Inline relative permittivity sensing using silicon electrodes realized in surface channel technology

Abstract

Sensing relative permittivity is useful for fluid characterization, since its value differs significantly for different substances. A microfabricated inline relative permittivity sensor is realized using surface channel technology with support for isolated silicon electrodes. This enables non-invasive composition measurements of chemicals, i.e. the chemicals are not in contact with an electrode, do not need to be heated or need to be mixed with a chemical marker. Since this sensor operates inline, real-time measurements of the fluid can be obtained. Besides, integration with other fluid sensors, e.g. flow or pressure sensors, on a single chip could be achieved due to the sensor's full compatibility with surface channel technology. This is the first device that successfully uses the isolated silicon electrode functionality of this fabrication technology. Preliminary measurement results show a high coefficient of determination (R2 = 99.83 %) with the model.