Mems device with large out-of-plane actuation and low-resistance interconnect and methods of use

Source: United States Patent and Trademark Office, www.uspto.gov”The present application is directed to a MEMS device. The MEMS device includes a substrate having a first end and a second end extending along a longitudinal axis, the Substrate including an electrostatic actuator. The device also includes a movable plate having a first end and a second end. The device also includes a thermal actuator having a first end coupled to the first end of the substrate and a second end coupled to the first end of the plate. The actuator moves the plate in relation to the substrate. Further, the device includes a power source electrically coupled to the thermal actuator and the Substrate. The application is also directed to a method for operating a MEMS device

Digital transformation in the automotive supply chain: China, Germany, Italy and Japan in a comparative perspective

A wide literature on digital transformation in manufacturing and services has explored its impact on long term changes in labour demand and skills and on productivity and growth. A new perspective on the ongoing digital transformation has been prompted by Oecd to highlight specific metrics needed to assess its impact on the economy and society and to support innovat on policies. Drawing on these contributions, this paper aims to shed light on the impact of digital transformation on the reorganization and relocation of the various segments of the automotive supply chain. In particular, it will focus on the effects generated by different paces of adoption of digital technologies in this supply chain, with regard to both the various segments and the various sizes of companies, in different countries. The causes of this heterogeneity will be discussed and the implications for the full impact of the ongoing transformation will be considered in relation to industrial and innovation policy in Europe. The paper addresses the issue by reviewing empirical evidence on the automotive supply chain, which includes the most advanced manufacturing and service companies that are now adopting digital technologies. Evidence from case studies in the automotive industry in China, Germany, Italy and Japan will help in identifying the main challenges of digital transformation for European countries, which will involve a strongly interrelated supply chain both within and outside Europe

Fabrication and characterization of hybrid energy harvesting microdevices

In this dissertation, a hybrid energy harvesting system based on a lead zirconate titanate (PZT) and carbon nanotube film (CNF) cantilever structure has been designed, fabricated and studied. It has the ability to harvest light and thermal radiation energy from ambient energy and convert them to electricity. The proposed micro-scale energy harvesting device consists of a composite cantilever beam (SU-8/CNF/Pt/PZT/Pt) which is fixed on a silicon based anchor and two electrode pads for wire bonding. The CNF acts as an antenna to receive radiation energy and convert it to heat energy and then transfer to the whole cantilever structure. The CNF will also convert the radiation energy to a non-uniform distributed static charge. These are two major reasons that cause the cantilever to bend and give the ability of cyclic bending back and forth of the cantilever. The PZT layer, in turn, converts the mechanical energy of repeated deformation of the cantilever to electricity by the piezoelectric effect. First, the cyclic bending capability of the composite cantilever when receiving radiation energy, named self-reciprocation, has been evaluated by copper-CNF cantilever structures and the proposed mechanisms have been discussed. Based on this idea, a prototype macro-scale device with PZT and CNF integrated has been used to verify the possibility of harvesting energy from light and thermal sources by the self-reciprocation phenomenon. Open circuit voltage (OCV) output recorded from the prototype device showed continuous oscillation while a constant radiation source was presented. The proposed micro-scale energy harvesting device was then designed and the fabrication process flow has been developed using surface and bulk micromachining techniques. The fabricated device was polarized in a strong electric field at raised temperature to boost the piezoelectric coefficient. A validation step is designed to pick out the working devices before testing. The functioned device was then tested and successfully demonstrated to harvest energy from light and thermal sources. The result showed the power density of the micro-scale device is 4,445 times higher than the macro-scale prototype device calculated from the maximum power transfer theorem. It was found that the electric output of the micro-scale device contains not only the AC component as the prototype device but also a DC bias shift added to the AC component. An equivalent structure model of the micro-scale device was established to study the electric output characteristic. It was realized that the DC bias shift is generated from the thermoelectric effect (Seebeck effect) by controlled experiments and analysis. The performance of the micro device was studied under different levels of light and thermal radiation conditions. The relationship between output (both DC and AC components of open circuit voltage and short circuit current) and input (light and thermal energy) were analyzed by the least square regression method. The device was taken out of the laboratory to demonstrate its ability to harvest energy in ambient conditions. Both the DC and AC components of the open circuit voltage (electricity) were able to be generated from the solar and wind energy. The power density generated from a single device was about 4 µW/cm2. Further enhancement of the power density was proved by concentrating solar energy on the device with a magnifier and operating an arrayed device

