Strain evolution during the growth of epitaxial Ge layers between narrow oxide trenches

Byongju Kim, Sun Wook Kim, Hyunchul Jang, Jeong Hoon Kim, Sangmo Koo, Dae Hyun Kim, Byoung Gi Min, Se Jeong Park, Jason S. Song, Dae Hong Ko

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11 Citations (Scopus)

Abstract

We have grown the high quality and compressively strained Ge epilayers on a Si substrate with 40-nm width SiO2trench patterns at a growth temperature of 600 °C. Based on (224) reciprocal space mapping measurements of Ge samples with a different thickness, the residual in-plane strain value along the trench direction decreased from -0.74% to -0.42% with increasing thickness of the Ge layer from 150 nm to 180 nm. In addition, the compressive strain along the trench direction (ε1¯10) was larger than that in the direction perpendicular to the trench (ε110) regardless of the thickness. For example, when Ge was overgrown on a SiO2trench, the ε1¯10and ε110values were -0.42% and ~0%, respectively. We conclude that the asymmetric strain relaxation behavior of Ge is related to the SiO2trench patterns, which prevent the dislocations from gliding. Defects such as a microtwin and/or stacking fault were generated during the coalescence of Ge films having different lattice constants in each Ge layer arising from the different relaxation values. A local strain in Ge, with a high spatial resolution of 2.5 nm, was measured along the two directions by means of a nanobeam electron diffraction method, thus confirming asymmetric strain relaxation and the results are in good agreement with reciprocal space mapping results.

Original languageEnglish
Pages (from-to)308-313
Number of pages6
JournalJournal of Crystal Growth
Volume401
DOIs
Publication statusPublished - 2014 Sep 1

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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    Kim, B., Kim, S. W., Jang, H., Kim, J. H., Koo, S., Kim, D. H., Min, B. G., Park, S. J., Song, J. S., & Ko, D. H. (2014). Strain evolution during the growth of epitaxial Ge layers between narrow oxide trenches. Journal of Crystal Growth, 401, 308-313. https://doi.org/10.1016/j.jcrysgro.2013.12.057