Reliability Of Mems Testing Of Materials And Devices PdfBy Marcial C. In and pdf 24.03.2021 at 05:46 9 min read
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- IEC 62047 Series - Micro-Electromechanical Devices - MEMS
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- Nanoelectromechanical systems
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IEC 62047 Series - Micro-Electromechanical Devices - MEMS
Nanoelectromechanical systems NEMS are a class of devices integrating electrical and mechanical functionality on the nanoscale. NEMS typically integrate transistor-like nanoelectronics with mechanical actuators, pumps, or motors, and may thereby form physical, biological, and chemical sensors. The name derives from typical device dimensions in the nanometer range, leading to low mass, high mechanical resonance frequencies, potentially large quantum mechanical effects such as zero point motion , and a high surface-to-volume ratio useful for surface-based sensing mechanisms.
As noted by Richard Feynman in his famous talk in , " There's Plenty of Room at the Bottom ," there are many potential applications of machines at smaller and smaller sizes; by building and controlling devices at smaller scales, all technology benefits. The expected benefits include greater efficiencies and reduced size, decreased power consumption and lower costs of production in electromechanical systems. In , Mohamed M. Further devices have been described by Stefan de Haan. A key application of NEMS is atomic force microscope tips.
The increased sensitivity achieved by NEMS leads to smaller and more efficient sensors to detect stresses, vibrations, forces at the atomic level, and chemical signals. Two complementary approaches to fabrication of NEMS can be found. The top-down approach uses the traditional microfabrication methods, i.
While being limited by the resolution of these methods, it allows a large degree of control over the resulting structures. In this manner devices such as nanowires , nanorods, and patterned nanostructures are fabricated from metallic thin films or etched semiconductor layers. For top-down approaches, increasing surface area to volume ratio enhances the reactivity of nanomaterials. Bottom-up approaches, in contrast, use the chemical properties of single molecules to cause single-molecule components to self-organize or self-assemble into some useful conformation, or rely on positional assembly.
This allows fabrication of much smaller structures, albeit often at the cost of limited control of the fabrication process. Furthermore, while there are residue materials removed from the original structure for the top-down approach, minimal material is removed or wasted for the bottom-up approach. A combination of these approaches may also be used, in which nanoscale molecules are integrated into a top-down framework. One such example is the carbon nanotube nanomotor.
Many of the commonly used materials for NEMS technology have been carbon based, specifically diamond ,   carbon nanotubes and graphene. This is mainly because of the useful properties of carbon based materials which directly meet the needs of NEMS.
The mechanical properties of carbon such as large Young's modulus are fundamental to the stability of NEMS while the metallic and semiconductor conductivities of carbon based materials allow them to function as transistors. Both graphene and diamond exhibit high Young's modulus, low density, low friction, exceedingly low mechanical dissipation,  and large surface area.
Along with the mechanical benefits of carbon based materials, the electrical properties of carbon nanotubes and graphene allow it to be used in many electrical components of NEMS. Nanotransistors have been developed for both carbon nanotubes  as well as graphene. Nanomechanical resonators are frequently made of graphene. As NEMS resonators are scaled down in size, there is a general trend for a decrease in quality factor in inverse proportion to surface area to volume ratio.
Furthermore, it has been theoretically predicted that clamping graphene membranes on all sides yields increased quality numbers. Graphene NEMS can also function as mass,  force,  and position  sensors.
Carbon nanotubes CNTs are allotropes of carbon with a cylindrical nanostructure. They can be considered a rolled up graphene. When rolled at specific and discrete " chiral " angles, and the combination of the rolling angle and radius decides whether the nanotube has a bandgap semiconducting or no bandgap metallic. Metallic carbon nanotubes have also been proposed for nanoelectronic interconnects since they can carry high current densities.
Carbon nanotubes have specifically found so much use in NEMS that methods have already been discovered to connect suspended carbon nanotubes to other nanostructures. Because carbon based products can be properly controlled and act as interconnects as well as transistors, they serve as a fundamental material in the electrical components of NEMS.
