A novel extended gate ISFET design for biosensing application compatible with standard CMOS

This paper describes a novel design of ISFET, which uses a hafnium oxide-coated aluminum pad surface as a floating/extended gate. The design was realized using standard CMOS technology followed by BEOL post treatment. The ISFET was designed to operate in subthreshold mode and has subthreshold slope of 108 mV/dec, pH sensitivity of 55 mV/pH and temporal stability 0.008 mV/min. Based on the ISFET, an enzymatic biosensor for detection of phenols in real samples was demonstrated. The reported design allows to significantly improve the internal characteristics of ISFET, leading to predictable high-performance biosensors formed on a basis of standard CMOS-technology.