Colour sensor for (bio)chemical/biological discrimination and detection

Life science is a field of dynamic development and can benefit from the usage of microelectronics in numerous applications. Various devices for separation of different (bio)chemical components from a mixture could be miniaturized in silicon, but they need detectors at their output to identify and characterize the separated elements. The colour sensor is such a detector, and it was preferred because other classical approaches typically used in chemistry or biology employ IR or UV-based analysis, for which it is more difficult to design, optimize and fabricate a silicon-based sensor. Unlike classical detection (using three different filters placed on separate detectors) the proposed device is based on an entirely different approach, using vertically stacked detectors within a single structure that can be fabricated using CMOS-compatible processing. The main requirements for the design of such a vertically stacked multi-junction structure are presented, together with details regarding the most critical processing steps and process parameter values obtained after simulation which were used in the manufacturing of the first version of the device, including some optical design aspects.