Surface Studies by Spectral Analysis of Internally Reflected Infrared Radiation: Hydrogen on Silicon

An investigation of the adsorption of hydrogen on a large single crystal of silicon has been made by infrared methods in an ultrahigh vacuum system. A broad absorption line at 4.85 μ has been ascribed to a monolayer of atomic hydrogen chemisorbed on clean silicon. The increase in intensity and changes in position and shape of this line produced by hydrogen ion bombardment are reported. The primary purpose of this work was to evaluate the technique of spectral analysis of infrared radiation multiply internally reflected in a semiconductor as a general tool for the study of adsorption on clean semiconductor surfaces. It is concluded that the method can indeed be useful in favorable cases, although formidable experimental difficulties stand in the way of a very general application.