Combined bulk and surface analysis of oxygen species in Si3N4 powders by means of carrier-gas heat-extraction methods and Auger electron spectrometry

Summary By means of the addition of 1%(v/v) C₂H₄ to He carrier gas and by application of a temperature ramp starting from 100°C in the carrier-gas heat-extraction technique, discrimination between two siloxane species in Si₃N₄ is feasible. By comparison with Auger electron spectrometry data, one species can be assigned to the surface and the other to bulk siloxane. This is demonstrated by means of two differently manufactured Si₃N₄ powders which are HF-etched or oxidized so that their — predominantly near-surface — oxygen content is decreased or increased, respectively. Additional oxygen speciation can be achieved by means of thermo-desorption of oxygen bound to hydrogen and carbon in Ar between room temperature and about 1000°C.