Miles, R. H. and Chow, P. P. and Johnson, D. C. and Hauenstein, R. J. and Marsh, O. J. and Nieh, C. W. and Strathman, M. D. and McGill, T. C. (1988) Accommodation of lattice mismatch in Ge_(x)Si_(1−x)/Si superlattices. Journal of Vacuum Science and Technology B, 6 (4). pp. 1382-1385. ISSN 1071-1023 http://resolver.caltech.edu/CaltechAUTHORS:20120607-134521339
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We present evidence that the critical thickness for the appearance of misfit defects in a given material and heteroepitaxial structure is not simply a function of lattice mismatch. We report substantial differences in the relaxation of mismatch stress in Ge_(0.5)Si_(0.5)/Si superlattices grown at different temperatures on (100) Si substrates. Samples have been analyzed by x‐ray diffraction, channeled Rutherford backscattering, and transmission electron microscopy. While a superlattice grown at 365 °C demonstrates a high degree of elastic strain, with a dislocation density <10^5 cm^(−2) , structures grown at higher temperatures show increasing numbers of structural defects, with densities reaching 2×10^(10) cm^(−2) at a growth temperature of 530 °C. Our results suggest that it is possible to freeze a lattice‐mismatched structure in a highly strained metastable state. Thus it is not surprising that experimentally observed critical thicknesses are rarely in agreement with those predicted by equilibrium theories.
|Additional Information:||© 1988 American Vacuum Society. Received 3 February 1988; accepted 10 May 1988. One of us (R.KM.) is grateful for financial support from IBM. The authors wish to acknowledge the partial support of the Defense Advanced Research Projects Agency monitored by the Office of Naval Research under Contract No. N00014-84-C-0083. One of us (C.W.N.) acknowledges the support of the National Science Foundation under Grant No. DMR-8421119.|
|Subject Keywords:||Thickness; crystal defects; dislocations; interface structure; high temperature; x-ray diffraction; germanium silicides; silicon; strains; RBS; transmission electron microscopy; superlattices; heterostructures; epitaxy; fabrication|
|Classification Code:||PACS: 68.65.-k; 68.55.Ln; 68.35.Dv; 68.55.-a|
|Official Citation:||Accommodation of lattice mismatch in Ge[sub x]Si[sub 1 - x]/Si superlattices R. H. Miles, P. P. Chow, D. C. Johnson, R. J. Hauenstein, O. J. Marsh, C. W. Nieh, M. D. Strathman, and T. C. McGill, J. Vac. Sci. Technol. B 6, 1382 (1988), DOI:10.1116/1.584226|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||07 Jun 2012 21:36|
|Last Modified:||26 Dec 2012 15:19|
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