Four Electrode Bioimpedance Sensor System on CMOS Chip

In this work, we explore the implementation of an integrated complementary metal-oxide-semiconductor (CMOS) multi-electrode array (MEA) dedicated to 4-electrode bioimpedance measurements. The sensor consists of an 8 x 8 pixel array, where each pixel contains an inner circular current carrying (CC) electrode and an outer voltage pick up (PU) ring electrode. The CC electrode has a diameter of 10 mu m, and the PU electrode has an inner and outer diameter of 20.9 mu m and 29.3 mu m respectively. The pixels were defined by openings in the passivation layer exposing the aluminum top metal layer, which will be electroplated with gold in later work. The integrity of the pixel metal stack was confirmed by focused ion beam (FIB) scanning electron microscopy (SEM), and initial bench top testing with electrical probes was performed to validate the functionality of the on chip amplifiers and pixel addressing.

Automated summary

This study explores the implementation of an integrated CMOS multi-electrode array for bioimpedance measurements. The sensor consists of an 8 x 8 pixel array, where each pixel contains inner circular current carrying electrode and outer voltage pick up ring electrode. The integrity of the pixel metal stack was confirmed by FIB-SEM, and initial bench top testing was performed to validate the functionality of on chip amplifiers and pixel addressing.