In this work we combine a Fin Field Effect Transistor (Fin-FET) characterised by a high height to width aspect ratio with high-k dielectric materials to study the optimized design for chemical-FETs to provide higher transconductance (and thus a better signal to noise ratio), increased dynamic range and chemical stability. We used pH sensing to verify the design. We explored the sensitivity and linearity of the response of silicon dioxide, alumina and hafnium oxide as dielectric materials sensing pH, and compared their chemical stability in different acids. The high aspect ratio fin geometry of the sensor provides high currents, as well as a planar conduction channel more reliable than traditional silicon nanowires. The hafnium oxide Fin-FET configuration performed the best delivering the most linear response both for the output and transfer characteristics, providing a wider dynamic range. Hafnium oxide also showed the best chemical stability. Thus we believe that the developed high aspect ratio Fin-FETs/high-k dielectric system can offer the best compromise of performance of FET-based sensors.
- High-k dielectrics
- Electrochemical sensing