Micro-Probe Reflection High-Energy Electron Diffraction Technique. I. Determination of Crystallographic Orientations of Polycrystal-Silicon Surfaces

A micro-probe reflection high-energy electron diffraction (RHEED) apparatus including an electron gun with a probe size of 0.1 µm operated under ultrahigh vacuum, has been constructed. This makes it possible to obtain bright, sharp diffraction patterns from micro-areas of clean surfaces, and to take RHEED-microscope images of crystal surfaces. Using this apparatus, a technique for determining the crystallographic orientations of surface micro-areas within an accuracy of ±1° has been developed. This is done by analyzing Kikuchi patterns emitted at low angles, and spatial distributions having various crystallographic orientations are obtained by taking RHEED-microscope images. From the results of applying this technique to polycrystal-Silicon surfaces, it is found that it is very useful in determining the crystallographic orientations of surface micro-areas.