Limitations on switching speed and actuation voltage can be overcome by scaling down devices from micro to nanometer scale. Despite all of the useful properties of carbon nanotubes and graphene for NEMS technology, both of these products face several hindrances to their implementation. Carbon nanotubes exhibit a large change in electronic properties when exposed to oxygen. Carbon nanotubes were also found to have varying conductivities, being either metallic or semiconducting depending on their helicity when processed.
Graphene also has complicated electric conductivity properties compared to traditional semiconductors because it lacks an energy band gap and essentially changes all the rules for how electrons move through a graphene based device. By suspending a silicon proof mass on a double-layer graphene ribbon, a nanoscale spring-mass and piezoresistive transducer can be made with the capability of currently produced transducers in accelerometers.
The spring mass provides greater accuracy, and the piezoresistive properties of graphene converts the strain from acceleration to electrical signals for the accelerometer. The suspended graphene ribbon simultaneously forms the spring and piezoresistive transducer, making efficient use of space in while improving performance of NEMS accelerometers.
Failures arising from high adhesion and friction are of concern for many NEMS. NEMS frequently utilize silicon due to well-characterized micromachining techniques; however, its intrinsic stiffness often hinders the capability of devices with moving parts. A study conducted by Ohio State researchers compared the adhesion and friction parameters of a single crystal silicon with native oxide layer against PDMS coating.
PDMS is a silicone elastomer that is highly mechanically tunable, chemically inert, thermally stable, permeable to gases, transparent, non-fluorescent, biocompatible, and nontoxic. PDMS can form a tight seal with silicon and thus be easily integrated into NEMS technology, optimizing both mechanical and electrical properties.
Polymers like PDMS are beginning to gain attention in NEMS due to their comparatively inexpensive, simplified, and time-efficient prototyping and manufacturing. Rest time has been characterized to directly correlate with adhesive force,  and increased relative humidity lead to an increase of adhesive forces for hydrophilic polymers.
PDMS coatings facilitate mitigation of high-velocity problems, such as preventing sliding. Thus, friction at contact surfaces remains low even at considerably high velocities.
In fact, on the microscale, friction reduces with increasing velocity. The hydrophobicity and low friction coefficient of PDMS have given rise to its potential in being further incorporated within NEMS experiments that are conducted at varying relative humidities and high relative sliding velocities. For instance, PDMS coating on a diaphragm can be used for chloroform vapor detection. Researchers from the National University of Singapore invented a polydimethylsiloxane PDMS -coated nanoelectromechanical system diaphragm embedded with silicon nanowires SiNWs to detect chloroform vapor at room temperature.
In the presence of chloroform vapor, the PDMS film on the micro-diaphragm absorbs vapor molecules and consequently enlarges, leading to deformation of the micro-diaphragm. The SiNWs implanted within the micro-diaphragm are linked in a Wheatstone bridge, which translates the deformation into a quantitative output voltage.
In addition, the micro-diaphragm sensor also demonstrates low-cost processing at low power consumption. By switching the vapor-absorption polymer layer, similar methods can be applied that should theoretically be able to detect other organic vapors.
In addition to its inherent properties discussed in the Materials section, PDMS can be used to absorb chloroform, whose effects are commonly associated with swelling and deformation of the micro-diaphragm; various organic vapors were also gauged in this study.
With good aging stability and appropriate packaging, the degradation rate of PDMS in response to heat, light, and radiation can be slowed.
The emerging field of bio-hybrid systems combines biological and synthetic structural elements for biomedical or robotic applications. The constituting elements of bio-nanoelectromechanical systems BioNEMS are of nanoscale size, for example DNA, proteins or nanostructured mechanical parts.
Examples include the facile top-down nanostructuring of thiol-ene polymers to create cross-linked and mechanically robust nanostructures that are subsequently functionalized with proteins. Computer simulations have long been important counterparts to experimental studies of NEMS devices. Through continuum mechanics and molecular dynamics MD , important behaviors of NEMS devices can be predicted via computational modeling before engaging in experiments. Failure of NEMS devices can be attributed to a variety of sources, such as mechanical, electrical, chemical, and thermal factors.
