Through-Plastic-Via Three-Dimensional Integration for Integrated Organic Field-Effect Transistor Bio-Chemical Sensor Chip

A through-plastic-via (TPV) three-dimensional (3D) integration approach is developed to integrate the organic field effect transistor (OFET) circuitry and the sensing/reference electrodes (SE/RE) for flexible bio-chemical sensor chips. Based on this approach, the SE can be fabricated using optimal processes on a different plastic substrate without concern of affecting the OFET part. Taking H ⁺ detection as a proof-of-concept, it is demonstrated that a weak ion response ( ~ 7 mV induced by 0.2 pH) is amplified by 10 times through an integrated OFET common source amplifier. With close integration of the OFET amplifier and the SE, external noise influence can also be suppressed, beneficial for improving signal-to-noise ratio and improving the detection limit.