Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications

146 Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications

© 2011 by Taylor & Francis Group, LLC

to a current variation ratio of 4.12%. The resolution of an ultrathin InN-based ISFET can be further

improved to less than 0.05 pH using the AC-mode measurement at 1 kHz. For polarity sensing, the

current variation of ISFETs shows a linear relationship to the value of p/ε of the polar liquid, which

is attributed to the potential drop at the liquid–solid interface due to the molecular dipole of the polar

liquid. In comparison with the conventional ISFET using an open-gate Si-based FET, the InN-based

ISFET possesses the advantages of simple structure, easy fabrication, and the potential of integration

with the read-out circui ...