Investigation of CMOS BDJ detector for fluorescence detection in microarray analysis

For applying the CMOS BDJ (Buried Double p-n Junction) detector to fluorescence detection in microarray analysis, we have designed and tested the device integrated on a test chip. The main characteristics of the fabricated detector have been measured. The testing of fluorescence detection using the device has also been performed. It has been verified that, depending on the use of an output current or a photocurrent ratio as the detector response, the device can detect either fluorescence intensity or spectral variations. The output current is proportional to the received incident flux, while the photocurrent ratio is sensitive to color changes. This two-fold operation eliminate the need to combine optical wavelength-selective devices for fluorescence detection in many biomedical applications. In addition, the device implementation using simply a CMOS process offers important advantages for on-chip system integration. The use of the CMOS BDJ detector may provide an alternative way to implement fluorescence detection in developing microarray analysis systems.