Albert Camus in one of his famous allegorical novels “The Plague” described how the population of a small city became confined and cut off from the external world after a resurgence of a plague epidemic and the effects that it had on peoples’ attitudes. Sounds familiar? During the current pandemic, though, while attitudes have indeed changed, at least people remain (socially) connected on a global scale, despite physical distancing. And for that, technology and digitalization have played the most significant role.
One of those technologies, MEMS, has brought a sensing revolution to consumer markets. MEMS microphones in every smartphone and tablet, together with CMOS image sensors, allow people to see and hear each other everywhere in the world. Initially used to manufacture miniature devices for defense and automotive applications, MEMS are now ubiquitous. Global MEMS sensor revenue was US$11.5 billion in 2019, and Yole Développement (Yole) expects it to reach almost US$17.7 billion in 2025, at a 7.4% CAGR over this period, according to their “Status of the MEMS Industry 2020” report.
The market continues to be driven in 2021, with various trends and applications increasingly gaining momentum. For instance, MEMS-based environmental hubs and gas sensors are becoming ever more sought-after, since people’s perception of their immediate environment has changed. The population cares more about the air they breathe, both inside houses but also outside due to pollution. Furthermore, it is believed that aerosol transmission, as monitored by exhaled CO2, is associated with the spread of COVID-19, which makes gas sensors ever more relevant in the current context.
But it is not only peoples’ perception about their personal health that is changing. Healthcare organizations have, in general, been transforming during the past years, with COVID-19 accelerating the pace towards a more patient-centric approach and the need for remote patient monitoring: more telehealth, more point-of-care devices, and more wearables. There is a transition to a consumer healthcare market, with wearables sold over the counter and without prescription having some medical-like functionalities (for example Apple Watch, Oura Ring). While these are not considered pure medical devices, they can track peoples’ temperature and blood pressure and even detect falls. This creates many opportunities in the wearables market, as well as for the integrated MEMS sensors, such as pressure, inertial, microphones, thermopiles, etc.
There is also a huge wave of interest in voice applications. Since a couple of years ago, voice as a human-machine interface is becoming popular. The world is moving towards a Voice Internet of Things (VIoT) with voice/virtual personal assistants (VPA) acquiring more skills, becoming more intelligent and useful. This, in turn, has a direct positive impact on MEMS microphones, increasing demand. Numerous companies (TDK Invensense, Infineon, etc.) keep releasing new digital MEMS microphones destined for such voice applications. Besides microphones that capture voice, microspeakers are used in these devices to deliver/output sound. Typically, balanced armature or electrodynamic microspeakers are used in consumer products, although the technology has not changed for more than 50 years. In the past few years, two companies developing MEMS-based microspeakers (USound, AudioPixels) have been trying to revolutionize this old technology by offering better form factors. USound successfully commercialized its products, and in 2020 alone, two MEMS microspeaker start-ups have sprouted (Arioso, xMEMS), proving the interest in that domain.
On another note, embedded intelligence is becoming a must: i.e., computing at the edge, which implies not only AI inference but also sometimes training are both done at the MCU level. Bosch Sensortec released such a sensor product (inertial MEMS with embedded AI) for wearables in CES 2021, and various start-ups (Syntiant, Cartesiam, Aspinity) are working on dedicated chips. Besides that, integration of CMOS-on-MEMS will thrive, as more compact intelligent sensors and associated packages will be needed. In general, embedded AI is revolutionizing existing use-cases and creating new use-cases by continuous improvement of user-experience.
Finally, all of these points discussed above have some implications for engineers across all industries. Up to now, various specific engineers (Process, Quality, Integration, Packaging, etc.) were needed to master the sensor, or the ASIC or packaging; they will indeed still be needed. But the shift towards more intelligence close to the sensors and a holistic, system-level approach creates an immediate need for more System and System Integration Engineers as well as Embedded Software/Hardware Engineers. Engineers in these categories will surely find many opportunities in the sensor industry.
