Hostname: page-component-5c6d5d7d68-xq9c7 Total loading time: 0 Render date: 2024-08-22T02:10:10.034Z Has data issue: false hasContentIssue false
  • English
  • Français

Emission of a Half-Rectangular Dislocation Loop from the Surface of a Compositionally Graded Epilayer

Published online by Cambridge University Press:  21 February 2011

Tong-Yi Zhang
Tong-Yi Zhang*
Affiliation:
Department of Mechanical Engineering Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong
Get access

Abstract

When a half-rectangular perfect or partial dislocation loop is emitted from the surface of a strained epilayer, the optimum dislocation shape occurs at a saddle point of the total energy profile as a function of the dislocation width and length. The activation energy and the optimum shape are calculated for either a compositionally graded or uniform epilayer. The results indicate that 1) dislocation emission is more difficult in a compositionally graded layer than in a compositionally uniform layer; and 2) the ratio of threading dislocation density to mismatch dislocation density is lower in a compositionally graded layer than in a compositionally uniform layer. Theoretical results agree with experimental observations [1,2].

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 356: Symposium B2 – Thin Films: Stresses and Mechanical Properties V , 1994 , 289
Copyright
Copyright © Materials Research Society 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Fitzgerald, E.A., Xie, Y.-H., Monroe, D., Silverman, P.J., Kuo, J.M., Kortan, A.R., Thiel, F.A., and Weir, B.E., J. Vac. Sci. Technol. B 10, 1807 (1992).Google Scholar
2. LeGoues, F.K., Meyerson, B.S., and Morar, J.F., Phys. Rev. Lett. 66, 2903 (1991).Google Scholar
3. Tersoff, J., Appl. Phys. Lett. 62, 693 (1993).Google Scholar
4. Mathews, J.W., J. Vac. Sci. Technol. 12, 126 (1975).Google Scholar
5. Kamat, S.V. and Hirth, J.P., J. Appl. Phys. 67, 6844 (1990)Google Scholar
6. Zhang, T.-Y., “Emission of a half-rectangular dislocation loop from a mode I crack tip”, submitted to J. Materials Research.Google Scholar
7. Hirth, J.P. and Lothe, J., Theory of Dislocations, 2nd ed., Wiley, New York 1982.Google Scholar
8. Zhang, T.-Y., “A dislocation in a compositionally graded epilayer”, submitted to Phys. Stat. Sol.Google Scholar
9. Barrett, C.S. and Massalski, T.B., Structure of Metals, 3rd ed., Pergamon, Oxford 1980.Google Scholar
10. Alexander, H., in “Dislocations in Solids”, Vol. 7, Chap. 35, ed. Nabarro, F.R.N., North-Holland, Amsterdam 1986.Google Scholar