MEMS microphones

Part 2 of 2-part series on MSEC 2019 highlights. Read Part 1. Neural Networks on ChipTo be sure, low power is king when bringing machine learning to the sensor edge. Battery-powered, always-on sensing devices require it since frequent recharging is the death knell of any electronic product. That’s why semiconductor companies are offering new ways to conserve power.“MEMS sensor suppliers have made significant strides in the power, size and performance of their devices,” said Aspinity CEO Tom Doyle. “Yet these gains deliver only incremental power improvements to the system.”Doyle advocates a new architectural model that uses an analog neuromorphic processor to analyze all sensor data at the start of the signal chain instead of sending it downstream so power-hungry chips such as DSPs can digitize it before analysis.“The technology industry wants to take advantage of the many benefits of always-on sensing applications,” said Doyle. “Before we can reach mass proliferation, however, we need to resolve the power issues that are deal-breakers for some applications. We believe the answer to this challenge is architectural. All the data gathered by always-on sensing systems is analog in nature, yet as soon as it’s captured, it’s digitized immediately for analysis. Determining which data is important up front eliminates the digitization and processing of irrelevant data so that voice-first devices such as smart speakers and wearables/hearables can run for long periods of time without requiring battery recharge.”Syntiant CTO Jeremy Holleman agreed that on-device intelligence is the future.“Did you just fall? Is your heartrate a bit off? Deep learning provides a toolset that yields vastly superior decisions,” said Holleman. “The problem is that deep learning is computationally intensive. The answer is a neural network that performs on-device edge inferencing.”Holleman added that Syntiant’s neural decision processor was recently certified as Amazon Voice Service (AVS)-compliant for wake-word detection, making it easier to design voice control in battery-powered devices such as earbuds and wearables.MSEC Technology Showcase WinnerWith the groundswell of interest in intelligence at the edge, it was no surprise that Cartesiam won top honors among all competitors in the MSEC Technology Showcase for its NanoEdge AI, software that brings AI to the edge of the signal chain, making it easier for designers to create intelligent objects that can learn and understand.“Unlike other AI algorithmic technologies for sensing devices, NanoEdge enables both learning and inference at the edge, providing accurate and adaptive intelligence,” said Cartesiam Managing Director and Co-founder Marc Dupaquier, who accepted the award. “It’s also the only tool of its kind that does not require data scientists on board for implementation, which saves a tremendous amount of money. Our clients can build a machine learning library and embed it into their own code within weeks to realize the same caliber of unsupervised neural network that was once the exclusive domain of AI cloud vendors.”MSIG 2019 Hall of FameAt this year’s conference, MSIG Director Carmelo Sansone recognized two longtime contributors to the commercialization of MEMS and sensors: Peter G. Hartwell, Ph.D., chief technology officer at InvenSense, a TDK group company; and Thomas Kenny, professor and senior associate dean of engineering at Stanford University.Hartwell leads technology strategy and the InvenSense advanced technology research group. He has more than 25 years’ experience commercializing silicon MEMS products, including advanced sensors and actuators, and developing MEMS testing techniques.Kenny’s academic accomplishments include authoring or co-authoring more than 250 scientific papers and holding 50 issued patents. He has also advised more than 50 graduated Ph.D. students from Stanford.MSEC 2020Mark your calendar for next year’s MSEC, October 12-14, at Coronado Island Marriott Resort Spa in Coronado, Calif. Get updates from MSIG on MSEC and other upcoming events including MSTC 2020.Stay in Touch with MSIGMEMS Sensors Industry Group (MSIG), a SEMI Strategic Association Partner, is the industry association representing the global MEMS and sensors supply chain. To learn how MSIG enables professionals in the MEMS and sensors industry to innovate, address common challenges and accelerate business results, visit us today.Connect with MSIG on Twitter and LinkedIn. Subscribe to SEMI Blog: Technology and Trends.Maria Vetrano is a public relations consultant at SEMI.

