by Michael Niedermayer, Ph.D.
Group Manager, Fraunhofer Institute for Reliability and Microintegration
Almost unnoticed, microsystems are increasingly taking over essential tasks in our everyday lives. These very small devices assist doctors during operations, control the room climate, and improve the safety of automobiles. Microsystems have the capability to sense specific physical phenomena, to qualify situations, and to interact with their environment. To do this, they contain sensors for signal recording, digital circuitry for data processing, and actuators for influencing their surroundings. Several physical effects can be utilized to develop appropriate sensors. These functional components can gather data from the mechanical, thermal, magnetic, chemical, or radiant domain to transform the corresponding energy into electrical signals. Actuators convert electrical signals into energy of various physical domains to trigger events.
A multitude of properties characterize sensors and actuators. For instance, acceleration sensors for the tracking of movements are specified by parameters such as accuracy, resolution, sensitivity, noise, and dynamic range. As a result, many different sensors and actuators on the market are optimized for different environmental conditions. While many niche markets require only moderate fabrication quantities, the corresponding variety complicates the production economics.
Miniaturization and standardization are important drivers for cost reductions by applying the integration technologies of microelectronics. Hence, the category of smart sensors and actuators has emerged. These devices contain further components of interface circuitry such as amplifiers, multiplexers, and memory. Despite additional components, smart sensors and actuators offer cost savings of mass production because the more universal applicability allows for larger fabrication quantities. Based on this technical progress, smart microsystems are now developing into a new product class with a huge market potential. Besides miniaturized sensors and actuators with corresponding interface circuitry, smart microsystems contain additional functional units for self-test, calibration, and communication. In some cases, such as automotive applications, smart microsystems can be interconnected with the technical environment by wires to provide the required energy and a robust communication interface. Smart microsystems often contain their own power supply and wireless communication unit to be more universally applicable. In particular, these self-sufficient smart microsystems will revolutionize many applications. The capability of wireless communication offers the opportunity to interact with other smart microsystems and to form sensor networks. Cooperative data processing among smart microsystems in a wireless network allows taking over such tasks that a single device would not be able to do. Smart microsystems do not just sense, diagnose, and act, but also use prevision to qualify situations and communicate with their technical surroundings. While conventional microsystems only operate according to a preprogrammed scheme, smart microsystems will be able to comprehend and learn in a rudimentary way.
Since 1948, the semiconductor industry has grown enormously. The annual increase between 1980 and 2000 amounted to nearly 15%. The development of the market volume of the electronics and semiconductor industry is illustrated in Figure 1 (below). The electronics industry has doubled in proportion from 0.8% to 1.6% in comparison to the worldwide gross domestic product (GDP) of 1980 to 2000. In the same period, the revenue of semiconductors related to electronic devices even quadrupled from 5% to 21%. With an annual growth rate of roughly 6%, the electronics and semiconductor industry will expand about twice as fast as the global GDP.
Figure 1. Worldwide market trends.
The observation by Gordon Moore in 1965 that the transistor density doubles every year still applies today as Moore’s Law. Only the time base of the exponential growth has changed from 12 to 24 months. In the meantime, about 3 billion transistors can be integrated on modern microchips. According to the Semiconductor Industry Association, this trend will continue in the next decade. The development of microchips has been accompanied by a remarkable design automation that has enabled the efficient development of complex electronic systems. As a result, increasingly more functions can be implemented onto a single semiconductor chip.
Tremendous progress has also been made in the development of microsystems. Thus, sensor and actuator functionality can be combined with computing power and communication in ever smaller dimensions. The corresponding microsystem technologies have their roots in the semiconductor fabrication of microelectronic devices. In contrast to the semiconductor industry, the rather specific application requirements have led to very different fabrication steps. The resulting products are currently classified as components or subsystems, but the implementation of real microsystems has just begun. The development of microsystem technology, however, is lagging behind the dynamics of the integrated circuits. For example, in the years between 1970 and 1995, the price-performance ratio of microprocessors fell to 0.01%, while the corresponding drop for sensors amounted to only 33%.
Figure 2. Market development of wireless sensor systems.
The market development from expensive wireless sensor systems for niche markets to the advent of smart microsystems for the mass market is illustrated in Figure 2 (above). Such stepwise progress—starting in the laboratory market, gradually evolving into the industrial market until reaching the extremely cost-sensitive consumer market—can be observed for many innovations. With the technological feasibility, products with very specific requirements become available for the laboratory market. Smart sensor systems have been successfully applied in scientific research to study the habits of animals. Some initial applications can be also found in military field, such as the acoustic detection of snipers. Cost restrictions are usually of secondary importance in the laboratory market. This is changing with the entry into the mass market. While a price difference of several dollars determines the marketability of smart microsystems for the industry market, even a few cents can be significant for the consumer market. The application fields of smart microsystems in the industry market include, in particular, access control, condition monitoring, and factory automation. Smart microsystems are currently entering the consumer market. Tire pressure monitoring and heat cost allocation were among the first applications taking advantage of smart microsystems in quantities of millions.
Dr. Michael Niedermayer is the head of the Technology-Oriented Design Methods research group in the Department of System Design and Integration at the Fraunhofer Institute for Reliability and Microintegration. He holds Ph.D. degrees in both electrical engineering and economics from the Technical University of Berlin. Michael Niedermayer wrote many publications and holds several patents in the field of micro system technologies. His main research activities focus on design methodologies, packaging technologies, cost modeling and wireless sensor systems.
Reprinted from Cost-Driven Design of Smart Microsystems with permission, © 2013 Artech House, Inc.