Bio-inspired pH sensing using ion sensitive field effect transistors

• Published in: 2016 IEEE International Symposium on Circuits and Systems (ISCAS) pp. 2835 - 2838
• Main Authors: Lallement, Guenole, Moser, Nicolas, Georgiou, Pantelis
• Format: Conference Proceeding Journal Article
• Language: English
• Published: IEEE 01.05.2016
• Subjects: Attenuation; Capacitance; CMOS; Devices; Gates; Logic gates; Noise; Semiconductor devices; Sensors; Silicon; Transistors
• ISSN: 2379-447X
• DOI: 10.1109/ISCAS.2016.7539183

In this paper, we present a novel bio-inspired CMOS-based hexagonal ISFET sensor which, compared to traditional devices, exhibit a more compact arrangement as part of large arrays and provides benefits in terms of capacitive attenuation. We classify these novel sensors as Enclosed Gate Transistors (EGTs) and provide a layout in standard AMS 0.35 μm technology. Electrical characteristics are derived theoretically for the device, including an effective W/L, and simulations for both AMS 0.18 and 0.35 μm CMOS processes are provided. The results indicate a decrease in parasitic gate capacitance between 20 % and 40%, highlighting the advantages in attenuation of respectively 0.36 dB and 0.71 dB for the smallest lengths of devices. The noise performance is also improved, with the input referred noise reduced by 1 or 2 % for each process. The devices were fabricated in standard 0.35 μm CMOS technology for future characterisation.