A CMOS Image Sensor Integrated with Plasmonic Colour Filters

• Published in: Plasmonics (Norwell, Mass.) Mass.), 2012-12, Vol.7 (4), p.695-699
• Main Authors: Chen, Q., Das, D., Chitnis, D., Walls, K., Drysdale, T. D., Collins, S., Cumming, D. R. S.
• Format: Article
• Language: English
• Subjects: Biochemistry; Biological and Medical Physics; Biophysics; Biotechnology; Chemistry; Chemistry and Materials Science; Nanotechnology
• ISSN: 1557-1955; 1557-1963
• DOI: 10.1007/s11468-012-9360-6

Multi-pixel, 4.5 × 9 μm, plasmonic colour filters, consisting of periodic subwavelength holes in an aluminium film, were directly integrated on the top surface of a complementary metal oxide semiconductor (CMOS) image sensor (CIS) using electron beam lithography and dry etch. The 100 × 100-pixel plasmonic CIS showed full colour sensitivities across the visible range determined by a photocurrent measurement. The filters were fabricated in a simple process utilising a single lithography step. This is to be compared with the traditional multi-step processing when using dye-doped polymers. The intrinsic compatibility of these plasmonic components with a standard CMOS process allows them to be manufactured in a metal layer close to the photodiodes. The incorporation of such plasmonic components may in the future enable the development of advanced CIS with low cost, low cross-talk and increased functionality.