ATOMIC STRUCTURE OF EXTENDED DEFECTS IN BORON-IMPLANTED SILICON LAYERS
L. I. Fedina1, A. K. Gutakovskii1, A. V. Latyshev1,2
1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent’eva 13, Novosibirsk, 630090 Russia
2Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia
Keywords: boron implantation, extended defects, vacancy deficit, HREM
Abstract
The structure of extended defects introduced into Si by means of boron implantation followed by thermal annealing at T = 900 ºC is studied by the method of high-resolution transmission electron microscopy and computer modeling for different values of the implantation dosage (D) and concentration of boron atoms in substitutional positions B0(CB0) injected into the Si lattice before implantation. It is shown that the Frank dislocation loops of both interstitial (I) and vacancy (V) type at a ratio of 4 : 1 are observed in Si samples with D = 1016 cm−2 up to CB0 = 0.8 · 1020 cm−3. The atomic structure of the I-type Frank dislocation loops is heavily deformed, which suggests segregation of finely dispersed boron in the defect plane. At the same time, the structure of the V-type Frank dislocation loops tends to be reconstructed due to interaction with self-interstitials. At C B0 = 2.5 · 1020 cm−3, the I-type Frank dislocation loops are found to transform to perfect dislocation loops, and boron precipitates with a high density appear in Si. Based on the results obtained, probable reasons for vacancy deficit formation in boron-implanted Si are discussed.
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