Holst Research Centre in the Netherlands, now run by IMEC, has achieved an enviable record in energy harvesting development in only three years. Here are a few aspects:
Vibrational energy harvesting
Both piezoelectric and electrostatic energy harvesters are developed using micromachining with complete MEMS microgenerators a focus and at least 100 microwatts/cm2 an objective. Both PZT and AlN materials are used and two concepts of electrostatic generator are being explored. Electrostatic, otherwise known as capacitive harvesting becomes attractive at micro scale where the most attractive bulk forms of harvesting - photovoltaics and electrodynamics, cease to be scalable. Already a world record for power output has been achieved.
Record power output from vibrational energy harvester
A new record was achieved for micromachined piezoelectric energy harvesters, now delivering an output power of 60µW/cm2. The harvester can be realised with a simple, low-cost CMOS-compatible production process by using aluminium nitride (AIN) as piezoelectric material. The low resonance frequency of only 500 HZ makes the device widely applicable. The outpower of 60µW/cm2 is sufficient to drive simple wireless sensors that intermittently transfer sensor readings to a master. Potential applications include tire pressure monitoring systems (TPMS) or monitoring of industrial equipment.
The approach is comprehensive, with the Holst Centre also working on ultra low power radio and other complementary projects.
Recently, Holst Centre and MiPlaza officially presented a newly installed atomic-layer deposition (ALD) tool that will support the activities on ultra-low power sensors and other MEMS applications. It is the centerpiece of a joint development project that can open new application domains for ALD.
In CMOS processing, atomic layer deposition (ALD) is a proven technique for depositing ultra-thin layers of for example insulating high-k gate materials. Also in other domains, such as the production of hard disks and storage media, ALD is already used. For the domain of MEMS processing however, examples of deploying ALD are virtually non-existent.
At Holst Centre, an open-innovation initiative by IMEC and TNO, the opportunities will be investigated for ALD to contribute to the research programs on Micropower Generation and Storage and on Ultra-Low Power Sensors and Actuators. As one example, ALD might be a candidate to deposit thin functional layers determining the sensitivity of a sensor for a gas or other compound. While this is the initial focus of Holst Centre research with the tool, programs in the Systems-in-Foil domain are also being assessed.
For ASM, already a member of the IMEC Leuven partner network for several years, involvement in the research at Holst Centre holds promise of opening new markets. The outcome of research conducted with the ALD tool will allow the leading semiconductor equipment vendor to get insight in the requirements of these new application fields of MEMS and ultra-low power sensor applications.
MiPlaza, part of Philips Research, is involved in two ways. First, it provides the clean room facilities where the tool is located. Second, MiPlaza will bring this new capability to the attention of its existing clients and partners for possible use in their research programs, enabling the ALD tool capacity to be optimally utilized. Moreover, it brings a complementary area of expertise to MiPlaza's service portfolio in the domain of nanotechnology. MiPlaza and Holst Centre are close neighbors on High Tech Campus Eindhoven, a setting that stimulates joint collaboration and partnership.
By sharing high-tech expertise, equipment and infrastructure, the entire project illustrates how joint collaboration can generate fruitful outcomes. Such collaboration is particularly relevant in these times of economic crisis, showing that combining forces can yield mutual benefit for the wider research community.
For more see www.holstcentre.com 
For more attend: Energy Harvesting & Storage USA 2009
