C1.4 - Characterization of Si Mid-infrared Photonic Components for Chemical and Gas Sensing

AMA Conferences 2015
2015-05-19 - 2015-05-21
Nürnberg, Germany
Proceedings SENSOR 2015
C1- MEMS Applications
U. Hedenig, T. Grille - Infineon Technologies Austria AG, Villach (Austria), G. Ritchie, J. Kirkbride - University of Oxford (UK), B. Jakoby, V. Lavchiev - Johannes Kepler University, Linz (Austria)
356 - 360


The paper discusses how, using proper design and modelling, IR-absorption sensors could achieve appropriate detection sensitivity, with micron- and submicron dimensions and to be integrated within asingle-platform device. Detailed material and structure characterization along with the employed technology is demonstrated for the recently fabricated prototypes. In our device concept, a MIR source emits electromagnetic (EM) field, coupled with a Si waveguide (WG). The latter operates as an interaction volume leading to partial absorption of energy in the sample yielding an attenuation of the guided wave. It is detected at the output with a MIR detector. By careful choice of the waveguide thickness, it is possible to change the detector’s sensitivity. There is an interaction of the thickness and the absorption by coated fluid. In case of a rib WG or the characteristic geometry dimensions in a photonic crystal (PhC) WG the desired spectral range of operation can be obtained by proper tuning
the waveguide width and height. To evaluate the device performance, photonic simulations with the finite difference time domain (FDTD) method and beam propagation method (BPM) in 3D are applied. These are powerful methods, which verified the guiding EM modes, the attenuation of the field along the WG and resulted in optimization of the device dimensions. The developed Si photonic components, are suitable for integration into a miniaturized sensor system and operates in the wavelength region λ=3-7 μm. This sensor configuration is compatible to the Si technology and can also be realized on a single chip. In addition, the principle of operation is not limited to a single wavelength. It can be applied to a broad spectral range too.