MEMS tunable infrared metamaterial and mechanical sensors

Sub-wavelength resonant structures open the path for fine controlling the near-field at the nanoscale dimension. They constitute into macroscopic “metamaterials” with macroscale properties such as transmission, reflection, and absorption being tailored to exhibit a particular electromagnetic response. The properties of the resonators are often fixed at the time of fabrication wherein the tunability is demanding to overcome fabrication tolerances and afford fast signal processing. Hybridizing dynamic components such as optically active medium into the device makes tunable devices. Microelectromechanical systems (MEMS) compatible integrated circuit fabrication process is a promising platform that can be merged with photonics or novel 2D materials. The prospect of enormous freedom in integrating nanophotonics, MEMS actuators and sensors, and microelectronics into a single platform has driven the rapid development of MEMS-based sensing devices. This thesis describes the design and development of four tunable plasmonic structures based on active media or MEMS, two graphene-based MEMS sensors and a novel tape-based cost-effective nanotransfer printing techniques. First of all, we present two tunable plasmonic devices with the use of two active medium, which are electrically controlled liquid crystals and temperature-responsive hydrogels, respectively. By incorporating a nematic liquid crystal layer into quasi-3D mushroom plasmonic nanostructures and thanks to the unique coupling between surface plasmon polariton and Rayleigh anomaly, we have achieved the electrical tuning of the properties of plasmonic crystal at a low operating electric field. We also present another tunable plasmonic device with the capability to sense environmental temperature variations. The device is bowtie nanoantenna arrays coated with a submicron-thick, thermos-responsive hydrogel. The favorable scaling of plasmonic dimers at the nanometer scale and ionic diffusion at the submicron scale is leveraged to achieve strong optical resonance and rapid hydrogel response, respectively. Secondly, we present two MEMS -based tunable near-to-mid infrared metamaterials on a silicon-on-insulator wafer via electrically and thermally actuating the freestanding nanocantilevers. The two devices are developed on the basis of the same fabrication process and are easy-to-implement. The electrostatically driven metamaterial affords ultrahigh mechanical modulation (several tens of MHz) of an optical signal while the thermo-mechanically tunable metamaterial provides up to 90% optical signal modulation at a wavelength of 3.6 õm. Next, we present MEMS graphene-based pressure and gas flow sensors realized by transferring a large area and few-layered graphene onto a suspended silicon nitride thin membrane perforated with micro-through-holes. Due to the increased strain in the through-holes, the pressure sensor exhibits a very high sensitivty outperformed than most existing MEMS-based pressure sensors using graphene, silicon, and carbon nanotubes. An air flow sensor is also demonstrated via patterning graphene sheets with flow-through microholes. The flow rate of the air is measured by converting the mechanically deflection of the membrane into the electrical readout due to the graphene piezeroresistors. Finally, we present a tape-based multifunctional nanotransfer printing process based on a simple stick-and-peel procedure. It affords fast production of large-area metallic and dielectric nanophotonic sensing devices and metamaterials using Scotch tape

Theoretical Analysis of Torsionally Vibrating Microcantilevers for Chemical Sensor Applications in Viscous Liquids

Dynamically driven microcantilevers excited in the transverse (or out-of-plane) direction are widely used as highly sensitive chemical sensing platforms in various applications. While these devices work very well in air, their performance in liquids is not efficient because of the combination of increased viscous damping and effective fluid mass. In order to improve the characteristics of microcantilevers in liquid environments, some other vibration modes such as the torsional mode and lateral (or in-plane) flexural mode have been proposed.In this work, the characteristics of torsionally vibrating rectangular microcantilevers with length L, width b and thickness h in viscous liquids are investigated taking into account the thickness effects. Finite element models are used to obtain the hydrodynamic loading (torque per unit length) and thus calculate values of the hydrodynamic function. An analytical expression of the hydrodynamic function in terms of the Reynolds number and aspect ratio, h/b, is then obtained by fitting the numerical results. This allows for the characteristics to be investigated as a function of both beam geometry and fluid properties, considering thickness effects on the torsional constant, the hydrodynamic function and the polar moment of area. For high aspect ratios, (h/b\u3e0.16) microcantilevers vibrating in the 1st torsional mode, ignoring thickness effects could result in a minimum error of 9%, 5%, 20%, 7% for the resonance frequency, quality factor, mass sensitivity, and normalized mass limit of detection, respectively. Clearly, for many sensing applications based on analyzing the resonance frequency and mass sensitivity, thickness effects should be taken into account. The resonance frequency is found to be dependent on h/(bL) and the quality factor is found to be dependent on h/L1/2 for microcantilevers vibrating in the 1st torsional mode in viscous liquids. In comparison, for microcantilevers vibrating in the 1st lateral mode, the resonance frequency is dependent on b/L2 and the quality factor is dependent on hb1/2/L. Such different trends can be used to optimize device geometry and liquid property, thus maximizing quality factor and sensitivity in chemical sensing applications. Compared with microcantilevers in the 1st transverse mode, microcantilevers that vibrate in their first torsional mode have higher resonance frequency and quality factor. The increase in resonance frequency and quality factor results in higher sensitivity and reduced frequency noise, respectively. This will yield much lower limits of detection in liquid-phase chemical sensing applications

