Annealing study of electron irradiation-induced defects in SiGe alloys

Goubet, J. J.; Stiévenard, D.

doi:10.1063/1.113217

Cited by 16 publications

(7 citation statements)

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“…This subject has already led to the collection of a fair amount of data for other point defects. [7][8][9][10][11][12] Our main motivation in the present study is to determine the energy level positions of both Fe i and Fe i -B s , as a function of the band gap variation due to a change in the Ge content. Then the impact of alloy disorder on the diffusivity is examined, as the disorder is expected to primarily affect the channels through which free iron is supposed to migrate.…”

Section: Introductionmentioning

confidence: 99%

Iron in relaxedSi1−xGexalloy: Band gap related levels, diffusion, and alloying effects

et al. 2002

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The microscopic behavior of iron in relaxed Si 1Ϫx Ge x alloy is addressed in the present work where various new aspects are highlighted. In p-type materials two types of defects involving iron may coexist under equilibrium; the isolated form, Fe i , and the iron-acceptor pair, Fe i -A s . The latter complex is favored over the former because it is thermodynamically more stable. In each case the iron atom stabilizes at the interstitial tetrahedral site. When boron is the acceptor impurity, both the isolated and the paired forms introduce donorlike levels, distant from each other by 0.28 eV. In the relaxed Si 1Ϫx Ge x bulk alloy, these levels are shown to remain separated by the same amount. However, they shift toward the valence band much faster than the shrinkage of the band gap when the Ge content is increased. The consequence is that the pair-related donor level merges with the valence band at a fairly low alloy composition (xу7%) while the iron donor level is predicted to disappear from the gap for xу25%. We also show that neither the entropy nor the enthalpy of migration of free iron, whose experimental determination requires one to take into account the abovementioned shift, are affected by alloying. Therefore, the fast diffusing character, attributed to iron in silicon, still holds in the alloy. The origin of spectral broadening, related to the chemical disorder, is discussed. Finally, the major technological implication emerging from our new findings is addressed. In particular, we show that both the gettering by segregation, routinely used in silicon, and the field-induced outdiffusion, established in n-type silicon ten years ago, are totally inefficient in the Si 1Ϫx Ge x alloy.

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Section: Introductionmentioning

confidence: 99%

Iron in relaxedSi1−xGexalloy: Band gap related levels, diffusion, and alloying effects

et al. 2002

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“…It should be noted that, unlike other studies in which the as-grown samples experienced proton irradiation [12][13][14][15] or ion implantation 20,21 in order to intentionally induce defects, the samples studied here were found to naturally form from point defects whose possible origin is similar to that seen in previous studies. [12][13][14][15]20,21 It was also found that two divacancy-related defects can be formed, regardless of which dopants were used. 9 In general, the mechanism for an E-center creation is explained by the fact that doping with P results in a contraction of the silicon lattice 24 due to the different atomic radii of P in a Si matrix.…”

Section: A Peak Identification and Suggested Mechanism Of Defect Formentioning

confidence: 50%

“…The dominant defects in the LT-MBE-grown samples are expected to be of intrinsic and/or dopant-related origin, because ͑1͒ the impurity concentration in the MBE-grown layers is low and ͑2͒ the defects found were annealed out without generating any other defects of comparable density. From the authors' previous study of LT-MBE-grown Si, 9 which compared results with defects in Si grown by chemical vapor deposition, 12,13 Czochralski, 12 MBE, 14 -19 and ion implantation, 20,21 the possible origin of the dominant defect, E1 and E11, was suggested as an E center (V -P) plus a singly negatively charged divacancy, V -V (0/Ϫ), complex. It is well known that the V -V (0/Ϫ) is located at E C Ϫ0.42 eV in Si 22,23 and strongly overlaps with the E center.…”

Section: A Peak Identification and Suggested Mechanism Of Defect Formentioning

confidence: 99%

Annealing of defect density and excess currents in Si-based tunnel diodes grown by low-temperature molecular-beam epitaxy

Chung

Jin

Pavlovicz

et al. 2004

Journal of Applied Physics

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Deep-level transient spectroscopy ͑DLTS͒ measurements were performed in order to investigate the effects of post-growth heat treatment on deep level defects in Si layers grown by low-temperature molecular-beam epitaxy ͑LT-MBE͒ at 320°C. In the LT-MBE as-grown samples, two dominant divacancy-related complex defects, of which the possible origins are suggested as P-V (E center)ϩV-V (0/Ϫ) and V-V (Ϫ2/Ϫ) and others, were observed in P-doped n layers. When the as-grown samples were annealed at 700, 800, and 900°C for 60 s by rapid thermal annealing, the total density of defects were decreased without generating other defects and most defects were annihilated at 900°C. This study also compared the DLTS trends with performance of Si-based resonant interband tunnel diodes ͑RITDs͒ in terms of peak current density, valley current density, and peak-to-valley current ratio, which are closely related to the deep-level defects. The active regions of the RITDs were grown at the same substrate growth temperature and annealed at similar temperatures used in this DLTS study.

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“…So far, many defect research groups have studied defects in silicon grown by chemical vapor deposition ͑CVD͒, 11,12 Czochralski ͑CZ͒ technique, 11 molecular-beam epitaxy, [13][14][15][16][17][18] or ion implantation. 19,20 But there remains some confusion in the literature about the role of dopants as a vacancy complex.…”

Section: Discussionmentioning

confidence: 99%

Growth temperature and dopant species effects on deep levels in Si grown by low temperature molecular beam epitaxy

Chung

Jin

Rice

et al. 2003

Journal of Applied Physics

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Deep-level transient spectroscopy measurements were performed in order to investigate the effects of substrate growth temperature and dopant species on deep levels in Si layers during low-temperature molecular beam epitaxial growth. The structures studied were n ϩ-p junctions using B doping for the p layer and p ϩ-n junctions using P doping for the n layer. While the density of hole traps H1 ͑0.38-0.41 eV͒ in the B-doped p layers showed a clear increase with decreasing growth temperature from 600 to 370°C, the electron trap density was relatively constant. Interestingly, the minority carrier electron traps E1 ͑0.42-0.45 eV͒ and E2 ͑0.257 eV͒, found in the B-doped p layers, are similar to the majority carrier electron traps E11 ͑0.48 eV͒ and E22 ͑0.269 eV͒ observed in P-doped n layers grown at 600°C. It is hypothesized that these dominating electron traps are associated with pure divacancy defects and are independent of the dopant species.

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Annealing study of electron irradiation-induced defects in SiGe alloys

Cited by 16 publications

References 0 publications

Iron in relaxedSi1−xGexalloy: Band gap related levels, diffusion, and alloying effects

Iron in relaxedSi1−xGexalloy: Band gap related levels, diffusion, and alloying effects

Annealing of defect density and excess currents in Si-based tunnel diodes grown by low-temperature molecular-beam epitaxy

Growth temperature and dopant species effects on deep levels in Si grown by low temperature molecular beam epitaxy

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