2014/08/25 by Da Zhang, Xindong Gao, Si Chen +5 · 1 citation
Chemical Engineering · Chemistry · Engineering · #Analytical Chemistry and Sensors #Electrochemical Analysis and Applications #Gas Sensing Nanomaterials and Sensors
paper · pdf · doi:10.1063/1.4894240
openalex publication_date 2014/08/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
This work presents a proof-of-concept ion-sensitive device operating in electrolytes. The device, i.e., an ion-gated bipolar amplifier (IGBA), consists of a modified ion-sensitive field-effect transistor (ISFET) intimately integrated with a vertical bipolar junction transistor for immediate current amplification without introducing additional noise. With the current non-optimized design, the IGBA is already characterized by a 70-fold internal amplification of the ISFET output signal. This signal amplification is retained when the IGBA is used for monitoring pH variations. The tight integration significantly suppresses the interference of the IGBA signal by external noise, which leads to an improvement in signal-to-noise performance compared to its ISFET reference. The IGBA concept is especially suitable for biochips with millions of electric sensors that are connected to peripheral readout circuitry via extensive metallization which may in turn invite external interferences leading to contamination of the signal before it reaches the first external amplification stage.