Sub-ångstrom experimental validation of molecular dynamics for predictive modeling of extended defect structures in Si.

In this Letter we present the detailed, quantitative comparison between experimentally and theoretically derived structures of the extended {311} defect in silicon. Agreement between experimental and theoretical column positions of better than ±0.05 nm has been achieved for all 100 atomic columns in the defect structure. This represents a calculated density of 5.5×10(14) silicon interstitials per cm(2) on {311} planes, in agreement with previous work [S. Takeda, Jpn. J. Appl. Phys., Part 2, 30, L639 (1991)]. We show that although the {311} defect is made up of five-, six-, seven-, and eight-member rings, the shape of these rings varies as a function of position along the defect, and these variations can be determined experimentally with high precision and accuracy. The excellent agreement between the calculated and experimentally derived structure, including the position of atomic columns and the shape of the distinct structural units of the defect, provides strong evidence for the quality and robustness of the molecular dynamics simulation approach for structural studies of defects. The experimental approach is straightforward, without the need for complicated image processing methods, and is therefore widely applicable.