Identifying failure mechanisms, improving yield, scarcity of information, and reproducibility issues have been identified as major challenges to achieving higher levels of reliability for NEMS devices.
Such challenges arise during both manufacturing stages i. Factors of wafer dicing, device thickness, sequence of final release, thermal expansion, mechanical stress isolation, power and heat dissipation, creep minimization, media isolation, and protective coatings are considered by packaging design to align with the design of the MEMS or NEMS component.
Wafer-level encapsulation techniques can lead to improved reliability and increased yield for both micro and nanodevices. Assessing the reliability of NEMS in early stages of the manufacturing process is essential for yield improvement. Forms of surface forces, such as adhesion and electrostatic forces, are largely dependent on surface topography and contact geometry. Selective manufacturing of nano-textured surfaces reduces contact area, improving both adhesion and friction performance for NEMS.
Adhesion and friction can also be manipulated by nanopatterning to adjust surface roughness for the appropriate applications of the NEMS device. Roughness on hydrophilic surfaces versus hydrophobic surfaces are found to have inversely correlated and directly correlated relationships respectively.
Due to its large surface area to volume ratio and sensitivity, adhesion and friction can impede performance and reliability of NEMS devices. These tribological issues arise from natural down-scaling of these tools; however, the system can be optimized through the manipulation of the structural material, surface films, and lubricant.
In comparison to undoped Si or polysilicon films, SiC films possess the lowest frictional output, resulting in increased scratch resistance and enhanced functionality at high temperatures. Hard diamond-like carbon DLC coatings exhibit low friction, high hardness and wear resistance, in addition to chemical and electrical resistances.
Roughness, a factor that reduces wetting and increases hydrophobicity, can be optimized by increasing the contact angle to reduce wetting and allow for low adhesion and interaction of the device to its environment. Material properties are size-dependent. Therefore, analyzing the unique characteristics on NEMS and nano-scale material becomes increasingly important to retaining reliability and long-term stability of NEMS devices.
These measurements, however, do not consider how the device will operate in industry under prolonged or cyclic stresses and strains. The theta structure is a NEMS model that exhibits unique mechanical properties. Composed of Si, the structure has high strength and is able to concentrate stresses at the nanoscale to measure certain mechanical properties of materials.
To increase reliability of structural integrity, characterization of both material structure and intrinsic stresses at appropriate length scales becomes increasingly pertinent. Residual stresses can influence electrical and optical properties. For instance, in various photovoltaic and light emitting diodes LED applications, the band gap energy of semiconductors can be tuned accordingly by the effects of residual stress.
Atomic force microscopy AFM and Raman spectroscopy can be used to characterize the distribution of residual stresses on thin films in terms of force volume imaging, topography, and force curves.
Key hurdles currently preventing the commercial application of many NEMS devices include low-yields and high device quality variability. Before NEMS devices can actually be implemented, reasonable integrations of carbon based products must be created. A recent step in that direction has been demonstrated for diamond, achieving a processing level comparable to that of silicon. Carbon-based materials have served as prime materials for NEMS use, because of their exceptional mechanical and electrical properties.
Incorporation of electronic displacement transducers based on piezoresistive thin metal film facilitates unambiguous and efficient nanodevice readout. From Wikipedia, the free encyclopedia.
Further information: Nanotechnology and History of nanotechnology. Main article: Biological machine.
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Reliability and Failure of Electronic Materials and Devices is a well-established and well-regarded reference work offering unique, single-source coverage of most major topics related to the performance and failure of materials used in electronic devices and electronics packaging. With a focus on statistically predicting failure and product yields, this book can help the design engineer, manufacturing engineer, and quality control engineer all better understand the common mechanisms that lead to electronics materials failures, including dielectric breakdown, hot-electron effects, and radiation damage. This new edition adds cutting-edge knowledge gained both in research labs and on the manufacturing floor, with new sections on plastics and other new packaging materials, new testing procedures, and new coverage of MEMS devices. Professional Materials Engineers working with materials used in electronic devices, including silicon chips; Electronics Engineers; Electrical Engineers; Manufacturing Engineers; Chemical Engineers. From this perspective and the well-written tutorial style of the book, the reader will gain a deeper physical understanding of failure mechanisms in electronic materials and devices; acquire skills in the mathematical handling of reliability data; and better appreciate future technology trends and the reliability issues they raise. He retired from IBM in after 30 years.
