A STUDY OF DEFECTS IN NANOSTRUCTURED AMORPHOUS-SILICON NITRIDE

Positron lifetime measurements have been performed in an investigation of nanostructured amorphous silicon nitride (NASN) for the first time . In NASN, the lifetimes tau1, tau2, and tau3 are attributed to vacanc y-size free volume in the interface, microvoids at the intersections o f interfaces and positronium formation in larger voids, respectively. Sintering treatment at high temperature can affect the behavior of the se components greatly. Our experimental results can prove that the cha nge of tau2 cannot be caused by the unpaired spins in dangling bonds, but by the change of interfacial microstructure. An attempt is made to elucidate how the interfacial microstructure affects the components. Besides the behavior Of tau1 and tau3 is also analyzed. The behavior o f the relative intensity I3 is related to the gas emission in the proc ess of sintering.