When measuring pattern widths, etc., it is necessary to measure without specimen tilting or to correct values obtained from a tilted state. In such cases, observation of stereo SEM images makes it easier to understand the structure of the specimen. What is more, stereo observation allows unexpected information to be obtained even from specimens of simple structure. Viewing these two photos using stereo glasses with the tilting axis held vertically, provides a stereo image. Back sides of oleaster leaves.
More information is obtained from stereo-palr photos.
The amount of secondary electrons produced when the specimen is illuminated with an electron beam, depends on the angle of incidence theoretically. However, there arises a difference in the image brightness depending on whether the tilted side of the specimen is directed to the secondary electron detector or the opposite side. With a long specimen, for example, the brightness differs between the side facing the detector and the opposite side. In such a case, directing the longitudinal axis of the specimen to the detector makes the brightness uniform. Directing the longitudinal axis of the specimen to the secondary electron detector makes the right and left sides equally bright.