A novel functionalization of AlGaN/GaN-ISFETs for DNA-sensors


AlGaN/GaN pH sensitive devices were functionalized and passivated for the use as selective bio-sensors. For the passivation, a multilayer of SiO2 and SiNx is proposed, which stabilizes the pH-sensor, is biocompatible and has no negative impact on the following biofunctionalization. The functionalization of the GaN-surface was achieved by covalent bonding of 10-amino-dec-1-ene molecules by a photochemical process. After two different surface preparations islands of TFAAD are growing on the sensor surface by exposure with UV-light. In dependence on the surface pre-treatment and the illumination wavelength the first monolayer is completed after 3 h or 7 h exposure time dependent on the pre-treatment and illumination wavelength. Further exposure results in thicker films as a consequence of cross polymerization. The bonding to the sensor surface was analyzed by X-ray photoelectron spectroscopy, while the thickness of the functionalization was determined by atomic force microscopy scratching experiments. These functionalized devices based on the pH-sensitive AlGaN/GaN ISFET will establish a new family of adaptive, selective biomolecular sensors such as selective, reusable DNA sensors.

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The authors would like to acknowledge the assistance of Nadine Geldmacher, Gudrun Kaufel, Mechthild Korobka, Brigitte Wieber, Arnulf Leuther and Brian Raynor. This work was supported by the Fraunhofer Attract program and the Fraunhofer “Doktorandinnenprogramm: Mehr Frauen in die angewandte Forschung”. The authors also would like to thank the help of the ZMN in Ilmenau which is supported by the BMBF Optimi.

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Linkohr, S., Schwarz, S.U., Krischok, S. et al. A novel functionalization of AlGaN/GaN-ISFETs for DNA-sensors. MRS Online Proceedings Library 1202, 62 (2009). https://doi.org/10.1557/PROC-1202-I06-02

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