SPECTROSCOPIC ELLIPSOMETRY APPLIED TO THE DETERMINATION OF AN ION-IMPLANTATION DEPTH PROFILE

Spectroscopic ellipsometry (SE) has been used to characterise damage d epth profiles in silicon. The damage was produced by implantation of h igh energy ions of various atomic number with variable charge state an d using various energies. The effect of substrate temperature was also investigated. In all cases a first characterisation was made using Ru therford backscattering experiments. Attempts were then made to extrac t accurate data from SE measurements. If the damage depth profile is t hin (< 200 nm), a simulation of SE in the range 0.25-0.82 mu m using m ixed materials and a simple or complex depth profile can give very acc urate information. When the damage profile is thick enough (> 200 nm), an extended measurement in the near infrared (0.25-1.5 mu m) gives di rect information on the thickness of the damaged layer. In this latter case, data reduction is performed using Forouhi-Bloomer dispersion re lations for the amorphized silicon layer.