Step-graded buffer layer study of the strain relaxation by transmission electron microscopy

✍ Scribed by D. González; D. Araújo; S.I. Molina; A. Sacedón; E. Calleja; R. García

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 972 KB
• Volume: 28
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/0921-5107(94)90114-7

✦ Synopsis

The lattice relaxation behavior in an InxGal_xAs/GaAs linearly step-graded structure is studied by transmission electron microscopy (TEM). From the misfit dislocation densities measured by TEM at each interface the relaxation parameters such as strain and percentage relaxation are deduced for each layer. The obtained results are compared with the predictions of the Dunstan et al. model which describe the dislocation behavior during relaxation in such structures. A different relaxation behavior than that described by Dunstan et al. is observed. This is attributed to the fact that the individual layer thickness is lower than the critical layer thickness of Dunstan et al. Work-hardening processes are found to induce a linear increase in the residual strain with increasing layer thickness.