Optical techniques for probing semiconductor surfaces and interfaces

The increasing importance of semiconductor surfaces and interfaces has led to the development of a range of optical probes for their characterisation. In this paper, some recent results of the linear and nonlinear optical response from well characterised GaAs and Si surfaces are presented. Reflectance anisotropy spectroscopy (RAS) is shown to be capable of monitoring semiconductor growth with monolayer precision and optical second harmonic generation (SHG) provides surface structural information. RAS studies of the growth of GaAs on GaAs(001) by chemical beam epitaxy (CBE) in spectroscopic and dynamic mode display, respectively, that the RAS response is sensitive to surface reconstruction and to monolayer growth. Spectroscopic SHG from on-axis Si(001)1x2, Si(001)1x1-Sb and Si(001)2x1-Sb surfaces in the region of 3.3eV was investigated and information is obtained which supports the model of Cricenti et al [1] for the controversial Si(001)1x1-Sb structure.