Stefano Zanella, Head of Automotive, Industrial and Location Businesses, TDK InvenSense will present at next month’s SEMICON Taiwan (September 18-20, 2019 in Taipei City, Taiwan). SEMI Taiwan’s Emmy Yi spoke with Stefano for a preview of his talk.SEMI: What macro market trends are driving automotive manufacturers to increase the variety and volume of MEMS sensors in cars?Zanella: The car world is changing. Consumers increasingly view car ownership as less desirable, yet the number of miles traveled and of hours spent in a car are rising steadily. At the same time, cars are changing profoundly, and the pace of change is rapid. To thrive in this new world, automakers are becoming transportation enablers and providers.Many vehicles today autonomously interact with humans and the world around them, operate with less or no human control, and are powered by electric batteries. MEMS sensors – which mimic and augment the five human senses – are front and center in these advancements.Unlike other types of sensors – such as cameras, radar and GNSS/GPSS – MEMS gyroscopes are functional in every environment. Gyroscopes, as well as accelerometers, can supplement those other sensors when they are not available and boost the accuracy of their outputs when they are available. Both camera stabilization and dead reckoning when GNSS is unavailable are good examples of the latter. Other prevalent sensors include MEMS microphones, used to capture voice commands, ultrasonic sensors, which can be leveraged for parking and gesture recognition, and fingerprint sensors, which can improve car security.SEMI: How can automakers stay competitive in this changing landscape?Zanella: Automakers can future-proof their relevance in the transportation market in several ways. By embracing consumer migration toward ride-sharing over car ownership, many are transforming from manufacturers to mobility providers. Carmakers that invest in ride-sharing and other modes of transportation (e.g., scooters) can sustain their profitability, even if the number of vehicles sold eventually shrinks or simply doesn’t grow as much as anticipated.Automakers will need to pursue new avenues of product differentiation. Traditionally, automakers have kept performance and aesthetics to themselves by owning the engine and the body design of the car, leaving nearly everything else to suppliers. Autonomous driving and electrification, however, are pushing automakers to own the battery pack and the autonomous driving software stack.While we are just beginning to see standardization in battery packs, automakers are likely to own the autonomous driving stack for many years to come. Automakers that offer cars with highly functional and efficient batteries and driving stacks stand to gain market share.Automotive infotainment systems will become increasingly crucial as autonomous driving turns everyone into a passenger. Audio subsystem providers such as Harman Kardon, Bose, and Bang Olufsen, for example, jockeyed for attention at the most recent Geneva Motor Show, demonstrating sophisticated surround-sound systems that rival premium-quality home audio setups.With more and more consumers using voice interfaces to interact with devices in the home, drivers are less willing to accept spotty accuracy in the car. Hence, automakers are using more higher-performing MEMS microphones to accurately capture voice commands. This will come as a relief to those of us who routinely yell at our steering wheels while using voice command to try to call home. Demand for higher quality infotainment systems has prompted some automotive OEMs to own the entire infotainment system and work directly with sensor and chipmakers, a level of intimacy that gives automakers a chance to tune sensor and chip development to their own needs. This tighter relationship also positions device suppliers to forge more direct links with drivers.SEMI: Which MEMS sensors are particularly important to tomorrow’s automobiles and why?Zanella: For many years the automotive industry has been integrating more electronics into cars to improve safety, advance the driver and passenger experience, and, more recently, power the car. As vehicles rely less on human control, automakers must replace the senses of the driver with something else. That something