Category Archives: MEMS

By Heidi Hoffman, senior director of technology community marketing, SEMI

This year’s MEMS & Sensors Technical Congress(MSTC), February 19-20, 2019, features a deep dive into the changing automotive sensor landscape, a look at emerging MEMS technologies, and an exploration of integration standards. The more technically focused of SEMI’s annual MEMS events, MSTC returns to Monterey, California, in conjunction with FLEX, the conference that highlights new form factors enabled by advances in flexible, printed and hybrid electronics.

What’s next for automotive sensors

Leading technologists from across the automotive sensor value chain will share their views on emerging opportunities and challenges in that rapidly evolving market. Ford Motor Co. Executive Technical Director, Palo Alto Research Center, Dragos Maciuca will give an update on the changing demands of the market in his keynote. Another keynoter, ON SemiconductorCTO Hans Stork will focus on recent developments in sensors and integration technology, and the remaining challenges to integrate these complex data streams into cost-effective intelligent sensor fusion.

PNI Sensor President & CEO Becky Oh will report on advancements in smart parking sensor solutions and their deployment in smart cities. VerizonProduct Manager Nancy Ranxing Li will introduce Verizon’s data-driven approach to reduce injury and death in traffic accidents. Featuring an integrated sensor system that detects and analyzes conflicts among pedestrians, vehicles and cyclists, the Verizon system identifies potentially dangerous situations at intersections. Cities can use the data to make changes to improve safety while 5G-enabled self-driving cars can use the data to prevent accidents. Fabu Head of Marketing Angela Suen will discuss Fabu’s experience in applying machine learning to sensor integration data. Analog Devices, GM, Inertial Sensors, Tony Zarola will address nuances of autonomous transportation, including maintaining navigation assistance when vehicle sensors “go blind” as well as vehicle health-monitoring.

Emerging MEMS technologies

Other sessions feature major MEMS makers and researchers sharing innovations on a wide range of technology challenges: from reducing power consumption and increasing intelligence in sensors to MEMS motors, analog in-memory computing, and human/electronics interfaces.

UC Berkeley Professor Kristofer Pister will introduce the next generation of low-power wireless sensor networks, which now featuring self-contained power, MEMS sensors, microwatt computation and communication hardware. Now being demonstrated at UC Berkeley, the ultra-high-reliability devices offer the 10ms latency suitable for factory automation. Pister will also discuss ultra-efficient MEMS motors for wirelessly controlled haptics as well as micro robots for precision manipulation.

Syntiant Corp. VP of Product Mallik Moturi will report on the company’s neural decision processors, which use analog in-memory computing for ultra-low-power parallel processing. The company says that the devices are being designed into multiple kinds of edge devices, particularly for always-on speaker identification and key-word spotting for under 40µW—reportedly 50-100X more efficient than a GPU.

STMicroelectronic sSenior Manager, MEMS, Jay Esfandyari will discuss how the integration of logic into MEMS inertial measurement units (IMUs) enables independently programmable gesture recognition algorithms on the IMU – enabling a range of motion-detection gestures at a fraction of the power of running the algorithms on an external microcontroller. InvenSense CTO Peter Hartwell will share his company’s vision of the future in which sensors bridge the real and virtual worlds. Arm Senior Product Manager Tim Menasveta will explore Arm’s work in extending machine learning to resource-constrained embedded devices.

Georgia Tech Research Fellow Yun-Soung Kim will present a new wireless skin-like electronics platform for persistent human-machine interfaces. The platform — SKINTRONICS — combines thin-film processes, soft material engineering and miniature chip components to adapt electronics that conform to the soft, curvilinear and dynamic human body. Georgia Tech researchers have demonstrated using SKINTRONICS-enabled wireless human-machine interfaces to send electrical signals from the human body to control remotely a car and a wheelchair.

In the area of improving manufacturing technology and standards, Siemens/Mentor GM Greg Lebsackwill discuss the challenges and opportunities of co-design of MEMS and ICs for a more robust system and faster time to market. Lebsack will look at the design flow and the ecosystem of mixed-signal design tools and IP blocks for innovative system solutions for the IoT. NIST Project Leader Michael Gaitan will discuss improved test protocols for tri-axis MEMS accelerometers that better determine cross-axis sensitivities and are less sensitive to misalignment of devices on the test equipment, promoting more accurate testing in laboratory comparisons. Intel Platform Manager Ken Foust will discuss the impact and future of the MIPI I3C standard — a two-wire interface developed to address many key pain-points universally felt by system developers struggling to integrate broad sensor capability into their platforms.

