Silicon oxidation and ultra-thin oxide formation on silicon studied by infrared absorption spectroscopy

An experimental method, based on infrared absorption spectroscopy, has been developed to study ultra-thin passivating layers on semiconductor surfaces . To characterize the interface of thin films, a two-pronged approach has b een used: thinning of the film to highlight the properties of the interfaci al layer and growth of the passivating film in a controlled fashion. In the latter approach IR spectroscopy is used at each growth step to probe the a toms both above and below the semiconductor surface. This approach is illus trated for the prototypical case of H2O reaction on Si(100)-(2 x 1), a syst em that provides a means to grow thin oxide films while following in great detail how oxygen is inserted into silicon and ultimately forms amorphous S iO2.