Hydrogen ion diffusion in silicon nitride thin film was of significant interest because of its importance in barrier, sensor and catalytic coating applications. A novel method based

upon potential–pH response measurement was used here to determine H ion diffusion in silicon nitride thin films. The H-ion diffusion coefficient in silicon nitride films obtained by using this method was 10-19cm2/s. A potential–pH response drift was observed and was believed to be due to the presence of a hydrated layer affecting the H ion diffusion onto the nitride film of the Si3N4-gate H ion-sensitive field effect transistors. The unique feature of the potential–pH response method was its relatively simple experimental procedure, which eliminates complications arising from surface-related effects and/or presence of H traps in membrane, such as those found in the conventional permeation method. The method also offers a considerable test time reduction, with the experiment being completed in 10h as compared with the conventional electrochemical permeation method which took as long as 120h.

Hydrogen Ion Diffusion Coefficient of Silicon Nitride Thin Films. G.T.Yu, S.K.Yen: Applied Surface Science, 2002, 202[1-2], 68-72