Fabrication of high-performance dual-gate ISFET pH sensors using In2O3 nano-channel

Abstract

Here, a high-performance dual-gate ionsensitive field-effect transistor (ISFET) was designed for pH detection based on the high carrier mobility and chemical stability of In2O3. To optimize the structural parameters of the ISFET, the ISFET model with a dual-gate structure was constructed using the Silvaco TCAD. The effects of the channel layer and gate dielectric layer parameters on the performance of the ISFET model were investigated in the dual-gate structure. Following the optimal parameters of the simulation, the dual-gate ISFET chip was fabricated by microfabrication techniques. The pH sensitivity of the fabricated chip was 321.54 mV/pH and exhibited good stability with low drift and hysteresis voltage. In addition, we also tested the pH change caused by the hydrogen peroxide oxidation reaction under catalysis by horseradish peroxidase. The sensitivity was up to 103.28 µA/mM, verifying this high-performance ISFET can be used to detect pH changes of trace substances in the biosensing field.