Accommodation of lattice mismatch in GexSi1−x/Si superlattices
作者:
R. H. Miles,
P. P. Chow,
D. C. Johnson,
R. J. Hauenstein,
O. J. Marsh,
C. W. Nieh,
M. D. Strathman,
T. C. McGill,
期刊:
Journal of Vacuum Science&Technology B: Microelectronics Processing and Phenomena
(AIP Available online 1988)
卷期:
Volume 6,
issue 4
页码: 1382-1385
ISSN:0734-211X
年代: 1988
DOI:10.1116/1.584226
出版商: American Vacuum Society
关键词: THICKNESS;CRYSTAL DEFECTS;DISLOCATIONS;INTERFACE STRUCTURE;HIGH TEMPERATURE;X−RAY DIFFRACTION;GERMANIUM SILICIDES;SILICON;STRAINS;RBS;TRANSMISSION ELECTRON MICROSCOPY;SUPERLATTICES;HETEROSTRUCTURES;EPITAXY;FABRICATION;Si;(Ge,Si)
数据来源: AIP
摘要:
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 Ge0.5Si0.5/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<105cm−2, structures grown at higher temperatures show increasing numbers of structural defects, with densities reaching 2×1010cm−2at 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.
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