Strain relaxation of thin Si0.6Ge0.4 grown with low-temperature buffers by molecular beam epitaxy
2009 (English)In: JOURNAL OF APPLIED PHYSICS, ISSN 0021-8979 , Vol. 105, no 6, 063502- p.Article in journal (Refereed) Published
A double-low-temperature-buffer variable-temperature growth scheme was studied for fabrication of strain-relaxed thin Si0.6Ge0.4 layer on Si(001) by using molecular beam epitaxy (MBE), with particular focuses on the influence of growth temperature of individual low-temperature-buffer layers on the relaxation process and final structural qualities. The low-temperature buffers consisted of a 40 nm Si layer grown at an optimized temperature of similar to 400 degrees C, followed by a 20 nm Si0.6Ge0.4 layer grown at temperatures ranging from 50 to 550 degrees C. A significant relaxation increase together with a surface roughness decrease both by a factor of similar to 2, accompanied with the cross-hatch/cross-hatch-free surface morphology transition, took place for the sample containing a low-temperature Si0.6Ge0.4 layer that was grown at similar to 200 degrees C. This dramatic change was explained by the association with a certain onset stage of the ordered/disordered growth transition during the low-temperature MBE, where the high density of misfit dislocation segments generated near surface cusps largely facilitated the strain relaxation of the top Si0.6Ge0.4 layer.
Place, publisher, year, edition, pages
2009. Vol. 105, no 6, 063502- p.
buffer layers, dislocations, Ge-Si alloys, molecular beam epitaxial growth, order-disorder transformations, semiconductor growth, semiconductor materials, semiconductor thin films, surface morphology, surface roughness
National CategoryNatural Sciences
IdentifiersURN: urn:nbn:se:liu:diva-17893DOI: 10.1063/1.3091266OAI: oai:DiVA.org:liu-17893DiVA: diva2:212982
Ming Zhao, Göran Hansson and Wei-Xin Ni, Strain relaxation of thin Si0.6Ge0.4 grown with low-temperature buffers by molecular beam epitaxy, 2009, JOURNAL OF APPLIED PHYSICS, (105), 6, 063502.
Copyright: American Institute of Physics