else is a bunch of sensors, microphones, cameras, radar and LIDAR to replace vision and hearing.Since MEMS sensors such as accelerometers, gyroscopes and pressure sensors are much more robust than other types of sensors to operate in snow, rain and darkness and other imperfect environments, automakers use them to ensure that the vehicle never gets lost when other sensors and/or the GPS/GNSS signal become unavailable in tunnels or urban canyons. Gyros help determine direction, accelerometers velocity and distance driven, and pressure sensors height, such as when taking a fork on a multi-level highway. At the same time, fingerprint sensors, ultrasonic parking sensors, and temperature sensors are improving convenience, safety and security for the car’s occupants. Automakers increasingly use inertial and environmental sensors, MEMS microphones, fingerprint sensors, and vision/imaging sensors to augment or replace the five human senses on which car drivers have relied for over 100 years. Source: TDK InvenSense SEMI: To what degree can MEMS sensors enable automotive security?Zanella: MEMS sensors are used widely to enhance security today. Some of their mechanisms are easy to understand while some are unexpected. For instance, ultrasonic fingerprint sensors can authenticate the driver of a vehicle to prevent car theft or something less onerous, like a teenage driver taking the car out without permission.Accelerometers and gyroscopes can prevent a new type of spoof on keyless entry systems. Imagine that you are very close to your vehicle. Your car senses the remote control in your pocket and automatically opens the doors when you pull the handle. Now suppose that your car is parked on the street, not far from your house. You leave the remote control home, and the car doesn’t sense the proximity of the remote control. Great! No one can enter your car, unless ... a thief has a big signal amplifier that makes your car think that the keyless entry device is next to the car. In this case, what can an automaker do? Add an accelerometer that restricts the keyless device from broadcasting the entry signal unless you are walking to the car with the device on your person.SEMI: What would you like SEMICON Taiwan attendees to take away from your presentation?Zanella: I would like them to embrace the transformations afoot in the automotive market as well as their associated design challenges since, by overcoming these hurdles, they can offer significant societal benefits such as safer and cleaner transportation. At the same time, these transformations mean significant opportunities for semiconductor industry revenue growth. And while design-to-delivery cycles in automotive are longer than in consumer and mobile, the automotive market supports higher-value devices as well as the chance to fold dozens of MEMS sensors into a single model.To paraphrase Lord Kelvin: If you can’t sense it, you can’t manage it. As suppliers of many key technologies that make intelligent transportation possible, the MEMS sensors industry is in an excellent position to help automakers manage the many challenges ahead.Stefano Zanella, Ph.D., is Head of Automotive, Industrial and Location Businesses at TDK InvenSense, where he brings MEMS sensors (including accelerometers, gyroscopes and microphones) and location solutions to the automotive and industrial markets. Zanella holds an MS and a Ph.D. in Electrical Engineering from the University of Padova, Padova, Italy as well as MBAs from both the UC Berkeley Haas School of Business and from Columbia University.He will present MEMS Sensors Enabling the Smart Car Revolution on Wednesday, September 18, 2019, at SEMICON Taiwan at 1F 4F, Taipei Nangang Exhibition Center, Taipei City, Taiwan. Register today and save 20% to learn how MEMS sensors are transforming the human experience with cars.Connect with Stefano Zanella at SEMICON Taiwan or via LinkedIn. You can also get more information on TDK’s automotive solutions and application guides online.Interested in engaging with the MEMS sensors supply chain? SEMI MEMS Sensors Industry Group is a technology community that enables professionals in the MEMS and sensors industry to innovate, address common challenges and accelerate business results.Emmy Yi is a marketing specialist at SEMI Taiwan.

