CMOS
3rd Generation BioSA Capacitive Sensor
Our third-generation platform advanced the second-generation design by scaling the sensing architecture to a 16×16 array of interdigitated electrodes and upgrading the interface electronics to a voltage-controlled oscillator (VCO)-based readout to improve measurement resolution. The system was fabricated in a 350 nm AMS CMOS process and validated across a range of applications, including oral cell monitoring, alcohol detection/monitoring, DNA mass measurement, and a time-of-evaporation sensing approach enabled by capacitive readout. The accompanying figure presents two device configurations: a simplified two-electrode sensor and the full 16×16 array. It also illustrates representative measurement results obtained using different concentrations (0–100%) of two alcohol types (Methanol (M), Ethanol (E)) and water (W) under multiple temperature conditions.
2nd Generation BioSA Capacitive Sensor
Building on our first-generation design, we expanded the sensing architecture to an 8×8 array of interdigitated electrodes and enhanced the interface electronics using a fully differential readout to improve sensitivity. The system was implemented in a 180 nm CMOS process and deployed for applications including cellular growth monitoring and drug testing, as illustrated in our demonstrations.
1st Generation BioSA Capacitive Sensor
Professor Ghafar-Zadeh developed a charge-based capacitive sensor using novel differential, current-mode interface circuitry to measure capacitance changes from interdigitated microelectrodes fabricated in a 180 nm CMOS process. In a subsequent iteration, we integrated a sigma–delta analog-to-digital converter (ADC) to enable high- resolution readout and evaluated the system across multiple applications, including chemical solvent monitoring, bacterial growth monitoring, and polyelectrolyte detection, as reported in our related publications.