Study on the temperature effect, hysteresis and drift of pH-ISFET devices based on amorphous tungsten oxide

In this paper, the drift, hysteresis and temperature effect of ISFET devices have been studied. Drift behavior exists in the whole measurement, and hysteresis behavior is affected by slow response. These two properties limit the accuracy of ISFET. Furthermore, some characteristics such as pH sensitivity and drift are affected by operating temperature. The I–V curves of a-WO3 gate ISFET was obtained at different temperatures and the pH sensitivities were calculated in the acid buffer solutions. In the measuring processes, the operating temperatures were 25, 35, 45, 55 and 65°C, respectively, and according to the experimental results, we can find that the pH sensitivity increases with increasing temperature, the hysteresis effect is dependent on measuring loop time and measuring path, and the drift increases with increasing pH value.