R.B.S. Microscopic "Tomography"

The resolving power of optical and electron microscopes is limited by diffraction, scattering being also a problem with electron microscopes, and ion source properties in the case of ion microprobes. Essentially, the resolution is determined by the hardware. We have developed a technique involving simple equipment but extensive computer analysis following the taking of data. The profile and internal constitution of periodic surfaces and micron sized objects is measured by irradiating them uniformly with a parallel beam of ions. The Rutherford backscattered spectra, observed at different angles using solid state detectors, are analyzed in a manner similar to that employed in tomography to yield the structure of the object irradiated. The ultimate resolution is determined by ion straggling, rather than diffraction.