ION-IMPLANTATION-CAUSED SPECIAL DAMAGE PROFILES DETERMINED BY SPECTROSCOPIC ELLIPSOMETRY IN CRYSTALLINE AND IN RELAXED (ANNEALED) AMORPHOUS-SILICON

We previously developed a fitting method of several parameters to eval uate ion-implantation-caused damage profiles from spectroscopic ellips ometry (SE) (M. Fried et al., J. Appl. Phys., 71 (1992) 2835). Our opt ical model consists of a stack of layers with fixed and equal thicknes ses and damage levels described by a depth profile function (coupled h alf Gaussians). The complex refractive index of each layer is calculat ed from the actual damage level by Bruggeman effective medium approxim ation (EMA) using crystalline (c-Si) and amorphous (a-Si) silicon as e nd-points. Two examples are presented of the use of this method with m odified optical models. First, we investigated the surface damage form ed by room temperature B+ and N+ implantation into silicon. For the an alysis of the SE data we added a near surface amorphous layer to the m odel with variable thickness. Second, we determined 20 keV B+ implanta tion-caused damage profiles in relaxed (annealed) amorphous silicon. I n this special case, the complex refractive index of each layer was ca lculated from the actual damage level by the EMA using relaxed a-Si an d implanted a-Si as end-points. The calculated profiles are compared w ith Monte Carlo simulations (TRIM code); good agreement is obtained.