A dual-gate (DG) ion sensitive field effect transistor (ISFET) using capacitance coupling effect has recently been proposed to overcome the Nernst limitation as 59 mV/pH. In this study, we focus on the analysis of sensing characteristics by various oxide capacitances and channel thickness using intensive measurement on conventional fully depleted (FD) silicon-on-insulator (SOI) based DG ISFET. The enlarged oxide capacitance and reductive channel thickness enhance the capacitive coupling effect and increase sensitivity of DG ISFET. And also, the thin channel thickness reduced the leakage current in the DG operation. These will be very promising techniques for high performance biosensor application. (C) 2014 Elsevier Ltd. All rights reserved.