A study was made of the type of information, concerning the surface layer structure of implanted Si after rapid thermal annealing, which could be acquired by using non-destructive methods such as X-ray diffractometry and reflection high-energy electron diffraction. Experiments were performed on crystals which had been implanted with Bi ions. The results showed that, by using the anomalous X-ray transmission of a wavelength of 0.154nm, it was possible to determine the defect concentration that was introduced by ion implantation to various doses, as well as the effect of annealing. There was a linear dependence, of the logarithm of the intensity of the transmitted beam, upon the logarithm of Bi ion doses of between 1014 and 5 x 1015/cm2. It was also shown that a surface layer of about 5nm remained amorphous after rapid thermal annealing. This was attributed to oxidation. Secondary ion mass spectrometric measurements revealed that, at the crystal surface, a small number of Bi atoms accumulated during rapid thermal annealing. After such annealing, most of the introduced Bi atoms occupied substitutional positions in lattice planes that were perpendicular to the sample surface. The positions of the maxima in the secondary ion mass spectrometric signals, which reflected the depth of the impurity distribution, were in good agreement with the ranges of Bi ions (with the same energies) that had been predicted by computer simulation. The measurements suggested that, at the crystal surface, the Bi atoms probably accumulated due to the redistribution of impurities that often occurred in disordered thin surface layers during rapid thermal annealing.

J.Auleytner, J.Adamczewska, A.Barcz, J.Górecka, K.Reginski: Crystal Research and Technology, 1995, 30[1], 129-33