MSTC is organized by MEMS & Sensors Industry Group, SEMI technology community.

 

Researchers from the University of Houston have reported significant advances in stretchable electronics, moving the field closer to commercialization.

Researchers from the University of Houston have reported significant advances in the field of stretchable, rubbery electronics. Credit: University of Houston

In a paper published Friday, Feb. 1, in Science Advances, they outlined advances in creating stretchable rubbery semiconductors, including rubbery integrated electronics, logic circuits and arrayed sensory skins fully based on rubber materials.

Cunjiang Yu, Bill D. Cook Assistant Professor of mechanical engineering at the University of Houston and corresponding author on the paper, said the work could lead to important advances in smart devices such as robotic skins, implantable bioelectronics and human-machine interfaces.

Yu previously reported a breakthrough in semiconductors with instilled mechanical stretchability, much like a rubber band, in 2017.

This work, he said, takes the concept further with improved carrier mobility and integrated electronics.

“We report fully rubbery integrated electronics from a rubbery semiconductor with a high effective mobility … obtained by introducing metallic carbon nanotubes into a rubbery semiconductor with organic semiconductor nanofibrils percolated,” the researchers wrote. “This enhancement in carrier mobility is enabled by providing fast paths and, therefore, a shortened carrier transport distance.”

Carrier mobility, or the speed at which electrons can move through a material, is critical for an electronic device to work successfully, because it governs the ability of the semiconductor transistors to amplify the current.

Previous stretchable semiconductors have been hampered by low carrier mobility, along with complex fabrication requirements. For this work, the researchers discovered that adding minute amounts of metallic carbon nanotubes to the rubbery semiconductor of P3HT – polydimethylsiloxane composite – leads to improved carrier mobility by providing what Yu described as “a highway” to speed up the carrier transport across the semiconductor.

CEA-Leti today announced it has prototyped a next-generation optical chemical sensor using mid-infrared silicon photonics that can be integrated in smartphones and other portable devices.

Mid-IR chemical sensors operate in the spectral range of 2.5µm to 12µm, and are considered the paradigm of innovative silicon-photonic devices. In less than a decade, chemical sensing has become a key application for these devices because of the growing potential of spectroscopy, materials processing, and chemical and biomolecular sensing, as well as security and industrial applications. Measurement in this spectral range provides highly selective, sensitive and unequivocal identification of chemicals.

The coin-size, on-chip, IoT-ready sensors prototyped by Leti combine high performance and low power consumption and enable such consumer uses as air-quality monitoring in homes and vehicles, and wearable health and well-being applications. Industrial uses include real-time air-quality monitoring and a range of worker-safety applications.

Mid-IR optical sensors available on the market today are typically bulky, shoebox-size or bigger, and cost more than €10,000. Meanwhile, current miniaturized and inexpensive sensors cannot meet consumer requirements for accuracy, selectivity and sensitivity. While size and price are not the most critical concerns for industrial applications, bulky and costly optical sensors represent a major barrier for consumer applications, which require wearability and integration in a range of portable devices.

CEA-Leti presented its R&D results Feb. 05 at SPIE Photonics West 2019 in a paper titled “Miniaturization of Mid-IR Sensors on Si: Challenges and Perspectives”.

“Mid-IR silicon photonics has enabled creation of a novel class of integrated components, allowing the integration at chip level of the main building blocks required for chemical sensing,” said Sergio Nicoletti, lead author of the paper. “Key steps in this development extend the wavelength range available from a single source, handling and routing of the beams using photonic-integrated circuits, and the investigation of novel detection schemes that allow fully integrated on-chip sensing.”

CEA-Leti’s breakthrough combined three existing technologies necessary to produce on-chip optical chemical sensors:

  • Integrating a mid-IR laser on silicon
  • Developing photonic integrated circuits (PICs) in the mid-IR wavelength range, and
  • Miniaturizing a photoacoustic detector on silicon chips.

