Integrated semiconductor fluorescent detection system for biochip and biomedical applications

As biological analysis systems scale to smaller dimensions, the realization of small and portable biosensors becomes increasingly important. We present the monolithic integration of vertical cavity surface emitting lasers, PIN photodetectors and optical emission filters to be used as a fluorescence sensor. The integration will drastically reduce cost and size of fluorescence detection systems. Also, parallel sensing architectures of more than one hundred channels will be possible. PIN heterostructure photodetectors have been fabricated and tested. Photodetector experiments show extremely low dark current of less than 500 fA/mm, quantum efficiency greater than 85 percent and linear detector response. Optical simulations have been preformed to evaluate the performance of a proximity sensing architecture. These simulations predict a detection sensitivity lower than 10000 fluorescent molecules in a detection area of 10⁴ μm²