ISFET is the acronym for Ion-Sensitive Field-Effect Transistor. It is a type of field-effect transistor (FET) that is specialized for measuring the concentration of ions in a solution. It serves as a sensing element in ion-sensitive sensors and is commonly used in various fields, such as biomedical and environmental monitoring, as well as chemical analysis.
The ISFET works based on the principle of changes in the electrical conductivity of the transistor channel due to the presence of specific ions. Unlike traditional pH sensors that use glass electrodes, ISFET sensors utilize a thin insulating layer, typically silicon dioxide, as the gate oxide. This oxide layer is modified with a specific ion-selective material that allows it to respond selectively to certain ions in the solution.
When the target ions interact with the gate oxide, they cause a change in the surface charge, which in turn alters the electrical characteristics of the transistor channel. This change is then measured as a voltage or current output by the ISFET circuitry, providing information about the ion concentration in the solution.
ISFETs offer several advantages over traditional ion sensors, including miniaturization, higher sensitivity, faster response times, and compatibility with integrated circuit fabrication processes. They are also known for their versatility, as different ion-specific sensing materials can be applied to tailor them for various ion measurements.
In summary, ISFET is an ion-sensitive field-effect transistor that serves as a sensing element for measuring ion concentration in solutions. It offers numerous advantages and finds application in various industries for ion sensing and monitoring purposes.