“While other R&D efforts have had similar results, our project’s key achievement is the use of tools and processes typical of the IC and MEMS industries,” Nicoletti said. “Our focus on the choice of the architectures and processes, and the specific linkage of the series of steps also were critical to developing this optical chemical sensor, which CEA-Leti is now realizing as demo prototypes.”

Laser systems specialist LPKF Laser & Electronics, based in Hannover, Germany has added a foundry service for thin glass substrates to its product portfolio. The company recently introduced the Laser-Induced Deep Etching technology, or LIDE for short, a process for the precise and highly efficient manufacturing of through-glass vias (TGV) and other deep micro features in thin glass substrates. The LIDE process is able to overcome past limitations in glass drilling and micro machining as it combines very high productivity and low manufacturing cost with the superior quality of a direct data process, forgoing masks or photo processing.

With the introduction of its new independent foundry service, LPKF is hoping to make the LIDE technology available on a much wider scale, covering both prototyping and experimental applications as well as scalable mass production capacity. The service is aimed at the manufacturing of glass substrates for advanced IC and MEMS packaging as well as micro-machining of spacer wafers,microfluidics and other specialty glass applications. LPKF’s new foundry service is located at its corporate headquarters and will operate under the company’s Vitrion brand name.

Established in 1976, LPKF Laser & Electronics manufactures laser systems used in circuit board prototyping, microelectronics fabrication, solar panel scribers, laser plastic welding systems and recently added a foundry service for thin glass substrates used in electronics packaging. LPKF’sworldwide headquarters is located in Hannover, Germany and its North American headquarters resides in Portland, OR.

A NIMS-led research group succeeded in developing a high-quality diamond cantilever with among the highest quality (Q) factor values at room temperature ever achieved. The group also succeeded for the first time in the world in developing a single crystal diamond microelectromechanical systems (MEMS) sensor chip that can be actuated and sensed by electrical signals. These achievements may popularize research on diamond MEMS with significantly higher sensitivity and greater reliability than existing silicon MEMS.

Micrographs of the diamond MEMS chip developed through this research and one of the diamond cantilevers integrated into the chip. Credit: NIMS

MEMS sensors–in which microscopic cantilevers (projecting beams fixed at only one end) and electronic circuits are integrated on a single substrate–have been used in gas sensors, mass analyzers and scanning microscope probes. For MEMS sensors to be applied in a wider variety of fields, such as disaster prevention and medicine, their sensitivity and reliability need to be further increased. The elastic constant and mechanical constant of diamond are among the highest of any material, making it promising for use in the development of highly reliable and sensitive MEMS sensors. However, three-dimensional microfabrication of diamond is difficult due to its mechanical hardness. This research group developed a “smart cut” fabrication method which enabled microprocessing of diamond using ion beams and succeeded in fabricating a single crystal diamond cantilever in 2010. However, the quality factor of the diamond cantilever was similar to that of existing silicon cantilevers because of the presence of surface defects.

The research group subsequently developed a new technique enabling atomic-scale etching of diamond surfaces. This etching technique allowed the group to remove defects on the bottom surface of the single crystal diamond cantilever fabricated using the smart cut method. The resulting cantilever exhibited Q factor values–a parameter used to measure the sensitivity of a cantilever–greater than one million; among the world’s highest. The group then formulated a novel MEMS device concept: simultaneous integration of a cantilever, an electronic circuit that oscillates the cantilever and an electronic circuit that senses the vibration of the cantilever. Finally, the group developed a single crystal diamond MEMS chip that can be actuated by electrical signals and successfully demonstrated its operation for the first time in the world. The chip exhibited very high performance; it was highly sensitive and capable of operating at low voltages and at temperatures as high as 600°C.

These results may expedite research on fundamental technology vital to the practical application of diamond MEMS chips and the development of extremely sensitive, high-speed, compact and reliable sensors capable of distinguishing masses differing by as light as a single molecule.

Flexible and printed electronics innovations and autonomous mobility sensors will take center stage as more than 700 attendees gather for 120 market and technical presentations, 70 exhibits and four short courses at the co-located FLEX 2019 and MEMS & Sensors Technical Congress (MSTC) in Monterey, California, February 18-21, 2019. Click here to register for both events.

