Simulation and experimental study of the pH-sensing property for AlN thin films

The aluminum nitride (AlN) thin film has been investigated for using in pH-ISFET (ion-sensitive field-effect transistor) devices. The AlN thin film was used as the sensitive membrane for simulating and analyzing the pH sensing properties. According to the simulation, we find that the AlN/SiO2 gate ISFET has high pH sensitivity and has a linear response for the current-voltage (I-V) and capacitance-voltage (C-V) curves. In the simulation, the pH sensitivity is about 52-59.8 mV/pH for adapting ill all testing solutions (pH = 1-14). In addition, in the experiment, the I-V and C-V curves of AlN/SiO2 gate ISFET were also measured and the pH-sensing property was discussed in the different buffer solutions.