Reliability of MEMS: Testing of Materials and Devices. August Request Full-text Paper PDF. To read the full-text of this research.
It seems that you're in Germany. We have a dedicated site for Germany. Authors: Hartzell , Allyson L. Successfully bringing MEMS-based products to market hinges on engineering the component to have sufficient reliability for the intended application, yet the reliability and qualification methodology for MEMS based products is not widely understood.
Many highly integrated and easy to deploy condition monitoring products are appearing on the market that employ a micro electromechanical system MEMS accelerometer as the core sensor.
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Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. Cost reduction is the most prominent challenge facing the assembly and packaging of MEMS. Packaging currently represents more than 80 percent of the cost of some systems and is often the leading cause of system failure. MEMS packaging is usually approached by individual manufacturers on a specialized, application-specific basis in which problems are solved independently. Very little publicly available work has been conducted on the basic aspects of generic packaging and assembly or on standardized packaging methodologies for MEMS. The imbalance between the ease with which batch-fabricated MEMS can be produced and the difficulty and cost of packaging and testing them limits the speed with which new MEMS can be introduced into the market.
New methods are needed in microsystems technology for evaluating microelectromechanical systems MEMS because of their reduced size. The assessment and characterization of mechanical and structural relations of MEMS are essential to assure the long-term functioning of devices, and have a significant impact on design and fabrication. Within this study a concept for the investigation of mechanically loaded MEMS materials on an atomic level is introduced, combining high-resolution X-ray diffraction HRXRD measurements with finite element analysis FEA and mechanical testing. Latter were calculated by a specifically developed, simple and fast approach on the basis of continuum mechanical relations. Qualitative and quantitative analysis confirmed the admissibility and accuracy of the presented method. Consequently, the introduced procedure contributes to further going investigations of weak scattering being related to strain and defects in crystalline structures and therefore supports investigations on materials and devices failure mechanisms.
Reliability of Mems: Testing of Materials and Devices is available in our digital library an online access to it is set as public so you can get it.
Nanoelectromechanical systems NEMS are a class of devices integrating electrical and mechanical functionality on the nanoscale. NEMS typically integrate transistor-like nanoelectronics with mechanical actuators, pumps, or motors, and may thereby form physical, biological, and chemical sensors. The name derives from typical device dimensions in the nanometer range, leading to low mass, high mechanical resonance frequencies, potentially large quantum mechanical effects such as zero point motion , and a high surface-to-volume ratio useful for surface-based sensing mechanisms. As noted by Richard Feynman in his famous talk in , " There's Plenty of Room at the Bottom ," there are many potential applications of machines at smaller and smaller sizes; by building and controlling devices at smaller scales, all technology benefits. The expected benefits include greater efficiencies and reduced size, decreased power consumption and lower costs of production in electromechanical systems. In , Mohamed M. Further devices have been described by Stefan de Haan.
This 22 standard series starts from the basics with terms, definitions, and general specs, and continues on to a range of measurements and test methods such as those for fatigue, compression, bending, and shearing. IEC defines terms for micro-electromechanical devices including the process of production of such devices. This edition includes the following significant technical changes with respect to the previous edition: a removal of ten terms; b revision of twelve terms; c addition of sixteen new terms. Specifies the method for tensile testing of thin film materials with length and width under 1 mm and thickness under 10 m, which are main structural materials for micro-electromechanical systems MEMS , micromachines and similar devices. The main structural materials for MEMS, micromachines and similar devices have special features such as typical dimensions in the order of a few microns, a material fabrication by deposition, and a test piece fabrication by non-mechanical machining using etching and photolithography. This International Standard specifies the testing method, which enables a guarantee of accuracy corresponding to the special features. Specifies a standard test piece, which is used to guarantee the propriety and accuracy of a tensile testing system for thin film materials with length and width under 1 mm and thickness under 10 m, which are main structural materials for microelectromechanical systems MEMS , micromachines and similar devices.