Themed Electronics Out of the Box, FLEX 2019, the Flexible & Printed Electronics Conference and Exhibition, will highlight new form factors enabled by advances in flexible, printed and hybrid electronics. MSTC, themed Sensor Systems Enabling Autonomous Mobility, will showcase sensor innovations and emerging applications. The events cover a broad span of new applications and innovation drivers in key markets such as SMART Medtech, SMART Transportation and Internet of Things (IoT).

FLEX and MSTC will unite in the exhibition, opening keynotes, panel discussion, networking events and short courses, with the events featuring separate technical sessions. Attendees will connect with a broad group of subject matter experts and industry innovators.

FLEX 2019 and MSTC 2019 at a Glance

FLEX 2019 technical sessions will spotlight innovations in flexible and printed electronics products, equipment and materials as well as unique electronics applications they deliver – from new battery structures and antennas to bio-medical devices. Follow FLEX 2019 on Twitter: #FLEX2019 and @flextechnews

MSTC 2019 sessions will highlight wearables, point-of-care medical devices, food delivery, agriculture platforms, remote monitoring systems and other applications with stringent sensor, data storage, processing and transmission requirements. Follow MSTC on Twitter: #MSTC2019 and @MEMSGroup

“Advances in flexible electronics, MEMS and sensors have immediate, positive impact on the world we live in,” said Ajit Manocha, president and CEO of SEMI. “FLEX 2019 and MSTC 2019 are the ideal platforms to showcase how sensors harness the power of data and improve our lives.”

The special poster session highlighting student projects related to flexible electronics or MEMS and sensors will be back by popular demand. The posters are evaluated for their scientific methods, command of the subject matter and usefulness of the ideas to the industry. Winners receive cash awards, plaques and recognition at the annual FLEXI Awards ceremony.

Keynotes include:

  • Ford Motor Company – The changing automotive sensor landscape
  • John Deere Electronics Solutions – Autonomy in agriculture to solve challenges in space, form factor, power availability and harsh operating conditions
  • Rogers Research, Northwestern University –  The emergence of diverse, novel classes of biocompatible electronic and microfluidic systems with skin-like physical properties to enable innovations in sports and fitness
  • STMicroelectronics – Profiles of new precision sensors for industrial applications, including combination sensors, specialized sensors, and complete inertial modules

A team of researchers at the New York University Tandon School of Engineering and NYU Center for Neural Science has solved a longstanding puzzle of how to build ultra-sensitive, ultra-small electrochemical sensors with homogenous and predictable properties by discovering how to engineer graphene structure on an atomic level.

Finely tuned electrochemical sensors (also referred to as electrodes) that are as small as biological cells are prized for medical diagnostics and environmental monitoring systems. Demand has spurred efforts to develop nanoengineered carbon-based electrodes, which offer unmatched electronic, thermal, and mechanical properties. Yet these efforts have long been stymied by the lack of quantitative principles to guide the precise engineering of the electrode sensitivity to biochemical molecules.

Davood Shahrjerdi, an assistant professor of electrical and computer engineering at NYU Tandon, and Roozbeh Kiani, an assistant professor of neural science and psychology at the Center for Neural Science, Faculty of Arts and Science, have revealed the relationship between various structural defects in graphene and the sensitivity of the electrodes made of it. This discovery opens the door for the precise engineering and industrial-scale production of homogeneous arrays of graphene electrodes. The researchers detail their study in a paper published today in the journal Advanced Materials.

Graphene is a single, atom-thin sheet of carbon. There is a traditional consensus that structural defects in graphene can generally enhance the sensitivity of electrodes constructed from it.  However, a firm understanding of the relationship between various structural defects and the sensitivity has long eluded researchers. This information is particularly vital for tuning the density of different defects in graphene in order to achieve a desired level of sensitivity.

“Until now, achieving a desired sensitivity effect was akin to voodoo or alchemy — oftentimes, we weren’t sure why a certain approach yielded a more or less sensitive electrode,” Shahrjerdi said. “By systematically studying the influence of various types and densities of material defects on the electrode’s sensitivity, we created a physics-based microscopic model that replaces superstition with scientific insight.”

In a surprise finding, the researchers discovered that only one group of defects in graphene’s structure — point defects — significantly impacts electrode sensitivity, which increases linearly with the average density of these defects, within a certain range. “If we optimize these point defects in number and density, we can create an electrode that is up to 20 times more sensitive than conventional electrodes,” Kiani explained.

