Solid-phase epitaxial regrowth and dopant activation of P-implanted metastable pseudomorphic Ge0.12Si0.88 on Si(100)

Lie, Donald Y. C.; Theodore, N. David; Song, Jung-Hoon; Nicolet, M.‐A.

doi:10.1063/1.359261

Cited by 15 publications

(22 citation statements)

References 44 publications

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“…Studies of dopant incorporation and its electrical activation during solid phase regrowth of the SiGe layers have been reported in the cases of Sb and P impurities implanted into the SiGe layers. 12,13 Boron doping of SiGe layers using this growth method has also been reported recently. 14 The active impurity concentrations achieved were of around 3ϫ10 20 cm Ϫ3 , well above the equilibrium solid solubility of B in pure Si.…”

Section: Introductionmentioning

confidence: 89%

Strain and defects depth distributions in undoped and boron-doped Si1−xGex layers grown by solid phase epitaxy

Rodrı́guez

Kling

et al. 1997

Journal of Applied Physics

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Strain-conserving doping of a pseudomorphic metastable Ge0.06Si0.94 layer on Si(100) by low-dose BF2 + implantation A detailed characterization of undoped and heavily boron-doped Si 1Ϫx Ge x layers with xϭ0.21, 0.26, and 0.34 grown on ͑001͒ Si wafers by solid phase epitaxy is presented. The starting material for solid phase epitaxial growth was prepared by amorphization of epitaxial SiGe-Si heterostructures by ion implantation. In order to obtain doped layers, boron was also implanted into some of the amorphous samples. After regrowth, the strain depth distributions of the SiGe layers were measured using axial channeling angular scans and the defect distributions were observed by high-resolution electron microscopy. A defect-free region ranging from 0 nm ͑undoped layer of x ϭ0.34) to 30 nm ͑doped layer of xϭ0.21) in thickness was observed next to the layer-substrate interface. In the upper region of the layers, strain-relieving defects, identified as planar faults, were observed. Some isolated defects were also present at the layer-substrate interfaces of most of the samples. The measured strain depth profiles show that ͑i͒ the defect-free regions are not always fully strained; the defects located at the interfaces being responsible for this partial relaxation; ͑ii͒ the strain is almost constant throughout the defect-free layers because it cannot be relieved due to the absence of defects; and ͑iii͒ the strain progressively decreases towards the sample surfaces in the region of the layer where the strain-relieving defects are located. Comparison between the undoped and boron-doped layers show the consequences of the strain compensation effect due to the incorporation of boron atoms into the lattice. The defect-free regions of the doped layers are thicker and closer to coherency than those in the undoped layers of the same composition and the defect density in the upper region of the layers is significantly reduced. As a result of the strain compensation effect, a 30-nm-thick heavily doped layer with xϭ0.21 is found to be defect free and fully strained throughout its whole thickness although the corresponding undoped layer was partially relaxed and showed strain-relieving defects.

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Section: Introductionmentioning

confidence: 89%

Strain and defects depth distributions in undoped and boron-doped Si1−xGex layers grown by solid phase epitaxy

Rodrı́guez

Kling

et al. 1997

Journal of Applied Physics

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“…24,25,107,108,114 The channeling minimum yields for these regrown GeSi are ~6-8%, which values are considerably higher than those of the as-deposited Ge x Si 1-x (~3-4%). 25,98 However, it should be pointed out that in the case of arsenic-implanted Si, the regrowth velocity is a complicated function of the arsenic ion dose, where velocity enhancement as well as retardation, precipitation of dopants and dopant-induced random nucleation and growth have all been observed. The reason for this difference between regrown Si and GeSi will be discussed later in detail in the General Discussion of Solid-Phase Epitaxy of GeSi.…”

Section: Degraded Crystallinity For Metastable Gesimentioning

confidence: 82%

“…25,94,95,98 The channeling spectra of amorphized Si after solid-phase epitaxy are indistinguishable from that of a virgin sample; however, the spectra for amorphized GeSi after solid-phase epitaxy show a step-like increase in yields at and below ~1.1 MeV. The peak concentration of As ions is roughly 3 × 10 20 /cm 3 , as estimated from both the backscattering spectra and TRIM simulations.…”

