Study of the silicon nitride/aqueous electrolyte interface on colloidal aqueous suspensions and on electrolyte/insulator/semiconductor structures

Abstract

The silicon nitride/aqueous electrolyte interface has been studied on colloidal aqueous suspensions and on electrolyte/insulator/semiconductor (EIS) structures. Electrophoretic mobilities of the colloidal suspensions and capacitances of the EIS structures were measured. Before any previous exposure to water or after hydrogen fluoride etching, the silicon nitride surface shows a linear and Nernstian response for pH and its isoelectric point is 4. This behavior has been explained by the presence of a small fraction of amine groups at the silicon nitride surface. After exposure to water and to alkaline media, the silicon nitride surface behaves just like a silica surface for both systems. This is due to disappearance of the amine groups through a hydrolysis reaction.