Air pollution is one of the grand challenges facing the entire planet — from the wealthiest nations to the least developed. The World Health Organization reports that nine out of 10 people breathe air containing high levels of pollutants, and that polluted air takes over seven million lives annually through stroke, heart disease and respiratory ailments.As a result, the world is thirsty for reliable, high-performing chemical and environmental sensors that can provide previously unavailable real-time awareness of environmental conditions. On one level, this seems like a relatively simple step, given that smartphones are already equipped with miniaturized sensing technologies that can monitor our living environment and activities.While highly desirable, embedding air pollution sensors in common mobile and wearable devices has not been feasible previously because the necessary trade-offs between high performance and miniaturization have made it impossible.This situation drove a CEA-Leti team to develop a novel generation of fully integrated optical chemical sensors that leverage MEMS technologies. The team successfully merged multiple functionalities on the same chip, using integrated optics and photonics, fluidics, acoustics and electromechanical transduction. How did the team overcome significant technical obstacles to design a proof-of-concept device that senses multiple environmental pollutants — housed in a minimal hardware footprint?Advancing Chemical Sensor Capabilities with Silicon Featuring high selectivity, real-time performance, and fully reversible capabilities, optical chemical sensors are perfect candidates for industrial, environmental and biomedical applications. Consequently, in recent years, worldwide R D initiatives have invested substantial effort to improve them.R D programs have focused particularly on the mid-infrared (Mid-IR) wavelength range (2.5 - 12 µm) — also known as the molecule fingerprint region, which provides a unique combination of fundamental absorption order-of-magnitude bands and unambiguous identification of specific chemicals. A multitude of molecules generate strong and distinct absorption lines in the Mid-IR, providing a foundation for accurate spectroscopic detection. Traditionally, however, these sensors have required large and expensive lenses for infrared (IR) light, making them too big and costly for resource-constrained wearables and mobile devices.Fortunately, recent advances in integrated silicon photonics and quantum cascade laser (QCL) technologies have spurred investigation of new chemical sensor architectures. Richard Soref, a research professor at the University of Massachusetts Boston’s department of engineering, introduced the extension of Near-IR technology into the longer-wave Mid-IR infrared region in 2006. Soref’s concept showed that highly sensitive and selective gas sensors could be fabricated on planar substrates at low cost by co-integrating silicon MEMS, group IV photonics, and specifically designed III-V hetero-structures.While this approach showed promise, it preceded the widespread availability of most mobile devices and wearables. Foreseeing today’s proliferation of those devices, CEA-Leti developed the different building blocks required to implement these concepts in real devices.A New Concept of Integrated OpticsLeveraging these interesting findings, the institute developed a new combination of integrated optics and multiple sensor functions on a single chip: QCL sources, a photo-acoustic (PA) cell, and a mid-IR photonic integrated circuit (PIC) combiner. Their integration on a planar substrate (Figure 1) helped to achieve higher performance, new capabilities, and higher reliability at lower cost, all in a smaller package (less than a 1 cm3 or smaller than a 1-cent coin) with reduced weight and power consumption (less than 100 mJ per measurement). Figure 1: Fully integrated optical sensor (Courtesy: CEA Leti) This configuration represents a multi-gas-detection enabler. The PIC replaces costly, fragile discrete optics while the PA detector uses a MEMS microphone to replace bulky multi-pass cells.PA spectroscopy is among the most sensitive techniques available for monitoring chemical emissions or detecting gas traces. It relies on excitation of the chemical with a pulsed light source emitting at the absorption wavelengths of such molecules. The relaxation process creates local periodic variations of the temperature, resulting in stationary pressure waves, which high-performance microphones can detect.This new generation of devices, fully fabricated on silicon, shows performance comparable with state-of-the-art systems, with the huge bonus of small size and power efficiency that work well for mobile and wearable electronics. By supporting integration onto common technological platforms, such as on-chip photoacoustic sensors, researchers have successfully realized these miniaturized and cost-effective Mid-IR photonic devices in silicon. Mobile device and wearables manufacturers can now take advantage of manufacturable integrated devices for applications that are highly