1/f noise in ion sensitive field effect transistors from subthreshold to saturation

The present paper presents extensive measurements of low frequency noise in pH ion sensitive field effect transistors (ISFET's) under various bias conditions corresponding to the gate voltage changing from subthreshold to saturation, in the frequency range between 1 Hz and 100 kHz. The noise measurements were performed in solutions with pH in the range of pH4 to pH10, at room temperature. In contrast to previously reported results, the measured ISFET's exhibit clearly 1/f noise down to 1 Hz.