In high resolution observation of ultra-fine uneven surfaces of specimens, the image of replica films obtained by the normal single-stage replica method on specimen surfaces with uneven structure, less than 10nm in size, is deformed by the evaporated materials, even though the thickness of the evaporated film is only a few nm. Therefore, the smallest size of a replicated square-shaped object, that can be recognized as square shaped one, is about 5×5nm².
In the new method, the unevenness of specimen surfaces is covered with evaporated film by conventional vacuum evaporation. As a result, fine details of surface structures are correctly removed with little deformation and are clearly observed in the replica image.
The smallest square shaped object, of 1.12×1.12nm² size, that appeared in the replica image, is twice as large as the unit cell of NaCl crystal.