sensitive to size, performance and cost. Adding gas sensing to mobile devices and wearables is now very feasible.For more information on chemical sensing at CEA-Leti, please visit or contact: http://www.leti-cea.com/cea-tech/leti/englishCEA-Leti is an active member of SEMI-MEMS Sensors Industry Group. The technology research institute, along with Fraunhofer and imec, recently joined SEMI’s family as a Strategic Association Partner under a memorandum of understanding (MOU). Under this agreement, CEA-Leti will work with SEMI to advance technology roadmaps, industry standards and cutting-edge technologies including Internet of Things (IoT), artificial intelligence (AI) and machine learning that enable new capabilities across healthcare, automotive and other electronics manufacturing ecosystems. Sergio Nicoletti has more than 20 years of experience in micro and nanofabrication, including magnetic, superconducting and chemical sensing devices and technologies. Having joined CEA-Leti in 2006 as project manager for optical sensing devices used in chemical detection, Nicoletti is currently business development manager at the institute.Previous positions include research and project management at CNR-IMM (Bologna, Italy) and at Hitachi Global Storage Technologies. Nicoletti was also a visiting scientist at HGST (San Jose, Calif.), where he worked on magnetic recording-head devices.Nicoletti holds more than 20 patents and has more than 70 publications in peer-reviewed journals. In 2016, he was appointed coordinator of the European H2020 project MIRPHAB and is director of the project’s pilot line.Nicoletti received his Ph.D. in physics, with a focus on HTc superconducting devices, from Université Joseph Fourier (Grenoble, France). References“Photoacoustic cell on silicon for mid-infrared QCL-based spectroscopic analysis,” JG Coutard, A Glière, JM Fedeli, O Lartigue, J Skubich, G Aoust, A Teulle, T Strahl, S Nicoletti, M Carras, L Duraffourg. Proceedings Volume 10931, MOEMS and Miniaturized Systems XVIII; 109310V (2019) https://doi.org/10.1117/12.2506514“Miniaturization of mid-IR sensors on Si: challenges and perspectives,” S Nicoletti, JM Fédéli, M Fournier, P Labeye, P Barritault, A Marchant, A Glière, A Teulle, J Coutard, L Duraffourg - Silicon Proceedings Volume 10923, Silicon Photonics XIV; 109230H (2019) https://doi.org/10.1117/12.2506759

2017 was a good year for the MEMS and sensors business, and that upward trend should continue. We forecast extended strong growth for the sensors and actuators market, reaching more than $100 billion in 2023 for a total of 185 billion units. Optical sensors, especially CMOS image sensors, will have the lion’s share with almost 40 percent of market value. MEMS will also play an important role in that growth: During 2018–2023, the MEMS market will experience 17.5 percent growth in value and 26.7 percent growth in units, with the consumer market accounting for more than 50 percent(1) share overall. Evolution of SensorsSensors were first developed and used for physical sensing: shock, pressure, then acceleration and rotation. Greater investment in R D spurred MEMS’ expansion from physical sensing to light management (e.g., micromirrors) and then to uncooled infrared sensing (e.g., microbolometers). From sensing light to sensing sound, MEMS microphones formed the next wave of MEMS development. MEMS and sensors are entering a new and exciting phase of evolution as they transcend human perception, progressing toward ultrasonic, infrared and hyperspectral sensing.Sensors can help us to compensate when our physical or emotional sensing is limited in some way. Higher-performance MEMS microphones are already helping the hearing-impaired. Researchers at Arizona State University are among those developing cochlear implants — featuring piezoelectric MEMS sensors — which may one day restore hearing to those with significant hearing loss. The visually impaired may take heart in knowing that researchers at Stanford University are collaborating on silicon retinal implants. Pixium Vision began clinical trials in humans in 2017 with its silicon retinal implants.It’s not science fiction to think that we will use future generations of sensors for emotion/empathy sensing. Augmenting our reality, such sensing could have many uses, perhaps even aiding the ability of people on the autism spectrum to more easily interpret the emotions of others.Through my years in the MEMS industry, I have identified three distinct eras in MEMS’ evolution: The “detection era” in the very first years, when we used simple sensors to detect a shock. The “measuring era” when sensors could not only sense and detect but also measure (e.g., a rotation). The “global-perception awareness era” when we increasingly use sensors to map the environment. We conduct 3D imaging with Lidar for autonomous vehicles. We monitor air quality using environmental sensors. We recognize gestures using accelerometers and/or ultrasonics. We implement biometry with fingerprint and facial recognition sensors. This is possible thanks to sensor fusion of multiple parameters, together