Modeling of pH Dependent Electrochemical Noise in Ion Sensitive Field Effect Transistors ISFET

pH Ion Sensitive Field Effect Transistors (ISFET) are very important sensor for in vivo continuous monitoring application of physiological and environmental system. The accuracy of ISFET output measurement is greatly affected by the presences of noise, drift and slow response of the device. In this paper, the authors have investigated the low frequency pH dependent electrochemical noise that originates from the ionic conductance of the electrode-electrolyte-Field Effect Transistor structure of the device and that the noise depends on the concentration of the electrolyte and 1/f in nature. The statistical and frequency analysis of this electrochemical noise of a commercial ISFET sensor, under room temperature has been performed for six different pH values ranging from pH2 to pH9.2. The authors have also proposed a cocentration dependent a/f & b/f^sup 2^ model of the noise with different values of the coefficients a,b.