Surface Studies on Single-Crystal Germanium

The condition of the surface of germanium crystals has been studied by chemical, electron microscope, electron diffraction, and other techniques after several of the standard etching procedures. The surface is often partially covered by particles believed to be germanium monoxide. An etch has been devised which gives a controlled thickness of germanium monoxide on the crystal. Another etch minimizes the oxide formation. A simple light-scattering method for checking the surface cleanliness is described. The results of surface recombination velocity and channel effect measurements on crystals treated by these methods are described as is a method for obtaining low surface recombination on n-type crystals.