Realization of CMOS-Based Multimodal Image Sensor for Three-Dimensional Force and PH Measurement

We realized a CMOS-based multimodal image sensor for measuring three-dimensional force and pH for the first time. Using semiconductor photolithography, the force-sensitive region, which consisting of a piezoelectric film and a MEMS microstructure array (A single-element; $8\times 8\ \mu \mathrm{m}$), and the pH-sensitive region were constructed on a $2\ \mu \mathrm{m}-\text{pitch}$ CMOS potentiometric array sensor. Based on visualization experiments to detect force and pH response, the clear output image was observed due to force change on a single microstructure and pH change in a solution, demonstrating multimodal sensing on the fabricated sensor.