Highlights of the research by the professor of Biomedical Electronics and Bioinformatics Institute. -202203 Professor Lin, Chih-Ting

As a sensor, an ion-sensitive field-effect transistor (ISFET) can transduce the environmental information into electrical signals. So it have been applied in DNA sequencing, biomarker detection and pH sensing. Furthermore, ISFET is based on MOSFET device structure thus, it can be manufactured using a CMOS process.

According to the solution pH value, protons can associate or dissociate on the dielectric surface. This causes a charge variation at the solid-liquid interface, which in turn establishes a surface potential variation. This potential variation can affect the transistor current behavior. Therefore, the analyte pH value can be deduced based on the electrical signal variation.

However, CMOS-based ISFETs are still suffering problems of scaling attenuation. To deal with this, team of Pro. Lin developed a novel CMOS ISFET configuration, namely, 3D-T-ISFET. Based on their experiments, on the same footprint, a 3.21-fold ID/pH improvement can be achieved by developed 3D-T-ISFET, and it exhibits a scaling attenuation-free behavior! In addition, Pro. Lin designed another kind of configuration, which called “3D-extended structure”. This device exploits vertical space and more sensing surface area can be obtained in a given footprint area. In the end, 3D-extended structure improves pH sensitivity 1.5-fold in current mode and 1.15-fold in voltage mode.

The improvement of ISFET can enhance the accurate of CMOS device and shrink the detector. The pixels of the CMOS detector will be more meticulous too.



[1]        N. Y. Teng and C. T. Lin, “CMOS ISFETs With 3D-Truncated Sensing Structure Resistant to Scaling Attenuation and Trapped Charge-Induced Offset,” IEEE Sensors Journal, vol. 21, no. 24, pp. 27282-27289, 2021, doi: 10.1109/JSEN.2021.3126210.

[2]        N. Y. Teng, Y. T. Wu, R. X. Wang, and C. T. Lin, “Sensing Characteristic Enhancement of CMOS-Based ISFETs With Three-Dimensional Extended- Gate Architecture,” IEEE Sensors Journal, vol. 21, no. 7, pp. 8831-8838, 2021, doi: 10.1109/JSEN.2021.3052772.



ISFETs(Ion-sensitive field-effect transistors,離子敏感場效電晶體)是用於測量溶液當中離子濃度的電晶體,由於其結構相近於MOSFET(金氧半場效電晶體)故可以大量生產在COMS(互補式MOSFET)上以用來作為生物傳感器。在生物醫學的應用之中,ISFET常用來檢測DNA雜交檢測,血液中生物標誌物檢測,抗體檢測,葡萄糖測量和 pH傳感等。