ISFET (Ion Sensitive Field Effect Transistors) microsensors are widely used for pH measurements as well as analytical and biomedical applications. At the same time, ISFET is a good candidate for testing various materials for their applications in sensitive membranes. For example, hydrogen sensitive carbonaceous films containing Pd nanocrystallites (C–Pd) make this material very interesting for sensor applications. A cost effective silicon technology was selected to fabricate n-channel transistors. The structures were coupled to specially designed double-sided PCB (Printed Circuit Board) holder. The holder enables assembly of the structure as part of an automatic stand. The last step of production of MIS structures was deposition of the C–Pd layer. The C–Pd films were fabricated by the Physical Vapor Deposition (PVD) method in which C60 and palladium acetate were evaporated. Electrical resistance of structures with C–Pd films was measured during their interaction with hydrogen. Finally, a new type of highly sensitive FET hydrogen sensor with C–Pd layer was demonstrated and characterized.

The method of cleaning the ISFET structures after application of a biological substance was developed. There are few references in the literature to cleaning methods of this type of structure for biological applications, but they are relatively complex and difficult to automate. We decided to use resources commonly available in technological laboratories and methods that could be relatively easily automated, which would enable the full potential of ISFET transistors to be used. During the experiments, both acetone and deionized water were tested. The cleaning method was modified and it was checked whether it is possible to use such a method on one transistor more than once and how it affects the transistor's detection capabilities. We managed to obtain an effective method of cleaning ISFETs from biological substances. This method does not allow for obtaining exactly the same state as the original state of the transistor, but it ensures its correct operation and determining the influence of the tested biological substance on the transistor based on the results.