Optical Nanostructures in CMOS Technology

Optical nanostructures in CMOS technology

Schematische Zeichnung des Substrats, Photodioden und plasmonische Filter-Struktur der nanoSPECTRAL-Technologie.
© Fraunhofer IIS / Wladimir Tschekalinskij
Schematic drawing of the substrate, photodiodes and plasmonic filter structure

With our nanoSPECTRAL technology, complex colour, spectral and polarization sensors are produced cost-effectively, which record the spectral properties and polarization state of the incident light. This opens up new possibilities for the spectral analysis of light sources and objects in transmission and reflection. The basis for this are photodiodes and optical nanostructures that are integrated into metal layers of CMOS processes. This means that the metal layers used in a modern semiconductor process are structured in the nanometer range and thus filters, photodiodes and analog and digital signal processing are integrated. This results in highly integrated, monolithic sensors with many spectral channels at low cost. In contrast to conventional optical filters such as thin-film filters, our optical nanostructures do not require any additional steps such as the application of optical filter layers. Since the nanoSPECTRAL technology is available in a commercial CMOS process, products based on it are available in industrial quality and at short notice.

At a glance: Technical keyfacts and benefits

Keyfacts Benefits
  • Realization of many multispectral channels on one chip with direct fabrication in the CMOS semiconductor process
  • Optical nanostructures in thin metal layers
  • Design of specific spectral behaviors
  • Can also be applied to existing single or image sensors
  • Integrated signal processing and standard interface such as SPI
  • Single-source production
  • Consistently low process costs with almost any number of spectral channels
  • High temperature resistance
  • Application-specific filter properties
  • Easy implementation in standard products
  • Independent service design and supply chains
  • Fast series transfer

Our offer: Cost-effective realization of many spectral channels

We have an in-depth understanding of the surface plasmon effects on CMOS-relevant materials and use our expertise in optics to develop filters. This expertise in optical nanostructures in CMOS technology enables us to offer you solutions along the entire development process and meet the requirements of your specific applications:

  • Simulation of optical nanostructures with spectral filter effect and with effect as polarization filters
  • Design of photodiode arrays and image sensors
  • Production run of integrated sensors
  • Electrical and optical characterization
  • System design for numerous applications

Applications: New horizons in spectral analysis

Depending on the application, it is possible to adjust the number of spectral channels, photodiodes and pixels, vary the wavelength of the channels and design the geometry according to the customer's specific requirements. This flexibility, together with the cost-efficient manufacturing method of our nanoSPECTRAL spectral sensor solution, opens up a wide range of new, price-sensitive application possibilities:

  • Smart farming in agriculture
  • Analysis of gases by measuring color changes
  • Analysis of liquids by spectral absorption measurement
  • Food analysis by measuring reflectance spectra
  • Medical applications at the point of care
  • Color control for LED lighting systems
  • Analysis of moisture, ingredients and irritants in hygiene products
  • Applications in cosmetics

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The aim of the project is to determine the condition of plants in the field and to reduce the amount of weed-killing agents such as herbicides through targeted use. We are involved in the project with the design and simulation of the spectral properties of the filters and the chip design of the sensor IC as well as the optical characterization of the implemented multispectral sensors.


Fraunhofer IIS Magazine

nanoSPECTRAL for agricultural and analytical applications

How is it possible to produce spectral sensors cost-effectively? Watch the video to see how sensor manufacturers for agricultural applications and environmental, food or water analysis can benefit from nanoSPECTRAL technology.


Services offered

Optical sensors and image sensors