ANISOTROPIC REFLECTANCE FROM SEMICONDUCTOR SURFACES FOR IN-SITU MONITORING IN EPITAXIAL-GROWTH SYSTEMS

Spectroscopy of the anisotropic part of the reflectance (reflectance a nisotropy spectroscopy: RAS or reflectance difference spectroscopy: RD S) is a promising diagnostic technique for real-time studies of semico nductor surfaces during epitaxial growth. This in-situ technique turns our to be highly sensitive to the status of the surface and, moreover , requires only slight modifications to standard epitaxial growth syst ems. In this paper, RAS studies of semiconductor epitaxial growth are reviewed and state-of-the-art results are reported. Primarily, spectra from III-V semiconductors are discussed in terms of surface bonds and surface reconstructions. Time-resolved measurements allow to study th e dynamics of surface processes such as exchange reactions which are i mportant for the optimisation of heterointerfaces. Furthermore, the os cillatory behaviour of the island growth mode shows up in the RAS sign al and can be utilized for growth rate monitoring and in-situ measurem ent of composition. The combination of these features allows, for exam ple, the control of the growth of a superlattice on a submonolayer sca le.