Single Si3N4 layer on dual substrate for pH sensing micro sensor

In this study, a novel approach for realization of an inorganic ISFET/REFET system was presented. Single Si
₃
N
₄
layer was used as the sensing membrane of EIS structure directly on n and p type substrate. The differential pH sensitivity of them is 25.1 mV/pH, and the linearity is higher than 99%. The drift effect for the single Si
₃
N
₄
EIS structures could be minimized to around 1 mV/h by this differential arrangement. Besides, light and hysteresis effect for both conditions were investigated.