Smart microplates: photodiode within silicon pyramidal cavity for detecting bead-based chemiluminescence and AC characterization for RFID-type readout

An improved photodiode integrated into a micromachined silicon pyramidal cavity, a part of an electronic taste chip, for the purpose of detecting bead-based chemiluminescent reactions is presented. In our earlier work [1], we demonstrated the fabrication of such a photodiode using ion implantation; unfortunately, a rather large dark current was observed. Additionally, we have introduced a concept of accessing a photodiode via an inductively coupled non-contact readout. The efforts discussed here emphasize key issues in the fabrication sequence that produce integrated photodiodes with significantly less dark current. We have also preformed AC characterization of the integrated photodiodes in order to allow the design of an optimized wireless, non-contact readout for detecting a chemiluminescent reaction.