Silicon Systems

Si(001)

The research on Si(001) is currently focused on determining the origins of reflectance difference signals from Si(001) surfaces. We are currently using a technique, Reflectance Difference Spectroscopy (RDS), which measures the difference in the reflectance of orthogonal polarizations of light as a function of wavelength. This technique is very powerful because it has extreme chemical sensitivity and submonolayer resolution, and can be used in any transparent medium regardless of pressure. This last feature makes RDS especially useful as a companion to Chemical Vapor Deposition, where high pressures prevent one from using more conventional surface characterization techniques.

Presently, however, the utility of RDS is limited by the fact that the origin of the reflectance difference signal is poorly understood. To address this, experiments are being performed where the surface morphology is systematically modified and the resultant changes in the RD spectrum are observed. The RD spectral features will then be correlated to surface morphological features. This knowledge will help both in the use of RDS for surface characterization and in the theoretical modeling of the RD spectra produced by Si(001).