3D complex shaped- dissolvable multi level micro/nano mould fabrication

There is growing interest in the development of fabrication techniques to cost effectively mass-produce high-resolution (micro/nano) 3D structures in a range of materials. Biomedical applications are particularly significant. This work demonstrates a novel technique to simultaneously fabricate a sacrificial mould having the inverse shape of the desired device structure and also create the desired device structure using electroplating deposition techniques. The mould is constructed of many thin layers using a photoresist material that is dissolvable and sensitive to UV light. At the same time the device is created in the emerging mould layers using Gold electroplating deposition technique. Choosing to fabricate the mould and the 3D structures in multiple thin layers allows the use of UV light and permits the potential cost-effective realization of 3D curved surfaces, the accuracy and geometric details of which are related to the number of layers used. In this work I present a novel idea to improve the LIGA process when using many masks to deposit multi thin layer over each other. Moreover, this technique can be utilized to produce a curved surface in the vertical direction with any diameter. Practically, a 2 µm thickness of layer is applied in the proposed technique. However, a layer of 0.5 µm or less can be deposited. An example is provided to explain the novel fabrication process and to outline the resulting design and fabrication constraints. With this technique, any structure could be made and any material used. The work employs conventional techniques to produce a 3D complex shape. By using conventional techniques with multi layers to produce a 3D structure, many problems are expected to occur during the process. Those problems were mentioned by many researchers in general but have not been addressed correctly. Most researchers have covered those problems by leaving the conventional and using a new technique they invented to produce the required product. However, in my work I have addressed those problems for the first time and I offered a new and effective technique to improve the MEMS technology and make this technology cheaper. This was achieved by using a research methodology requiring a rigorous review of existing processes, as outlined above, then by proposing a concept design for an improved process. This novel proposed process was then tested and validated by a series of experiments involving the manufacture of demo-devices. The conclusion is that this new process has the potential to be developed into a commercially implementable process

Acousto optic modulated stroboscopic interferometer for comprehensive characterization of microstructure

Mechanical and electro-mechanical advancements to the nano-scale require comprehensive and systematic testing at the micro-scale in order to understand the underlying influences that define the micro/nano-device both from fabrication and operational points of view. In this regard, surface metrology measurements, as well as static and dynamic characteristics will become very important and need to be experimentally determined to describe the system fully. These integrated tests are difficult to be implemented at dimensions where interaction with the device can seriously impact the results obtained. Hence, a characterization method to obtain valid experimental information without interfering with the functionality of the device needs to be developed. In this work, a simple yet viable Acousto Optic Modulated Stroboscopic Interferometer (AOMSI) was developed using a frequency stabilized Continuous Wave (CW) laser together with an Acousto Optic Modulator for comprehensive mechanical characterization to obtain surface, static and dynamic properties of micro-scale structures. An optimized methodology for measurement was established and sensitivity analysis was conducted. Being a whole-field technique, unlike single point or scanning interferometers, AOMSI can provide details of surface properties as well as displacements due to static/dynamic loads and modal profiles. Experiments for surface profiling were carried out on a micro-mirror, along with 2D and 3D profile measurements. The ability of AOMSI to perform dynamic measurements was tested on Micro-Cantilevers and on AFM (Atomic Force Microscopy) cantilevers. The resolution of AOMSI was identified as 10nms. The results for static deflections, 1 st and 2 nd natural frequencies and mode shapes were found to be in good agreement with results from the developed theoretical model and manufacturers specifications. The approach is a novel approach to investigate the surface, static and dynamic behavior of microstructures using a single interferometer

MEMS Actuation and Self-Assembly Applied to RF and Optical Devices

The focus of this work involves optical and RF (radio frequency) applications of novel microactuation and self-assembly techniques in MEMS (Microelectromechanical systems). The scaling of physical forces into the micro domain is favorably used to design several types of actuators that can provide large forces and large static displacements at low operation voltages. A self-assembly method based on thermally induced localized plastic deformation of microstructures has been developed to obtain truly three-dimensional structures from a planar fabrication process. RF applications include variable discrete components such as capacitors and inductors as well as tunable coupling circuits. Optical applications include scanning micromirrors with large scan angles (>90 degrees), low operation voltages (<10 Volts), and multiple degrees of freedom. One and two-dimensional periodic structures with variable periods and orientations (with respect to an incident wave) are investigated as well, and analyzed using optical phased array concepts. Throughout the research, permanent tuning via plastic deformation and power-off latching techniques are used in order to demonstrate that the optical and RF devices can exhibit zero quiescent power consumption once their geometry is set

Учебно-методическое пособие по переводу английских научно-технических текстов

Пособие формирует и развивает навыки и умение перевода английских научно-технических текстов. Оно предназначено для студентов II и III курсов, изучающие компьютерные системы. А также интеллектуальные приборы и интегральные сенсорные системы. Пособие включает как теоретический материал по технике перевода, лексическим и лексико-семантическим особенностями научно-технической литературы, так и практический курс, состоящий из оригинальных текстов и упражнений к ним, направленных на изучение и укрепление лексических и грамматических особенностей

Fabrication of high-aspect-ratio metallic micro-structures by reverse exposure method

Master'sMASTER OF ENGINEERIN