Nanett - nano system integration
network of excellence
Profoundly multi disciplinary collaboration is the key for establishing enduring international top level research and competitive innovations in the field of micro- an nanotechnologies. Under the direction of the Technische Universität Chemnitz and the Fraunhofer Institute for Electronic Nano Systems ENAS the research consortium nanett „nano system integration network of excellence” was formed to bring together the different competences of eight renowned scientific institutions in the field of applied nanotechnologies:
The strategic direction of the network is the connection of fundamental with application oriented research in the promising domains of nanotechnology and system integration technology with the aims of transferring science into applications and being an attractive, competent and solid partner for the industry. The network is one of the successful initiatives of the program “Spitzenforschung und Innovation in den Neuen Ländern“, funded by the Federal Ministry of Education and Research (BMBF). The grant of the BMBF for the whole R&D joint venture amounts 14 million Euros. The project started in November 2009 with a funding period of five years.
Smart monitoring is an emerging field today. On the one hand, it is driven by the needs of application-oriented trends like industry 4.0, smart house, ambient assisted living and smart power. Apart from that, the increasing complexity of technical systems creates a demand for automatic monitoring. On the other hand, the permanent enhancement of micro- and nanotechnologies, embedded systems and wireless communication is enabling the development of multifunctional, autonomous, highly integrated and cost-efficient smart monitoring systems. However, to bring smart monitoring systems into a wide range of applications, some critical issues have to be tackled: high precision and robustness of sensor systems, power supply and energy consumption for autonomous systems, distributed functionality for huge devices and constructions as well as production costs. Further miniaturization of components and the integration of nanotechnologies in nano systems are promising approaches for realizing these requirements. Therefore, the nano system integration network of competence – nanett – is working on these approaches, aiming to nano systems for energy efficient sensor networks.
Within the nanett consortium fluorescent nano particles are integrated in thin films. The particles can be excited by UV light. The diameter of the nanocrystals defines the emitted wavelength. Thus, tailor-made coatings of selected colors can be realized on various substrates. Together with piezoelectric films such particles can be used for detecting load states.
Microscopic image of the focused double full bridge 2D GMR spin valve sensor in monolithic integration. The yellow arrows illustrate the locally set magnetization of the pinned layers.
Micromechanical wake-up receiver with bonded glass cover manufactured in airgap insulated microstructures (AIM) technology.
Polymer-based piezoelectric accelerometer fabricated by the novel polySENS technology.
Within the flagship project A “Nano scale material systems for magnetoresistive sensors”, headed by Prof. Stefan Schulz from Fraunhofer ENAS, the partners are working on novel magnetoresistive sensors on the base of the giant magnetoresistance effect (GMR). The aim is the development of monolithically integrated multi-axes spin valve structures for high precision and highly integrated magnetic field sensors. In comparison to commercial products, which are working mostly on the base of the AMR effect, the level of integration will be higher and the spatial resolution will be significantly increased.
For the lateral directions, two full Wheatstone bridges of the multilayer stack have to be designed and patterned by ion etching or fs-laser ablation. In that course the change of material properties, which are important for the sensor function, have to be avoided. The most challenging task is the local setting of the exchange bias perpendicular to the resistor stripes of a meander structure, and with opposite directions in adjacent meanders. This is done by laser treatment in close cooperation with the group of Prof. Exner at the University of Applied Sciences Mittweida.
In order to measure the out-of-plane direction (Z-axis) of a magnetic field multilayer systems with vertical anisotropy are investigated and optimized with respect to spin valve properties and suitable patterning processes. This structure would give the opportunity of fabricating monolithically integrated three-dimensional magnetic field sensors, which can be used for monitoring the absolute position of an object within a magnetic field.
The amount of miniaturized sensor nodes for monitoring applications is expected to reach huge numbers in a few years. Currently the application fields automation technology, condition monitoring of tools, machinery and buildings, the energy sector and safety systems are being investigated. Important issues for these nodes are the data rate and the energy consumption. For current systems the data rate is small but it will increase drastically in the future. This demands the usage of ultra-wideband communication techniques at the same time with efficient communication strategies because of the limited processing power and energy supply of miniaturized sensor nodes.
In the flagship project B “Integration of NEMS, MEMS and electronics for energy efficient sensor nodes”, which is headed by Dr. Steffen Kurth, the scientists are developing technologies for the next generation of sensor networks. Besides data compression, smart routing, radio frequency electronics, integration technologies and energy management, especially energy efficient wireless communication is in the focus of the scientists from Fraunhofer ENAS.
For ad-hoc asynchronous data transmitting the transceiver has to be permanently in the on state. Using a transceiver with a stand-by listening mode can overcome this problem. For this purpose a wake-up receiver (WuRx), has been developed in the nanett project. The WuRx has been realized by a passive MEMS RF mixer with integrated filter for permanently monitoring the radio channel and activating the transceiver if a signal is detected. Together with the Center for Microtechnologies and the Leibniz IHP the MEMS are monolithically integrated in one chip with the RF electronics in SiGe:C BiCMOS technology.
The use of lightweight structures in constructions, aircrafts or the automotive sector is an emerging field. Due to its typical failure mechanisms lightweight components should be monitored. Especially for fiber reinforced polymers structural health monitoring is an important issue. The aim of flagship project C “Material integrated sensors based on nano effects” is the development of a smart component which can detect and visualize temporary load states in an indicative polymer layer. The flagship project C is led by Prof. Thomas Otto.
The idea is to realize sensor functions within the polymer material instead of integrating discrete sensor systems. Therefore, sensor and actuator functions like piezoelectricity or fluorescence have to be integrated into the polymer material by using nanoparticles. Thus, the advantages of nano effects can be used by mass fabricated products.
A further system, which is developed within the nanett project, is detecting the load state by a piezoelectric layer, which is generating electrical charges. Since a permanent monitoring of the whole component is economically and technologically not reasonable, the storage of the load state is an important issue. The group of Dr. Jörg Martin at Fraunhofer ENAS is therefore developing a fluorescent layer by integrating quantum dots in the polymer matrix. The charges are guided to the quantum dots, being stored inside of the nano particle, and switching the fluorescence property off, as long as the charge is trapped.
For further information, please visit nanett.org