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 been used: thinning of the film to highlight the properties of the interfacial 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 atoms both above and below the semiconductor surface. This approach is illustrated for the prototypical case of H2O reaction on Si(100)-(2 x 1), a system that provides a means to grow thin oxide films while following in great detail how oxygen is inserted into silicon and ultimately forms amorphous SiO2.