These findings stand to impact both the fabrication of and applications for graphene-based electrodes. Today’s carbon-based electrodes are calibrated for sensitivity post-fabrication, a time-consuming process that hampers large-scale production, but the researchers’ findings will allow for the precise engineering of the sensitivity during the material synthesis, thereby enabling industrial-scale production of carbon-based electrodes with reliable and reproducible sensitivity.

Currently, carbon-based electrodes are impractical for any application that requires a dense array of sensors: The results are unreliable due to large variations of the electrode-to-electrode sensitivity within the array. These new findings will enable the use of ultra-small carbon-based electrodes with homogeneous and extraordinarily high sensitivities in next-generation neural probes and multiplexed “lab-on-a-chip” platforms for medical diagnostics and drug development, and they may replace optical methods for measuring biological samples including DNA.

Most lasers have only one color. All the photons it emits have exactly the same wavelength. However, there are also lasers whose light is more complicated. If it consists of many different frequencies, with equal intervals in between, just like the teeth of a comb, it is referred to as a “frequency comb”. Frequency combs are perfect for detecting a variety of chemical substances.

At TU Wien (Vienna), this special type of laser light is now used to enable chemical analysis on tiny spaces – it is a millimeter-format chemistry lab. With this new patent-pending technology, frequency combs can be created on a single chip in a very simple and robust manner. This work has now been presented in the journal “Nature Photonics“.

A comb with a Nobel Prize

Frequency combs have been around for years. In 2005, the Nobel Prize for Physics was awarded for this. “The exciting thing about them is that it is relatively easy to build a spectrometer with two frequency combs,” explains Benedikt Schwarz, who heads the research project. “It is possible to make use of beats between different frequencies, similar to those that occur in acoustics, if you listen to two different tones with similar frequency. We use this new method, because it does not require any moving parts and allows us to develop a miniature chemistry lab on a millimetre scale.”

At the Vienna University of Technology, frequency combs are produced with quantum cascade lasers. These special lasers are semiconductor structures that consist of many different layers. When electrical current is sent through the structure, the laser emits light in the infrared range. The properties of the light can be controlled by tuning the geometry of the layer structure.

“With the help of an electrical signal of a specific frequency, we can control our quantum cascade lasers and make them emit a series of light frequencies, which are all coupled together,” says Johannes Hillbrand, first author of the publication. The phenomenon is reminiscent of swings on a rocking frame – instead of pushing individual swings, one can make the scaffolding wobble at the right frequency, causing all the swings to oscillate in certain coupled patterns. “The big advantage of our technology is the robustness of the frequency comb,” says Benedikt Schwarz. Without this technique, the lasers are extremely sensitive to disturbances, which are unavoidable outside the lab – such as temperature fluctuations, or reflections that send some of the light back into the laser. “Our technology can be realized with very little effort and is therefore perfect for practical applications even in difficult environments. Basically, the components we need can be found in every mobile phone”, says Schwarz.

The molecular fingerprint

The fact that the quantum cascade laser generates a frequency comb in the infrared range is crucial, because many of the most important molecules can best be detected by light in this frequency range. “Various air pollutants, but also biomolecules, which play an important role in medical diagnostics, absorb very specific infrared light frequencies. This is often referred to as the optical fingerprint of the molecule, “explains Johannes Hillbrand. “So, when we measure, which infrared frequencies are absorbed by a gas sample, we can tell exactly which substances it contains.”

Measurements in the microchip

“Because of its robustness, our system has a decisive advantage over all other frequency comb technologies: it can be easily miniaturized,” says Benedikt Schwarz. “We do not need lens systems, no moving parts and no optical isolators, the necessary structures are tiny. The entire measuring system can be accommodated on a chip in millimeter format.”

This results in spectacular application ideas: one could place the chip on a drone and measure air pollutants. Chips glued to the wall could search for traces of explosive substances in buildings. The chips could be used in medical equipment to detect diseases by analyzing chemicals in the respiratory air.

The new technology has already been patented. “Other research teams are already highly interested in our system. We hope that it will soon be used not only in academic research, but also in everyday applications, “says Benedikt Schwarz.

Vertiv announced today that it has completed the purchase of the maintenance business of MEMS Power Generation (MEMS), a privately-owned company headquartered in the United Kingdom that specializes in temporary power solutions. This marks the third acquisition for Vertiv, and is consistent with the company’s growth strategy. MEMS will now focus entirely on its generator rentals solutions business.

