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 in 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.