First-principles study on the diffusion of B dopants in C-predoped Si = 탄소 원자가 주입된 실리콘 반도체에서 B 확산에 대한 제일원리 연구

The atomic structure and electronic properties of various defects consisting of B and C atoms in Si predoped with C impurities are investigated through first-principles density-functional calculations. In the absence of Si self-interstitials ($I_s$), substitutional B and C atoms interact repulsively with each other, implying that B-C pairs at neighboring substitutional sites do not play a role in the retardation of B diffusion. After examining various configurations for a $I_s-B-C$ complex, which can be formed in the excess of self-interstitials, it is found that a C-B split-interstitial, where the B and C atoms share a single lattice site along the [100] axis, is the most stable defect. For several diffusion pathways, along which the B dopant diffuses from the C-B split-interstitial complex with [100] orientation to nearby tetrahedral and hexagonal sites, very high migration energies of about 3 eV are calculated, which indicate that the diffusing B atom can be easily trapped in the neighborhood of C. The range of the C trap potential is estimated to be about 7 $\AA$. These results suggest that the suppression of B diffusivity in the presence of C is attributed to the formation of C-B split-interstitial complexes, in addition to the reduction of self-interstitials, which are available for B diffusion.
Advisors
Chang, Kee-Jooresearcher장기주researcher
Publisher
한국과학기술원
Issue Date
2009
Identifier
308627/325007  / 020073561
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 물리학과, 2009.2, [ vi, 21 p. ]

Keywords

Diffusion; Boron; Carbon; 확산; 붕소; 탄소

URI
http://hdl.handle.net/10203/48738
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=308627&flag=t
Appears in Collection
PH-Theses_Master(석사논문)
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