with artificial intelligence. Numerous technological breakthroughs are responsible for this steady stream of advancements: new sensor design, new processes and materials, new integration approaches, new packaging, sensor fusion, and new detection principles.Global Awareness SensingThe era of global awareness sensing is upon us. We can either view global awareness as an extension of human sensing capabilities (e.g., adding infrared imaging to visible) or as beyond-human sensing capabilities (e.g., machines with superior environmental perception, such as Lidar in a robotic vehicle). Think about Professor X in Marvel’s universe, and you can imagine how human perception could evolve in the future! Some companies envisioned global awareness from the start. Movea (now part of TDK InvenSense), for example, began their development with inertial MEMS. Others implemented global awareness by combining optical sensors such as Lidar and night-vision sensors for robotic cars. A third contingent grouped environmental sensors (gas, particle, pressure, temperature) to check air quality. The newest entrant in this group, the particle sensor, could play an especially important role in air-quality sensing, particularly in wearable devices.Driven by increasing societal concern over mounting evidence of global air-quality deterioration, air pollution has become a major topic in our society. Studies show that there is no safe level of particulates. Instead, for every increase in concentration of PM10 or PM2.5 inhalable particles in the air, the lung cancer rate is rising proportionately. Combining a particle sensor with a mapping application in a wearable could allow us to identify the locations of the most polluted urban zones.The Need for Artificial Intelligence To realize global awareness, we also need artificial intelligence (AI), but first, we have challenges to solve. Activity tracking, for example, requires accurate live classification of AI data. Relegating all AI processing to a main processor, however, would consume significant CPU resources, reducing available processing power. Likewise, storing all AI data on the device would push up storage costs. To marry AI with MEMS, we must do the following: Decouple feature processing from the execution of the classification engine to a more powerful external processor. Reduce storage and processing demands by deploying only the features required for accurate activity recognition. Install low-power MEMS sensors that can incorporate data from multiple sensors (sensor fusion) and enable pre-processing for always-on execution. Retrain the model with system-supported data that can accurately identify the user’s activities. There are two ways to add AI and software in mobile and automotive applications. The first is a centralized approach, where sensor data is processed in the auxiliary power unit (APU) that contains the software. The second is a decentralized approach, where the sensor chip is localized in the same package, close to the software and the AI (in the DSP for a CMOS image sensor, for example). Whatever the approach, MEMS and sensors manufacturers need to understand AI, although they are unlikely to gain much value at the sensor-chip level.Heading to an Augmented WorldWe have achieved massive progress in sensor development over the years and are now reaching the point when sensors can mimic or augment most of our perception: vision, hearing, touch, smell and even emotion/empathy as well as some aesthetic senses. We should realize that humans are not the only ones to benefit from these developments. Enhanced perception will also allow robots to help us in our daily lives (through smart transportation, better medical care, contextually aware environments and more). We need to couple smart sensors’ development with AI to further enhance our experiences with the people, places and things in our lives.About the authorWith almost 20 years’ experience in MEMS, sensors and photonics applications, markets, and technology analyses, Dr. Eric Mounier provides in-depth industry insight into current and future trends. As a Principal Analyst, Technology Markets, MEMS Photonics, in the Photonics, Sensing Display Division, he contributes daily to the development of MEMS and photonics activities at Yole Développement (Yole). He is involved with a large collection of market and technology reports, as well as multiple custom consulting projects: business strategy, identification of investment or acquisition targets, due diligence (buy/sell side), market and technology analyses, cost modeling, and technology scouting, etc.Previously, Mounier held R D and marketing positions at CEA Leti (France). He has spoken in numerous international conferences and has authored or co-authored more than 100 papers. Mounier has a Semiconductor Engineering Degree and a PhD in Optoelectronics from the National Polytechnic Institute of Grenoble (France).Mounier is a featured speaker at SEMI-MSIG European MEMS Sensors Summit, September 20, 2018 in Grenoble, France. (1) Source: Status of the MEMS Industry report, Yole Développement, 2018