DETECTION OF THIN INTERGRANULAR FILMS BY ELECTRON-MICROSCOPY

The presence of very thin (6-50 Å) films in integrated circuits and separating crystalline grains in ceramics, notably in zinc oxide varistors and in silicon nitride, has recently been reported using high resolution electron microscopy. The geometric conditions that must be met in order to observe such thin intergranular films using the microscopy techniques of bright-field imaging and lattice-fringe imaging, already adopted, are described. In addition, a method of defocus imaging is applied for the first time to the detection of thin films at grain boundaries. © 1979.