“The addition of the MEMS maintenance business is a natural fit for our existing U.K. business and we welcome MEMS’ more than 160 contract customers that we now have the opportunity to serve,” said Rob Johnson, Vertiv chief executive officer. “By strengthening our capability in generator maintenance, and expanding our service offerings in critical infrastructure in EMEA, we’re well positioned to offer customers an unmatched suite of services.”

“Since partnering with Vertiv in 2016, we continue to be impressed by the company’s vision and ability to execute strategic deals that serve to expand the business in key growth areas,” said Platinum Equity Partner Jacob Kotzubei. “The Vertiv management team continues to make smart investments to grow its global business and position the company for continued success.”

The 160 MEMS contract customers in the U.K. range from data centers to hospitals and universities to industrial companies and utilities. Vertiv will service the newly acquired MEMS customers with the Vertiv U.K. service team.

Vertiv and MEMS Power Generation closed the sale on Nov. 30, 2018. MEMS transferred all its service and maintenance contracts to Vertiv at that time.

Scientists from Jülich together with colleagues from Aachen and Turin have produced a memristive element made from nanowires that functions in much the same way as a biological nerve cell. The component is able to both save and process information, as well as receive numerous signals in parallel. The resistive switching cell made from oxide crystal nanowires is thus proving to be the ideal candidate for use in building bioinspired “neuromorphic” processors, able to take over the diverse functions of biological synapses and neurons.

Computers have learned a lot in recent years. Thanks to rapid progress in artificial intelligence they are now able to drive cars, translate texts, defeat world champions at chess, and much more besides. In doing so, one of the greatest challenges lies in the attempt to artificially reproduce the signal processing in the human brain. In neural networks, data are stored and processed to a high degree in parallel. Traditional computers on the other hand rapidly work through tasks in succession and clearly distinguish between the storing and processing of information. As a rule, neural networks can only be simulated in a very cumbersome and inefficient way using conventional hardware.

Systems with neuromorphic chips that imitate the way the human brain works offer significant advantages. Experts in the field describe this type of bioinspired computer as being able to work in a decentralised way, having at its disposal a multitude of processors, which, like neurons in the brain, are connected to each other by networks. If a processor breaks down, another can take over its function. What is more, just like in the brain, where practice leads to improved signal transfer, a bioinspired processor should have the capacity to learn.

“With today’s semiconductor technology, these functions are to some extent already achievable. These systems are however suitable for particular applications and require a lot of space and energy,” says Dr. Ilia Valov from Forschungszentrum Jülich. “Our nanowire devices made from zinc oxide crystals can inherently process and even store information, as well as being extremely small and energy efficient,” explains the researcher from Jülich’s Peter Grünberg Institute.

For years memristive cells have been ascribed the best chances of being capable of taking over the function of neurons and synapses in bioinspired computers. They alter their electrical resistance depending on the intensity and direction of the electric current flowing through them. In contrast to conventional transistors, their last resistance value remains intact even when the electric current is switched off. Memristors are thus fundamentally capable of learning.

In order to create these properties, scientists at Forschungszentrum Jülich and RWTH Aachen University used a single zinc oxide nanowire, produced by their colleagues from the polytechnic university in Turin. Measuring approximately one ten-thousandth of a millimeter in size, this type of nanowire is over a thousand times thinner than a human hair. The resulting memristive component not only takes up a tiny amount of space, but also is able to switch much faster than flash memory.

Nanowires offer promising novel physical properties compared to other solids and are used among other things in the development of new types of solar cells, sensors, batteries and computer chips. Their manufacture is comparatively simple. Nanowires result from the evaporation deposition of specified materials onto a suitable substrate, where they practically grow of their own accord.

In order to create a functioning cell, both ends of the nanowire must be attached to suitable metals, in this case platinum and silver. The metals function as electrodes, and in addition, release ions triggered by an appropriate electric current. The metal ions are able to spread over the surface of the wire and build a bridge to alter its conductivity.

Components made from single nanowires are, however, still too isolated to be of practical use in chips. Consequently, the next step being planned by the Jülich and Turin researchers is to produce and study a memristive element, composed of a larger, relatively easy to generate group of several hundred nanowires offering more exciting functionalities.