Tools for probing `atomic¿ action: Device designers need sophisticated ways to examine the advanced structures they have created

The growth of thin films by vapor deposition, patterning by electron-beam lithography, and doping by low-energy ion implantation have opened the way to microelectronics on an incredibly fine scale. Newer microscopes that take advantage of the much lower wavelength associated with electrons are now available to build and study the new, minute electronic devices. The capabilities of the transmission electron microscope, the scanning transmission electron microscope, the scanning tunneling microscope, and the field ion microscope are surveyed. Problems posed by spherical aberration and by the need to stabilize the image are discussed. Attention is also given to the ability of high-resolution electron microscopes to provide information on interfaces.