Abstract
In this paper, we study the nucleation of dislocations and their subsequent propagation, during thin film deposition, using the three-dimensional (3D) molecular dynamics (MD) method. Aiming to reveal the generic mechanisms, the case of tungsten on a substrate of the same material is investigated. The substrate is under uniaxial compression along the [1 1 1] direction, with the thermodynamically favored (0 1̄ 1) surface being horizontal. The simulation results indicate that the nucleation starts with a surface step where an atom is squeezed to the layer above, generating a half-dislocation loop at the surface. It may then either propagate into the film or become the bottom of a sessile dislocation loop. In the first case, the dislocation loop, having a Burgers vector 1/2[1 1̄ 1̄] on a (1 0 1) glide plane, propagates along the [1 1̄ 1̄] direction on the surface, and extends to about two atomic layers along the [1 1 1] direction. In the second case, the missing layer propagates along the [1 0 0] direction on the surface, extending to about four atomic layers along the [1 1 1] direction. In this case, the sessile dislocation has a Burgers vector 1/2[1̄ 1̄ 1̄] on the plane (0 1 1).
Original language | English |
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Pages (from-to) | 155-165 |
Number of pages | 11 |
Journal | Computational Materials Science |
Volume | 23 |
Issue number | 1-4 |
DOIs | |
Publication status | Published - 1 Apr 2002 |
Keywords
- Dislocation nucleation
- Dislocation propagation
- Molecular dynamics
- Thin films
ASJC Scopus subject areas
- General Computer Science
- General Chemistry
- General Materials Science
- Mechanics of Materials
- General Physics and Astronomy
- Computational Mathematics