Development of a High Sensitivity, Wide Range CMOS Capacitive DNA Sensor Array

The charge carried by biomolecules immobilized on the electrode surface causes a direct change in the electrode capacitance, enabling capacitive sensors to provide label-free real-time detection for point-of-care diagnostic applications. This work presents a 16 × 16 capacitive sensor array implemented in a 0.35-μm complementary metal oxide semiconductor (CMOS) process. The signal-to-noise ratio of on-chip switched-capacitor readout benefits from the reduced parasitic capacitance through monolithic integration. The interdigitated sensing electrodes have an area of 30 × 30 μm ² and a measured capacitance of 57.3 fF in air. The pH measurement exhibited a capacitive sensitivity of 151 fF/pH. The deoxyribonucleic acid (DNA) measurements showed a capacitive sensitivity of 94 fF/log 10 [DNA] from 10 aM to 100 pM.