Damage and strain in epitaxial Ge<i>x</i>Si1−<i>x</i> films irradiated with Si

Lie, Donald Y. C.; Vantomme, André; Eisen, F. H.; Vreeland, T.; Nicolet, M.‐A.; Carns, T. K.; Arbet-Engels, V.; Wang, K. L.

doi:10.1063/1.355219

Cited by 56 publications

(29 citation statements)

References 21 publications

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“…This fact strongly suggests that the Er ions implantation with a given fluence produces the same additional strain regardless the concentration of Ge. This result is consistent with that reported earlier in Ref [24] which state that the initially uniform strain of the Si 1-x Ge x films does not affect the implantation-induced strain generated by Si irradiation.…”

Section: Resultssupporting

confidence: 83%

Defect production in strained p-type Si1−xGex by Er implantation

Mamor

Pipeleers

Auret

et al. 2011

Journal of Applied Physics

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Strained p-Si 1-x Ge x (x = 5.3%, 10.2% and 15.4%) was irradiated at room temperature with 160 keV 166 Er 2+ ions to a fluence of 1×10 10 or 3×10 13 Er/cm 2 . The defects induced by ion implantation were investigated experimentally using high-resolution X-ray diffraction, Rutherford backscattering and channeling spectroscopy and deep level transient spectroscopy. X-ray diffraction indicates that the damage induced by Er implantation produces a slight perpendicular expansion of the SiGe lattice. For all compositions, channeling measurements reveal that Er implantation in pSi 1-x Ge x to a fluence of 3×10 13 Er/cm 2 induces an amorphous region below the Si 1-x Ge x surface.Annealing at 850°C for 30 s, results in a reduction in damage density, a relaxation of the implantation-induced perpendicular expansion of the SiGe lattice in the implanted region, while a more pronounced relaxation of the compressive strain SiGe is observed for higher Ge content (x = 0.10 and 0.15). On the other hand, for the annealed SiGe samples that were implanted with Er at the fluence of 10 10 Er/cm 2 , the compressive strain in the SiGe layer is nearly completely retained. Deep level transient spectroscopy studies indicate that two prominent defects with discrete energy levels above the valence band are introduced during Er implantation. Their activation energy was found to decrease with increasing Ge-content. However, the large local strain induced by high fluence Er implantation reduces the activation energy by 40 meV with respect to the low fluence Er implanted p-Si 1-x Ge x . This shift (40 meV) in the activation energy remains constant regardless of the Ge content, suggesting that the Si 1-x Ge x layers remained fully strained after Er implantation. The observed defects are further compared to those introduced by alpha particle irradiation and electron beam metal deposition. The results indicate that defects introduced by Er implantation have similar electronic properties as those of defects detected after electron beam deposition and alpha particle irradiation. Therefore, it is concluded that these defects are due to the Er implantation-induced damage and not to the Er species specifically.Electronic mail: mamor@squ.edu.om 2

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Section: Resultssupporting

confidence: 83%

Defect production in strained p-type Si1−xGex by Er implantation

Mamor

Pipeleers

Auret

et al. 2011

Journal of Applied Physics

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“…Double-crystal rocking curves of (400) symmetrical diffraction taken with Cu-Kc~ radiation (X=1.54 ,~) for a metastable pseudomorphic Geo.osSio92 layer grown on Si(100) implanted at room temperature with 1• 10t3/cm 2 90keV BF2 ions: (a) after 30 min annealing in vacuum from 500 to 900"C, and (b) after short 40 s annealing in nitrogen ambient at 800, 850, and 900~ The positions of diffraction peak for a pseudomorphic and a fully relaxed epitaxial Geo.osSio. dicating that the implantation introduced additional compressive perpendicular strain in the film [14]. This additional strain disappears after annealing at 500~ The spectra of samples annealed between 500-700~ have same epilayer peak intensity and the peak position as those of the as-grown (virgin) samples (-0.225~ Unlike the results obtained from ion channeling measurements, the rocking curve for the sample after annealing at 800"C shows clear signs of strain relaxation.…”

Section: Resultscontrasting

confidence: 53%

Strain conservation in implantation-doped GeSi layers on Si(100)

Nicolet

1997

Metals and Materials

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Metastable pseudomorphic GeSi layers grown by chemical vapor deposition or by molecular beam epitaxy on Si(100) substrates were implanted at room temperature. The implantations were performed with 90 keV As ions to a dose of 1 • 10 ~3 cm -2 for Ge.0~Si~.,~2 layers and 70 keV BF2 ~ ions to a dose of 3• 10 ~ cm 2 for Ge..,~Sio~4 layers. The samples were subsequently annealed for short 10-40 s durations in a lamp furnace with a nitrogen ambient, or for a long 30 min period in a vacuum tube furnace. For Geo0,Si~,,~2 samples annealed for a 30 min-long duration at 700~ the dopant activation can only reach 50% without introducing significant strain relaxation, whereas samples annealed for short 40 s periods (at 850"C) can achieve more than 90% activation without a loss of strain. For Ge0.,Sio,4 samples annealed for either 40 s or 30 min at 800~ full electrical activation of the boron is exhibited in the GeSi epilayer without losing their strain. However, when annealed at 900~ the strain in both implanted and unimplanted layers is partly relaxed after 30 rain, whereas it is not visibly relaxed after 40 s.

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“…The higher nuclear energy deposition reported for Ge in comparison to Si was attributed to the higher mass and increased stopping power in Ge. 8 Amorphization in Ge occurs at lower fluences than those required for Si, 6,9 and even a 5 Â 10 13 cm À2 Ge self-implantation is able to amorphize. When heavy ions are implanted at high fluences, a severe swelling of amorphous Ge has been observed, the amorphous layer presenting a honeycomb-like structure formed by large cavities separated by thin walls.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulations of damage production by thermal spikes in Ge

López¹,

Pelaz²,

Santos³

et al. 2012

Journal of Applied Physics

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Molecular dynamics simulation techniques are used to analyze damage production in Ge by the thermal spike process and to compare the results to those obtained for Si. As simulation results are sensitive to the choice of the inter-atomic potential, several potentials are compared in terms of material properties relevant for damage generation, and the most suitable potentials for this kind of analysis are identified. A simplified simulation scheme is used to characterize, in a controlled way, the damage generation through the local melting of regions in which energy is deposited. Our results show the outstanding role of thermal spikes in Ge, since the lower melting temperature and thermal conductivity of Ge make this process much more efficient in terms of damage generation than in Si. The study is extended to the modeling of full implant cascades, in which both collision events and thermal spikes coexist. Our simulations reveal the existence of bigger damaged or amorphous regions in Ge than in Si, which may be formed by the melting and successive quenching induced by thermal spikes. In the particular case of heavy ion implantation, defect structures in Ge are not only bigger, but they also present a larger net content in vacancies than in Si, which may act as precursors for the growth of voids and the subsequent formation of honeycomb-like structures.

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Damage and strain in epitaxial GexSi1−x films irradiated with Si

Cited by 56 publications

References 21 publications

Defect production in strained p-type Si1−xGex by Er implantation

Defect production in strained p-type Si1−xGex by Er implantation

Strain conservation in implantation-doped GeSi layers on Si(100)

Molecular dynamics simulations of damage production by thermal spikes in Ge

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