Novel all-silicon sensor structure with integrated poly-Si electrodes

The interest in miniaturization of modern chemical and medical sensors is steadily increasing. However, when employing methods and fabrication procedures especially developed for microelectronics, one may encounter new and unpredictable problems for applications in aqueous media. For instance, in microelectronics often a dual metal layer system is employed for making electrical contacts. In a solution such a contact may result in galvanic reactions and/or may dissolve in the cleaning agents used for sterilization of medical devices. To address such issues we have employed an all-silicon based process technology for fabrication of sturdy and reliable devices with integrated poly-Silicon electrodes that tolerate most chemical environments. In this presentation we will report on the first results using such electrodes. A comparative study between identical poly-Si and Aluminium electrodes was made in order to investigate the usefulness of poly-Si electrodes. We will also demonstrate the nice possibility to use wall-documented methods for surface modifications using silane coupling chemistry. We believe this added benefit for the silicon based electrodes of easy surface modification processes, as compared with metal electrodes, to be extremely valuable for the development of accurate and tailored sensor structures for specific applications.