CHARACTERIZATION OF SILICON SURFACES AND INTERFACES BY OPTICAL VIBRATIONAL SPECTROSCOPY

Chemical reactions at semiconductor surfaces and interfaces can be indirectly studied by characterizing the surface species with vibrational spectroscopy. We review here the various optical techniques available to study surface and interfacial adsorbates including both linear techniques, such as infrared absorption and Raman scattering, and nonlinear techniques, such as sum-frequency generation. We also review the different optical geometries appropriate to each technique. These methods differ dramatically in both their overall sensitivity to surface adsorbates as well as their sensitivity to adsorbate geometries as obtained from calculations of the local surface electric field and oscillator response. Illustrative examples from recent studies of the interfacial chemistry of bonded wafers as well as structural studies of HF-etched silicon surfaces are presented. © 1995, American Vacuum Society. All rights reserved.