A microsystem is a miniaturized device, an assembly or a component whose components have the smallest dimensions in the range of 1 micrometer and work together as a system.
A microsystem usually consists of one or more sensors , actuators and control electronics on a substrate or chip . The size of the individual components is in the range of a few micrometers. The demarcation is to be seen to the nanosystems , which are another order of magnitude below.
The Microsystems Technology is the study of the development of microsystems and the techniques for implementation.
With regard to the term microsystem, there are no standardized terms in the English-language literature. The simple translation of micro systems is hardly used (if so, then in Europe ). More common are those from the United States coming terms microelectromechanical systems and micro opto-electromechanical systems or their catchy abbreviations MEMS and MOEMS . In Asian (primarily Japanese) publications, on the other hand, the "expanded" term micromachines can also be found .
Microsystems used to be based on semiconductor electronics, at that time the basic material ( substrate ) was usually silicon , but also gallium arsenide . The microelectronics limited to electrical components such as transistors (CPU) and capacitors (RAM). Today microsystems can also be manufactured inexpensively from plastics, and the results in the field of materials research are used for multifunctional systems. In microsystem technology , the possibilities of semiconductor materials are expanded to include mechanical, optical, chemical and / or biological components and functions.
Compared to conventional “macro systems”, microsystems offer advantages in terms of cost savings (low consumption of materials, parallel production) and efficiency (low energy and power requirements enable autonomous systems ). In addition, they offer a wide range of functions, high functional densities, and new functionality (integration of electrical and non-electrical functions). Through integration and miniaturization, “new” physical effects can be exploited, and the short information paths lead to short reaction times. In addition, they are usually more reliable than conventional systems, mainly due to the elimination of plugs and cables.
The use of microsystems is conceivable and sensible wherever sensors / actuators and electronics work together. Medical devices as well as products from the fields of safety technology, sports, life sciences and logistics can become more versatile, simple, intelligent, smaller and more powerful with the help of microsystems. A well-known example of a microsystem from research is the Millipede memory from IBM , which is not yet commercially available (as of April 2018).
One of the largest areas of application are inertial sensors (acceleration and rotation sensors). They have been mass-produced for a long time and are used, among other things, to trigger airbags , to detect the free fall of hard drives (for mobile applications) - they recognize here whether a device is in free fall so that the read head can still be of the fall can be placed in the park position - or used as position detection in digital cameras , handhelds and modern input devices for game consoles. They are also used in photo and video cameras to implement mechanical image stabilizers in order to avoid blurring of images. The sensors are also used in the field of remote-controlled models in the form of stabilization systems.
Optical applications for microsystems are, for example, components in video projectors that are used to display images (see micromirror actuator ).
Examples of microsystems from microfluidics are bubble jet print heads of modern printers or plastic lab-on-a-chip systems with integrated valve functions. Microelectrofluidic fluid systems are also known in the literature as MEFS (“microelectrofluidic systems”).
There are capacitor microphones in microsystem technology ( English MEMS microphone ), in which the electric capacity micro changing membrane directly on the silicon - wafer is etched. If the readout electronics with a preamplifier and an analog-to-digital converter are integrated directly next to the membrane on the wafer in an application-specific integrated circuit (ASIC) (mostly as components in CMOS technology) and the microphone thus has a digital output, such Devices also known as digital microphones . Such microphones are offered by suppliers such as InvenSense (division bought from Analog Devices ), Infineon , NXP Semiconductors , Omron or STMicroelectronics . Because of the small size, low power consumption , good shielding from interference and low cost production, these microphones are increasingly being installed in small mobile devices such as smart phones , headsets , hearing aids or cameras .
Loudspeakers are a relatively new area of application for microsystems. Only in the past few years has MEMS technology for loudspeakers been increasingly considered, although research was carried out on loudspeakers based on MEMS technology as early as the 1990s. The first piezoelectric MEMS loudspeaker was made in 1995 by Lee et al. presented. Further approaches come from Harradine et al. in 1996 with an electrodynamic MEMS loudspeaker and by Loeb et al. in 1999 with a patent pending electrostatic MEMS speaker. Various institutes of the Fraunhofer-Gesellschaft have been researching speakers based on MEMS since the early 2000s . The Fraunhofer ISIT and Fraunhofer IPMS have different technological approaches within various research projects, the Fraunhofer IDMT is as a development partner for the signal drive the MEMS speaker. The first MEMS loudspeakers are already available on the market. a. distributed by the company U-Sound . For the time being, the focus will be on areas of application such as in-ear headphones and hearing aids.
According to the 8th report Status of the MEMS Industry by Yole Développement, there are currently (2012) around 350 MEMS developing or producing companies for around 200 different applications, the above representing the significant volume. According to Yole, the MEMS market will grow by an average of 20% in volume and sales by 13% per year to US $ 24 billion through 2019.
Worth mentioning here are the so-called integrated manufacturers Texas Instruments , Hewlett-Packard , Analog Devices , Robert Bosch GmbH , as well as contract manufacturers ( foundries ) such as u. a. STMicroelectronics , Dalsa and X-FAB .
- Lars Voßkämper: Automation in MEMS design: coherent layout synthesis and modeling of scalable microelectromechanical structures . VDM Verlag Dr. Müller, Saarbrücken 2008, ISBN 978-3-639-04923-7 .
- James B. Angell, Stephen C. Terry Phillip W. Barth: Silicon Micromechanical Devices . In: Scientific American . 248, No. 4, April 1983, pp. 44-55.
- Crystec Technology Trading GmbH: Production systems for the manufacture of MEMS components.
- Structure and functionality of a MEMS acceleration sensor
- John Widder and Alessandro Morcelli: Design principles of MEMS microphones: - Small but good. June 11, 2015
- Cornelius T. Leondes (Ed.): MEMS / NEMS Handbook - Techniques and Application . 2006, ISBN 0-387-24520-0 .
- Invensense Buys ADI's MEMS Mic Unit dated October 15, 2013
- MEMS microphone , ITWissen.info, accessed online August 14, 2012
- St. John Dixon-Warren: Overview of MEMS microphone technologies for consumer applications , MEMS Journal, accessed August 14, 2012.
- In-ear speakers. Retrieved December 4, 2019 .
- MEMS based headphones - Fraunhofer IPMS. Retrieved December 4, 2019 .
- Yole Développement, E. Mounier: Future of MEMS: a Market & Technologies Perspective October 2014
- Digikey, Article Library: MEMS Sensors: Sustained Demand for Innovation Applications
- Status of the MEMS Industry ( Memento of the original from June 10, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , dead link