Low-defect metamorphic Si (Ge) epilayers on Si (001) with a buried template of nanocavities for multiple-junction solar cells

Raïssi, Mahfoudh; Regula, G.; Lazzari, J.–L.

doi:10.1016/j.solmat.2014.10.024

Cited by 6 publications

(3 citation statements)

References 40 publications

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“…To tackle this problem, different attempts involving the use of standard substrates have been proposed over the past decades to reduce the threading dislocation density (TDD) 14 – 20 , which is the main source of detrimental effects on the epilayer. Metamorphic growth involving several microns thick buffer layer either by compositional grading 16 – 18 or several high temperature annealing cycles 19 , has particularly achieved attractive results, and has succeeded in decreasing the TDD down to a threshold of 10 6 TD/cm². Other alternative methods consider patterned substrates as a mean to reduce the defects 21 – 23 .…”

Section: Introductionmentioning

confidence: 99%

Defect free strain relaxation of microcrystals on mesoporous patterned silicon

et al. 2022

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A perfectly compliant substrate would allow the monolithic integration of high-quality semiconductor materials such as Ge and III-V on Silicon (Si) substrate, enabling novel functionalities on the well-established low-cost Si technology platform. Here, we demonstrate a compliant Si substrate allowing defect-free epitaxial growth of lattice mismatched materials. The method is based on the deep patterning of the Si substrate to form micrometer-scale pillars and subsequent electrochemical porosification. The investigation of the epitaxial Ge crystalline quality by X-ray diffraction, transmission electron microscopy and etch-pits counting demonstrates the full elastic relaxation of defect-free microcrystals. The achievement of dislocation free heteroepitaxy relies on the interplay between elastic deformation of the porous micropillars, set under stress by the lattice mismatch between Ge and Si, and on the diffusion of Ge into the mesoporous patterned substrate attenuating the mismatch strain at the Ge/Si interface.

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Section: Introductionmentioning

confidence: 99%

Defect free strain relaxation of microcrystals on mesoporous patterned silicon

et al. 2022

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“…Devices like photodetectors 17,18 , multi-junction solar cells (MJSC) 19 , microprocessors 20 , modulators 21 , based on Ge-on-Si (001) technology must tackle these issues in order to achieve industry standards. To this end, several approaches have been proposed for reducing the TD density, such as compositional grading 22 , cyclic annealing 23,24 , epitaxial lateral overgrowth 25 , selective area depositions 26 , 3D heteroepitaxy 27 , virtual graded layers 28 , mesa structuring 29 , compliant substrates 30 , and ion-implanted substrates 31 . Despite their feasibility and originality, many of these techniques are limited to small-scale processes and require the use of expensive and complex processing technologies 32 .…”

Section: Introductionmentioning

confidence: 99%

Uprooting defects to enable high-performance III–V optoelectronic devices on silicon

Bioud¹,

Boucherif²,

Myronov³

et al. 2019

Nat Commun

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The monolithic integration of III-V compound semiconductor devices with silicon presents physical and technological challenges, linked to the creation of defects during the deposition process. Herein, a new defect elimination strategy in highly mismatched heteroepitaxy is demonstrated to achieve a ultra-low dislocation density, epi-ready Ge/Si virtual substrate on a wafer scale, using a highly scalable process. Dislocations are eliminated from the epilayer through dislocation-selective electrochemical deep etching followed by thermal annealing, which creates nanovoids that attract dislocations, facilitating their subsequent annihilation. The averaged dislocation density is reduced by over three orders of magnitude, from ~108 cm−2 to a lower-limit of ~104 cm−2 for 1.5 µm thick Ge layer. The optical properties indicate a strong enhancement of luminescence efficiency in GaAs grown on this virtual substrate. Collectively, this work demonstrates the promise for transfer of this technology to industrial-scale production of integrated photonic and optoelectronic devices on Si platforms in a cost-effective way.

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“…Nevertheless, porous substrates have valuable thin film applications, such as for photovoltaics, through their ability to create strain relaxed Si 1−x Ge x buffer layers on Si(001) with low threading dislocation density (TDD). Previously, such cavities have been created through the complex process of He + or H + ion implantation and annealing [14,15] rather than through the Kirkendall effect.…”

Section: Introductionmentioning

confidence: 99%

Kirkendall void formation in reverse step graded Si_1−xGe_x/Ge/Si(001) virtual substrates

Sivadasan

Rhead

Leadley

et al. 2018

Semicond. Sci. Technol.

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Formation of Kirkendall voids is demonstrated in the Ge underlayer of reverse step graded Si 1−x Ge x /Ge buffer layers grown on Si(001) using reduced pressure chemical vapour deposition (RP-CVD). This phenomenon is seen when the constant composition Si 1−x Ge x layer is grown at high temperatures and for x0.7. The density and size of the spherical voids can be tuned by changing Ge content in the Si 1−x Ge x and other growth parameters.

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Low-defect metamorphic Si (Ge) epilayers on Si (001) with a buried template of nanocavities for multiple-junction solar cells

Cited by 6 publications

References 40 publications

Defect free strain relaxation of microcrystals on mesoporous patterned silicon

Defect free strain relaxation of microcrystals on mesoporous patterned silicon

Uprooting defects to enable high-performance III–V optoelectronic devices on silicon

Kirkendall void formation in reverse step graded Si_1−xGe_x/Ge/Si(001) virtual substrates

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Low-defect metamorphic Si (Ge) epilayers on Si (001) with a buried template of nanocavities for multiple-junction solar cells

Cited by 6 publications

References 40 publications

Defect free strain relaxation of microcrystals on mesoporous patterned silicon

Defect free strain relaxation of microcrystals on mesoporous patterned silicon

Uprooting defects to enable high-performance III–V optoelectronic devices on silicon

Kirkendall void formation in reverse step graded Si1−xGex/Ge/Si(001) virtual substrates

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Kirkendall void formation in reverse step graded Si_1−xGe_x/Ge/Si(001) virtual substrates