Strain compensated heterostructures in the Si1−x−yGexCy ternary system

Régolini, J. L.; Bodnar, S.; Oberlin, J.C.; Ferrieu, F.; Gauneau, M.; Lambert, B.; Boucaud, P.

doi:10.1116/1.579277

Cited by 46 publications

(10 citation statements)

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“…4,5 Much attention has also been focused on SiGe in band-edge engineering for optoelectronic devices, 6 where Ge-rich alloys are of particular interest. 7 Omnipresent contaminants like hydrogen atoms 8,9 may significantly modify the electronic properties of semiconductor materials. For example, hydrogen atoms form complexes with dopant atoms in silicon, [10][11][12] leading to the neutralization of their electronic activity, which is crucial in semiconductor-based technology.…”

Section: Introductionmentioning

confidence: 99%

Antibonding configurations of hydrogen in silicon-germanium alloys

Pereira

Nielsen

Peaker³

et al. 2006

Phys. Rev. B

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Defects with a hydrogen atom at an antibonding site are identified in germanium-rich SiGe alloys ͑Ge 1−x Si x ͒ implanted with protons at low temperatures. Infrared absorption spectra of proton-implanted Ge 1−x Si x reveal hydrogen-related absorption lines, which are similar to those observed previously in pure germanium, together with three unreported absorption lines. For crystals with a silicon content of 1.2 at. % these three lines are observed at 815.8, 1430.2, and 1630.7 cm −1 . The three lines are ascribed to the wag mode, the stretch mode, and to the first overtone of the wag mode, respectively, of the negatively charged state of a hydrogen atom located at an antibonding site and attached to a substitutional silicon atom. The assignment is based on the comparison between the observed frequencies and those known for similar structures, the variation of line intensities with the alloy composition, the absorption frequency shifts resulting when hydrogen is replaced by deuterium, and the thermal stability of the absorption lines, as well as comparison with the results of ab initio calculations. A conversion process takes place at temperatures in the range 20-125 K between negatively charged hydrogen at a germanium antibonding site to a silicon antibonding site. This provides direct evidence that silicon acts as an effective trap for negatively charged hydrogen in SiGe alloys. Based on the data obtained for samples with different silicon contents we give an estimate of the low temperature diffusion length of hydrogen in Ge-rich SiGe before it becomes trapped at an antibonding site attached to Ge and discuss why local vibrational modes of negatively charged hydrogen remain unobserved for silicon and silicon-rich SiGe alloys.

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Section: Introductionmentioning

confidence: 99%

Antibonding configurations of hydrogen in silicon-germanium alloys

Pereira

Nielsen

Peaker³

et al. 2006

Phys. Rev. B

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“…The strain in a Si 1Ϫx Ge x layer can be compensated, if C atoms are added to the alloy. 3 Highquality Si 1ϪxϪy Ge x C y layers, several hundred nanometers thick, have been obtained by nonequilibrium techniques, such as molecular-beam epitaxy ͑MBE͒, 4,5 combined ion and molecular-beam deposition, 6 chemical vapor deposition, [7][8] and ion implantation followed by solid-phase regrowth. 9 In these alloys, most of the C atoms are believed to be located at substitutional sites.…”

Section: Introductionmentioning

confidence: 99%

Substitutional carbon inSi1−xGex

et al. 1999

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Local vibrational modes of carbon impurities in relaxed Si 1Ϫx Ge x have been studied with infrared absorption spectroscopy in the composition range 0.05рxр0.50. Carbon modes with frequencies in the range 512-600 cm Ϫ1 are observed in 13 C ϩ -implanted Si 1Ϫx Ge x after annealing at 550°C. Measurements on samples coimplanted with 12 C ϩ and 13 C ϩ show that these modes originate from defects containing a single carbon atom and from the variation of the mode frequencies with composition x, the modes are assigned to substitutional carbon in Si 1Ϫx Ge x . Based on the frequencies obtained from a simple vibrational model, the observed modes are assigned to specific combinations of the four Si and Ge neighbors to the carbon. The intensities of the modes indicate that the combination of the four neighbors deviates from a random distribution. Ab initio local-densityfunctional cluster theory has been applied to calculate the structure and the local mode frequencies of substitutional carbon with n Ge and 4Ϫn Si neighbors in a Si and a Ge cluster. The calculated frequencies are ϳ9% higher than those observed, but the ordering and the splitting of the mode frequencies agree with our assignments.

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“…This measurement can also be used to estimate the amount of ordered carbon pairs versus randomly distributed carbon atoms. A number of recent publications [5][6][7][8][9][10][11][12] were devoted to a study of the mechanism of the carbon distribution and ordering during Si 1−x−y Ge x C y growth and the microscopic strains in Si 1−x−y Ge x C y alloys with respect to the average lattice constant. There are a variety of interpretations in the literature on the origin of the Raman satellite Si-C peak at ϳ630 cm −1 .…”

Section: Introductionmentioning

confidence: 99%

Raman and Fourier transform infrared study of substitutional carbon incorporation in rapid thermal chemical vapor deposited Si1−x−yGexCy on (1 0 0) Si

Wasyluk

Perova

Meyer

2010

Journal of Applied Physics

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We report on a detailed study of the dependence of the vibrational modes in rapid thermal chemical vapor deposited Si1−x−yGexCy films on the substitutional carbon concentration. Si1−x−yGexCy films were investigated using Raman and infrared spectroscopy with x varying in the range of 10%–16% and y in the range of 0%–1.8%. The introduction of C into thin SiGe layers reduces the average lattice constant. It has been shown that the integrated infrared intensity of the Si–C peak and the ratio of both the Raman integrated and peak intensities of the Si–C peak (at ∼605 cm−1) to the Si–Si peak of SiGeC layer, increase linearly with C content and are independent of the Ge content. This leads to the conclusion that infrared absorption and Raman scattering data can be used to determine the fraction of substitutional carbon content in Si1−x−yGexCy layers with a Ge content of up to 16%. It is also shown that the intensity ratio of the carbon satellite peak to the local carbon mode increases linearly with C content up to a C level of 1.8%. This confirms a conclusion of an increase in the probability of creating third-nearest-neighbor pairs with increasing carbon content, as derived from theoretical calculations.

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Strain compensated heterostructures in the Si1−x−yGexCy ternary system

Cited by 46 publications

References 0 publications

Antibonding configurations of hydrogen in silicon-germanium alloys

Antibonding configurations of hydrogen in silicon-germanium alloys

Substitutional carbon inSi1−xGex

Raman and Fourier transform infrared study of substitutional carbon incorporation in rapid thermal chemical vapor deposited Si1−x−yGexCy on (1 0 0) Si

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