DISTRIBUTION OF STRAIN IN GE ION-IMPLANTED SILICON MEASURED BY HIGH-RESOLUTION X-RAY-DIFFRACTION

The strain due to implantation of Ge ions into silicon wafers was measured by high resolution X-ray diffractometry. (001) and (111) oriented Si wafers were implanted with 320 and 640 keV Ge ions at different doses. The measured rocking curves were compared with simulations based on the dynamical theory of diffraction. We find that the strain in the Si wafers can be described by a linear combination of strain proportional to the implanted ion distribution and of strain proportional to the radiation damage distribution. At low doses (almost-equal-to 10(13) cm-2) the strain profile is given by the damage profile, at high dose (greater than or similar to 10(14) cm-2) the Strain profile follows the ion distribution. The maximum strain increases roughly linear with dose until amorphization occurs. Rapid thermal annealing experiments reveal that the damage related strain disappears at temperatures of 700-800-degrees-C. Further annealing at temperatures up to 1050-degrees-C is necessary to remove also the ion related strain.