Drift behavior of ISFETs with a-Si : H-SiO2 gate insulator

In this study, the hydrogenated amorphous silicon (a-Si:H) which was fabric ated by plasma-enhanced low-pressure chemical vapor deposition (PE-LPCVD) w as used as a pH-sensitive surface and the drift behavior of ISFET was measu red. To avoid the long-term drift, the ISFET was dipped in temperature-cont rolled standard buffer solution of pH 1, 3, 5, and 7 in closed dark box. Ac cording to these experiments, we can obtain that the drift rate depends on the pH value and increases with the pH increasing. Furthermore, the tempera ture of the buffer solution was changed and we obtained that drift rate sho ws an increase which can be calculated by the exponential expression. (C) 2 000 Elsevier Science S.A. All rights reserved.