Influence of the aminated conditions on the pH sensitivity of silica and amorphous silicon film

Silicon nitride has been widely used as a pH sensitive membrane of the ion sensitive field effect transistor (ISFET) thanks to the high reactivity of the SiNH2 sites to the H+ ions. In this paper, we report experimental results on the H+ sensitivity of silica and amorphous silicon aminated films, obtained by the photo-CVD. We have studied the dependence of their response to pH as a function of the time and the temperature of amination of the film. The response of the aminated films (silica and amorphous silicon) is quasi-Nernstian for amination exposure time higher than 1 min, deposited at temperature lower than 200 degrees C. A theoretical model of deposition is presented. It can explain the influence of the deposition conditions. Published by Elsevier Science Limited.