ISFETs with sputtered sodium alumino-silicate glass membranes

Area of Science:

• Materials Science
• Electrochemistry
• Sensor Technology

Background:

• Sodium ion sensing is crucial for various applications.
• Existing sodium ion selective electrodes have limitations.
• Development of novel materials for ion-sensitive field-effect transistors (ISFETs) is needed.

Purpose of the Study:

• To investigate sodium aluminosilicate (NAS) glass membranes for ISFET applications.
• To evaluate the performance characteristics of NAS-based ISFETs for sodium ion detection.
• To compare the sensor properties with commercial sodium ion selective electrodes.

Main Methods:

• Fabrication of NAS glass membranes using reactive sputtering.
• Characterization of NAS film composition and properties.
• Evaluation of ISFET performance including sensitivity, selectivity, response time, drift, and lifetime.

Main Results:

• NAS films with reproducible composition were obtained.
• Annealing at 450°C minimized radiation damage in the gate dielectric.
• ISFETs demonstrated near-Nernstian Na(+) response down to 10(-4) mol/l at pH ≥ 7.
• NAS membranes exhibited physical robustness and excellent chemical durability, with sensors lasting ~8 months.
• Sensor performance was comparable to commercial Na(+) selective glass electrodes.

Conclusions:

• Reactively sputtered NAS glass membranes are suitable for fabricating high-performance sodium ion sensitive field-effect transistors.
• NAS-based ISFETs offer a promising alternative to conventional sodium ion sensors due to their durability and comparable performance.
• The developed NAS-based ISFETs show potential for reliable and long-term sodium ion monitoring.