The creation of silicon nitride coatings by successive gas-phase reactions with trichlorosilane and ammonia : chemical surface coating : a new route towards thin ceramic layers on silica

Abstract

The technique of Chemical Surface Coating consists of subsequent, consecutive reactions of different reagents with the surface of a substrate. This article presents an overview of the creation of a stable Si-N coating, by means of a reaction cycle of trichlorosilane and ammonia with the surface of silica gel. The reactions involved are much more complex than often believed. Upon trichlorosilylation of tile silica, at least 5 different surface species are created; after ammoniation, at least 6 different surface species are present on tile silica surface. These species have been characterized by FTIR, Si-29 CP MAS NMR and by XPS. At 840 degrees C, more than 60% of the nitrogen functions, present on the surface, are in the form of nitrides