experiments and applications.
TL;DR: This work demonstrates the simple and low-cost fabrication without nanolithography of monolithic and planar nanochannels by hot-embossing and bonding below the glass transition temperature.
Abstract: Planar nanochannels are of particular significance in nanofluidics: keeping the width on the micrometre scale prevents the use of nanolithography while the depth stays in the nanometric range, i.e. below 100 nm. Fabrication of wide and shallow nanochannels in a plastic is known to be challenging due to the collapse of the structure during the sealing step. In this Technical Note, we demonstrate the simple and low-cost fabrication without nanolithography of monolithic and planar nanochannels by hot-embossing and bonding below the glass transition temperature.
TL;DR: In this paper, a method for the fabrication of gradient-refractive index lenses that is based on a method of polymer forced assembly is presented. But the method is limited to a single lens and cannot handle a wide range of lens shapes and index profiles.
Abstract: The recognition that eye lenses in nature often employ a gradient refractive index to enhance the focusing power and to correct aberrations has motivated us to construct a synthetic lens using the layered concept encountered in biological lenses. The result is a highly flexible technology for the fabrication of gradient-refractive index lenses that is based on a method of polymer forced assembly. Polymeric nanolayered films with incremental differences in the refractive index are assembled according to a prescribed design and molded into the desired shape. The exceptional flexibility of the process lies in the wide range of lens shapes and index profiles that can be realized. A lens with any refractive index distribution can be achieved within the refractive index range of available coextrudable optical materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1834–1841, 2007
TL;DR: In this paper, the authors present the results of their studies on conceptual design and feasibility experiments towards development of a novel hybrid manufacturing process to fabricate fuel cell bipolar plates that consists of multi-array micro-channels on a large surface area.
TL;DR: In this article, a thermal evaporation-deposition approach using microwave energy was employed for the fabrication of ZnO micro-and nano-structures, including microtubes, microrods, nanowires and nanobelts.
TL;DR: It is demonstrated that arrays of nanowires of conjugated polymers can be easily produced by a simple embossing protocol, compatible with very large scale integration technology and significantly enhancing their performance.
Abstract: We demonstrate that arrays of nanowires of conjugated polymers can be easily produced by a simple embossing protocol, compatible with very large scale integration technology. The embossing process is shown to have the supplementary virtue to increase the internal degree of order of the nanowires, significantly enhancing their performance. This is applied to the fabrication of nanowire-based devices consisting of a liquid crystalline light-emitting polymer, of a liquid crystalline semiconducting polymer, and of an amorphous conducting polymer, illustrating the versatility and wide applicability of the method.
17 Jun 2007
TL;DR: In this paper, the design and fabrication of high-Q air-core toroidal inductors are described, and a fabrication process using a combination of thin-film processes and conventional machining has been used to make prototypes.
Abstract: The design and fabrication of high-Q air-core toroidal inductors are described. Designs are optimized for maximum Q for a given size and inductance, independent any particular fabrication process. A fabrication process using a combination of thin-film processes and conventional machining has been used to make prototypes. Measurements performed on the first prototypes confirm the predicted Q of 115 at 50 MHz.
TL;DR: In this article, the fabrication of long thin holes with a high aspect ratio of 100 (diameter: 10 μm, depth: 1 mm) in biodegradable polymer material (polylactic acid, referred to herein as PLA) using a UV excimer laser was reported.
Abstract: The present paper reports the fabrication of long thin holes with a high aspect ratio of 100 (diameter: 10 μm, depth: 1 mm) in biodegradable polymer material (polylactic acid, referred to herein as PLA) using a UV excimer laser. Holes having diameters of 10, 20 and 50 μm are fabricated from the side surface of a PLA sheet, and their fabricated shapes are observed using an optical microscope. These holes are compared with holes fabricated in other polymer sheets. It is proven that a long thin hole can be fabricated in PLA material, although at a lower fabrication rate compared that for epoxy material. This laser fabrication is applied to a PLA microneedle, which is fabricated by the micromolding technique. A hole is fabricated along the centerline of the newly developed microneedle, and it is confirmed experimentally that blood plasma is taken into this hole by capillary force.
TL;DR: In this paper, a planar Peltier microcooler was fabricated on a 12 µm thick Kapton(c) polyimide substrate using Bi2Te3 and Sb2Te 3 thermoelectric elements deposited by thermal co-evaporation.
Abstract: The present work reports on the fabrication and characterization of a planar Peltier cooler on a flexible substrate. The device was fabricated on a 12 µm thick Kapton(c) polyimide substrate using Bi2Te3 and Sb2Te3 thermoelectric elements deposited by thermal co-evaporation. The cold area of the device is cooled with four thermoelectric junctions, connected in series using metal contacts. Plastic substrates add uncommon mechanical properties to the composite film–substrate and enable integration with novel types of flexible electronic devices. Films were deposited by co-evaporation of tellurium and bismuth or antimony to obtain Bi2Te3 or Sb2Te3, respectively. Patterning of the thermoelectric materials using lift-off and wet-etching techniques was studied and compared. The performance of the Peltier microcooler was analysed by infrared image microscopy, on still-air and under vacuum conditions, and a maximum temperature difference of 5 °C was measured between the cold and the hot sides of the device.