Section: Degraded Crystallinity For Metastable Gesimentioning

confidence: 82%

“…For all as-implanted samples, the backscattering yields that correspond to the nearsurface portions of the layers reach the levels of their random spectra, which indicates that the top ~125 nm of these 145 nm thick samples are amorphized after implantation. [22][23][24][25]55,59,[107][108][109][110] Olson and Roth have showed that the solid-phase epitaxy velocity of undoped Si(100) at 500°C is ~0.57 nm/min, and Paine et al have reported that this velocity at 500°C for undoped x = 0.054 is ~0.20 nm/ min, and for undoped x = 0.17 is ~0.24 nm/min. The amorphous/ crystalline fronts in Figs.…”

Section: Degraded Crystallinity For Metastable Gesimentioning

confidence: 99%

“…11 Implantation creates damage and additional strain in intrinsically strained GeSi, and post-implantation annealing is required to remove them. [21][22][23][24][25] It is thus important to perform a systematic study on ion-implanted GeSi to understand how to successfully apply ion implantation technology to fabricate reliable Si/GeSi devices. The presence of intrinsic pseudomorphic strain changes the band structure of Si/GeSi and can enhance the mobility of carriers.…”

Section: Introductionmentioning

confidence: 99%

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Doping and processing epitaxial GexSi1−x films on Si(100) by ion implantation for Si-based heterojunction devices applications

Lie

1998

Journal of Elec Materi

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The question of whether one can effectively dope or process epitaxial Si(100)/ GeSi heterostructures by ion implantation for the fabrication of Si-based heterojunction devices is experimentally investigated. Results that cover several different ion species (B, C, Si, P, Ge, As, BF 2 , and Sb), doses (10 13 to 10 16 /cm 2 ), implantation temperatures (room temperature to 150°C), as well as annealing techniques (steady-state and rapid thermal annealing) are included in this minireview, and the data are compared with those available in the literature whenever possible. Implantation-induced damage and strain and their annealing behavior for both strained and relaxed GeSi are measured and contrasted with those in Si and Ge. The damage and strain generated in pseudomorphic GeSi by room-temperature implantation are considerably higher than the values interpolated from those of Si and Ge. Implantation at slightly elevated substrate temperatures (e.g., 100°C) can very effectively suppress the implantation-induced damage and strain in GeSi. The fractions of electrically active dopants in both Si and GeSi are measured and compared for several doses and under various annealing conditions. Solid-phase epitaxial regrowth of GeSi amorphized by implantation has also been studied and compared with regrowth in Si and Ge. For the case of metastable epi-GeSi amorphized by implantation, the pseudomorphic strain in the regrown GeSi is always lost and the layer contains a high density of defects, which is very different from the clean regrowth of Si(100). Solid-phase epitaxy, however, facilitates the activation of dopants in both GeSi and Si, irrespective of the annealing techniques used. For metastable GeSi films that are not amorphized by implantation, rapid thermal annealing is shown to outperform steady-state annealing for the preservation of pseudomorphic strain and the activation of dopants. In general, defects generated by ion implantation can enhance the strain relaxation process of strained GeSi during post-implantation annealing. The processing window that is optimized for ionimplanted Si, therefore, has to be modified considerably for ion-implanted GeSi. However, with these modifications, the mature ion implantation technology can be used to effectively dope and process Si/GeSi heterostructures for device applications. Possible impacts of implantation-induced damage on the reliability of Si/GeSi heterojunction devices are briefly discussed.

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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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Solid-phase epitaxial regrowth and dopant activation of P-implanted metastable pseudomorphic Ge0.12Si0.88 on Si(100)

Cited by 15 publications

References 44 publications

Strain and defects depth distributions in undoped and boron-doped Si1−xGex layers grown by solid phase epitaxy

Strain and defects depth distributions in undoped and boron-doped Si1−xGex layers grown by solid phase epitaxy

Doping and processing epitaxial GexSi1−x films on Si(100) by ion implantation for Si-based heterojunction devices applications

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

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