Ion sensitive field effect transistor (ISFET)

The ion sensitive field effect transistor (ISFET) is an instrument in surface technology, particularly in areas such as biosensors and analytics. Unlike conventional field-effect transistors, which mainly amplify electrical signals, the ISFET is sensitive to changes in the concentration of ions in its environment.

The ISFET consists of a semiconductor material such as silicon, to which an insulating layer and a sensitive gate electrode are applied. The insulating layer serves as a dielectric, while the gate electrode contains specific materials that can react selectively to certain ions. When ions are bound to the surface of the ISFET, they change the electrical properties of the semiconductor and thus the conductivity of the transistor.

In surface technology, the ISFET is often used as a sensor to measure ion concentrations in liquids or gases. This makes the ISFET a valuable tool in applications such as pH measurement, ion detection and chemical analysis. By combining the ISFET with specific ion-sensitive materials, high-precision sensors can be developed that can react sensitively to certain types of ions.

The use of ISFETs in surface technology offers a number of advantages, including high sensitivity, fast response times and the ability to collect data in real time. In addition, ISFETs can be manufactured in miniature format, which facilitates their integration into complex systems and applications. Overall, the ion-sensitive field effect transistor is a powerful tool in surface technology, enabling precise and reliable measurement of ion concentrations and supporting a wide range of applications in the fields of biosensing, analytics and medical technology.