Cross Sectional Transmission Electron Microscopy Study of Obliquely Evaporated Silicon Oxide thin Films

ABSTRACTThe columnar structure in obliquely evaporated silicon oxide layers was investigated by transmission electron microscope (TEM). For TEM studies of these layers, samples were made by low angle ion-beam thinning of cross-sections, the planes of which were determined by the normal of the film and the direction of evaporation. Increasing the angle of evaporation from 5° to 30° (measured from the plane of the substrate), a change from a well–defined columnar structure to a striated structure was observed, for layers evaporated both under “low-rate” and “high-rate” conditions. There is a clear-cut dependence of the orientation of columns (αc) upon the angle of evaporation (α), however deviating from the “tangent rule” (tanαc=2tanα).