Hydrogen sensor based on field effect transistor with C-Pd layer

Piotr Firek , Sławomir Krawczyk , Halina Wronka , Elżbieta Czerwosz , Jan Szmidt

Abstract

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.