Sb lattice diffusion in Si1-xGex/Si(001) heterostructures: Chemical and stress effects
2004 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 69, no 15, 155415- p.Article in journal (Refereed) Published
The Sb diffusion coefficient in Si1-xGex/Si1-yGey(001) heterostructures grown by molecular beam epitaxy (MBE) was measured for temperatures ranging from 700 to 850 degreesC, Ge composition from 0 to 20 % and biaxial pressure from -0.8 (tension) to 1.4 GPa (compression). A quantitative separation of composition and biaxial stress effects is made. We show that the Sb lattice diffusion coefficient: (i) increases with Ge concentration in relaxed layers or at constant biaxial pressure and (ii) increases with compressive biaxial stress and decreases with tensile biaxial stress at constant Ge composition. The enhancement of Sb lattice diffusion in Si1-xGex layers in epitaxy on Si(001) is thus due to the cooperative effect of Ge composition and induced compressive biaxial stress. However, the first effect (composition) is predominant. The activation volume of Sb diffusion in Si1-xGex layers is deduced from the variation of the Sb diffusion coefficients with biaxial pressure. This volume is negative. The sign of the activation volume, its absolute value and its variation with temperature confirm the prediction of the thermodynamic model proposed by Aziz, namely, that under a biaxial stress the activation volume is reduced to the relaxation volume.
Place, publisher, year, edition, pages
2004. Vol. 69, no 15, 155415- p.
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:kth:diva-45009DOI: 10.1103/PhysRevB.69.155415ISI: 000221426800119ScopusID: 2-s2.0-42749099687OAI: oai:DiVA.org:kth-45009DiVA: diva2:451769
QC 201110272011-10-272011-10-262011-10-27Bibliographically approved