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Segregation mechanism of arsenic dopants at grain boundaries in silicon.
- Source :
- Science & Technology of Advanced Materials; Dec2021, Vol. 22 Issue 1, p169-180, 12p
- Publication Year :
- 2021
-
Abstract
- Three-dimensional distribution of arsenic (As) dopants at Σ3{111}, Σ9{221}, Σ9{114}, and Σ9{111}/{115} grain boundaries (GBs) in silicon (Si) is examined by correlative analytical methods using atom probe tomography (APT) combined with low-temperature focused ion beam (LT-FIB), scanning transmission electron microscopy, and ab initio calculations. Σ3{111} GBs, consisting of only 6-membered rings with small bond distortions, do not exhibit an apparent As segregation. Meanwhile, it is hypothesized that As atoms would segregate at 5-membered rings in the other GBs via anisotropic bond distortions spontaneously introduced so as to lower the donor level, as Jahn-Teller distortions. In addition, APT combined with LT-FIB suggests preferential As segregation around stretched 1 1 ‾ 0 bonds reconstructed in Σ9{114} and Σ9{111}/{115} GBs, that are inevitably introduced in the 1 1 ‾ 0 tilt GBs with the tilt angle larger than 70.5°. It is hypothesized that As atoms would form As dimers at stretched 1 1 ‾ 0 bonds and the adjacent ⟨ 111 ⟩ bonds, due to the tendency of As with five valence electrons to form a three-coordinated configuration, which is efficiently attained by an As dimer of a long length. This work provides important insights into As segregation at GBs; it is mainly determined by electronic interactions depending on the characteristics of valence electrons of As atoms, as well as on local bond distortions at GBs, via anisotropic bond distortions and dimerization. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14686996
- Volume :
- 22
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Science & Technology of Advanced Materials
- Publication Type :
- Academic Journal
- Accession number :
- 157904275
- Full Text :
- https://doi.org/10.1080/27660400.2021.1969701