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Fraunhofer-Institut for Integrated Circuits
Company Description
The Fraunhofer Gesellschaft is the leading organization for applied research in Europe, undertaking contract research on behalf of industry. Its Institute for Integrated Circuits (IIS) has been designing integrated circuits in silicon CMOS technologies for manufacturing via cooperation partners. Fraunhofer IIS has been working on colour and polarization sensors using plasmonic effects and the small structure sizes of CMOS technology in the subwavelength range for fabrication in high volume.
Contact Information
Am Wolfsmantel 33
Erlangen
Germany
Press Releases
| Nanostructured Color and Polarization Sensors for Mass Fabri
Since about 10 years many efforts in basic research have been focussing on the utilization of plasmonic effects on metal films for sensing or other applications. The results were impressive, but so far the fabrication methods for the required subwavelength structures were limited to laboratory use.
At the Fraunhofer Institute for Integrated Circuits IIS in Erlangen, Germany, for the first time an efficient implementation of subwavelength structures in a CMOS process hass been shown, that is ready for mass production. Not only plasmonic effects in aluminium are being used there, but also structuring of dielectric layers. Thus, tailored color and polarization sensors are being implemented that show spectral filter performances with bandwidths of 20 nm to 100 nm in the visible wavelength range and with a transmission of 20% to 60%. For realization of polarization sensors the transmission is even higher and reaches up to 85%. These are the best performances ever achieved so far for these types of sensors and those results now allow for real practical use of this technology.
With these new types of filters and sensors, almost arbitray, tailored filter and sensor performance can be implemented in a CMOS technology just by appropriate design of the relevant metal and/or dielectric layers. This requires in a first step the adaptation of the relevant layers in the CMOS process and the definition of dedicated „optical layers“ that shall not be used for electrical functions. But once these dedicated layers have been defined and implemented in CMOS, they can be used for designing tailored filter performances without further process modification or adaptation. This means, that no additional filter layers etc. have to processed on top of a CMOS chip but the processing of the optical layers is already part of the process.
This achievement has been reached by close cooperation of the Fraunhofer IIS with two medium-sized, but globally operating CMOS foundries, XFAB and LFoundry. Both foundries are pursuing the strategy of „More than Moore“ and are going to implement advanced functionalities in their CMOS processes in addition to the pure electrical performance.
The applications of the new types of sensors are manifold. Tailored sensor functions can be implemented on the same chip and with a small sensor size down to pixel level. Thus, micro-spectrometers, multi-spectral imaging sensors, and polarization image sensors and cameras can be built – and all this at the price of mass-fabricated, low-cost CMOS technology. One can think of nonreturnable, real cheap monitoring devices in medical applications or of low-cost spectroscopic monitoring of chemical or combustion processes both in household applicances and industry. Project partners of the Fraunhofer IIS are already working on a polarimeter for measuring sugar concentrations in bio reactors and on color sensors for large printing machines, where 7 colors have to be monitored – and currently are not due to a lack of appropriate sensors. Further ongoing developments are targeting a polarization camera that can be used e.g. for ice and water detection or for detection of mechanical stress in transparent materials like glass or polymers. Furthermore, the first spectroscopic applications are being discussed with customers. |
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