Integrated Angle-Insensitive Nanoplasmonic Filters for Ultraminiaturized Fluorescence Microarray in a 65 nm Digital CMOS Process

In this work, we demonstrate for the first time massively parallelizable nanoplasmonic structures and integration of electronics in the same substrate in CMOS. We adopt the same “fabless” approach in today’s semiconductor industry with absolutely “no change” of either fabrication or processing and show that copper interconnects in an industry standard digital CMOS process (65 nm node) can be exploited to allow subwavelength optical field processing in a massively scalable fashion. We demonstrate this in the context of eliminating all external optics and enabling the first optics-free fully integrated CMOS fluorescence-based biosensor array. The system has massively multiplexed biomolecular sensing capability for DNAs with surface sensitivity comparable to commercial fluorescence readers. The angle and scattering insensitive nature of the filter, relying on coupled surface-plasmon polariton modes, allows us to eliminate all external optics and miniaturize the entire 96-sensor array system (including a LED source) within 0.1 cc of volume. The system demonstrates detection sensitivity of less than 1 molecule/μm2 or zepto moles of quantum dot based fluorophores on the chip surface. The electronic–nanophotonic codesign approach allows us to optimally partition optical and electronic filtering, enabling us to detect fluorescence signal 77 dB lower than the excitation. Such CMOS-based nano-optical systems can lead to novel chip-scale optical sensors for in vitro and in vivo applications.