DAMAGE ANALYSIS AND OPTICAL-PROPERTIES OF GE-IMPLANTED SILICON

The damage produced in crystalline silicon by Ge-ion implantation at 130 keV is studied as a function of fluence. Rutherford backscattering measurements in channeling configuration and reflectivity measurements in the 1.5-6.5 eV energy range are presented and discussed. The results obtained by both techniques are in agreement on the determination of the amorphization threshold. The dielectric functions, obtained by the Kramers-Kronig analysis and checked through ellipsometric measurements at one selected wavelength, are well reproduced by finite sets of classical harmonic oscillators. It is possible to describe the behavior of the oscillator parameters through analytical functions of a single variable related to the amount of damage. In a representative case, the damage depth profile is obtained after the removal of controlled amounts of silicon by anodic oxidation, and good agreement is found with the Rutherford backscattering results.