The hysteresis and drift effect of hydrogenated amorphous silicon for ISFET

The time-dependent response of the output voltage of pH-sensitive ion sensitive field effect transistors(pH-ISFETs) has been observed. According to the experimental results, the output behavior of the device consists of four parts : fast response, slow response, drift and hysteresis. The hysteresis and drift limit the accuracy obtained from pH-ISFET. In this paper, we prepared the hydrogenated amorphous silicon (a-Si:H) as the pH-sensitive material. We have studied that the hysteresis effects in a-Si:H-gate ISFETs by exposing the device to two cycles of pH values and compared the hysteresis amounts. In addition, we have measured the drift effect of a-Si:H at the different pH values and understand the influence of pH values for the drift effect of a-Si:H-gate ISFETs.