We fabricated the Si3N4 film-coated anodic aluminum oxide (AAO) template for chemical sensors. The average depth and diameter of pores were increased with increasing the second anodizing time and pore widening time, respectively. The average depth of pores of AAO template with the second anodizing time of 10 min was about 1.49 μm. The porous AAO sensor with the second anodizing time of 10 min and pore widening time of 15 min showed the highest capacitance of 142.92 nF. The capacitance increased in the pore widening time from 0 min to 10 min and gradually saturated at 15 min or more. The porous AAO sensor with the second anodizing time of 10 min and pore widening time of 10 min showed the good normalized C-V properties, and the pH sensitivity and the set values of the capacitance, working point, of these devices were 0.63 V, 0.27 V, 53.6 mV/pH and 48.2 mV/pH, respectively.

Keywords: Anodic Aluminum Oxide, Capacitive EIS, Biosensor.