Separate structure extended gate H+-ion sensitive field effect transistor on a glass substrate

In our research, glass was used as a substrate for an H+ ion sensitive fiel d effect transistor (ISFET). The sensitive characteristics of five structur es for separate extended gate ion sensitive held effect transistors (EGFET) were studied. The components included tin oxide (SnO2)/aluminum/micro slid e glass, tin oxide/aluminum/corning glass, indium tin oxide (ITO) glass, ti n oxide/indium tin oxide glass and tin oxide/micro slide glass. Indium tin oxide (ITO) thin film was first time used as an H+ ion sensitive film, whic h has a linear pH Nerstern response sensitivity, about 58 mV/pH, between pH 2 and 12. In addition, the sensing area effect of the tin oxide/glass, tin oxide/ITO glass and ITO glass structure is discussed. The results show tha t the tin oxide/ITO glass structure EGFET has the best drift, hysteresis an d sensing area characteristics. (C) 2000 Elsevier Science B.V. All rights r eserved.