AVS 50th International Symposium
    Surface Science Tuesday Sessions
       Session SS2-TuM

Paper SS2-TuM10
High-Temperature Low Energy Electron Microscopy Studies of Spiral Dislocation Dynamics on TiN(111) Terraces

Tuesday, November 4, 2003, 11:20 am, Room 328

Session: Nucleation and Growth
Presenter: S. Kodambaka, University of Illinois at Urbana-Champaign
Authors: S. Kodambaka, University of Illinois at Urbana-Champaign
S.V. Khare, University of Illinois at Urbana-Champaign
W. Swiech, University of Illinois at Urbana-Champaign
K. Ohmori, University of Illinois at Urbana-Champaign
I. Petrov, University of Illinois at Urbana-Champaign
J.E. Greene, University of Illinois at Urbana-Champaign
Correspondent: Click to Email
We have grown epitaxial TiN(111) layers by reactive evaporation onto Al@sub 2@O@sub 3@(0002) substrates and used in situ high-temperature low-energy electron microscopy to study surface morphological evolution on large (> 4 µm) atomically-smooth TiN(111) terraces during annealing at temperatures T@sub a@ in the range 1500 and 1750 K (T@sub a@ = 0.47-0.55T@sub m@, where T@sub m@ is the melting point in K). At each annealing temperature, we observe rotation of screw dislocation segments lying in the surface slip plane around the immobilized segment of the dislocation lying out of the slip plane resulting in a spiral with steps oriented along <110>. Step heights are proportional to the number of revolutions in the slip plane. We find that the total length of the dislocation line increases with annealing time as the spirals undergo a shape-preserving anti-clockwise motion with a constant angular velocity. From the temperature-dependent angular velocity measurements, we determine an activation barrier of 5.0±0.2 eV, with a prefactor of 10@super 14+/-0.5@ s@super -1@, for spiral rotation. Studies of this process, a single-ended Frank-Read source, provide insight into understanding dislocation multiplication mechanisms occurring in highly refractory, technologically important transition-metal nitride layers.