Identification of light elements in silicon nitride by aberration-corrected scanning transmission electron microscopy

In silicon nitride structural ceramics, the overall mechanical and thermal properties are controlled by the atomic and electronic structures at the interface between the ceramic grains and the amorphous intergranular films (IGFs) formed by various sintering additives. In the last ten years the atomic arrangements of heavy elements (rare-earths) at the Si3N4/IGF interfaces have been resolved. However, the atomic position of light elements, without which it is not possible to obtain a complete description of the interfaces, has been lacking. This review article details the authors' efforts to identify the atomic arrangement of light elements such as nitrogen and oxygen at the Si3N4/SiO2 interface and in bulk Si3N4 using aberration-corrected scanning transmission electron microscopy.

► Revealing the atomic structure of the α-Si3N4/SiO2 interface.
► Identification and lattice location of oxygen impurities in bulk α-Si3N4.
► Short range ordering of nitrogen and oxygen at the β-Si3N4/SiO2 interface.