Wafer scale epitaxial germanium on silicon (0 0 1) using pulsed laser annealing

Kumari, Khushboo; Vura, Sandeep; Raghavan, Srinivasan; Avasthi, Sushobhan

doi:10.1016/j.matlet.2020.129208

Cited by 5 publications

(5 citation statements)

References 14 publications

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“…However, an uneven surface was produced if sintered with higher UV laser power than required due to high Ge NPs ablation, which is shown in figure 2(f). Laser power is maximum at the center of the Gaussian beam, which leads to a non-uniform ablation [7]. Laser ablation generally produces a rough surface due to non-uniform removal of molten material, the formation of laser-induced ripples, the overlap between laser spots along the line and between the lines.…”

Section: Ls Impact On Surface Morphologymentioning

confidence: 99%

“…Furthermore, mobility can be increased by incorporating tin (Sn) in the film [6]. However, there is a huge fabrication challenge of integrating Ge with Si due to a large lattice mismatch of 4.2% [7].…”

Section: Introductionmentioning

confidence: 99%

“…The LS of micro/nanoparticles (NPs) provides a continuous film and simultaneous crystallization of thin film. The LS method of crystallizing films is a cost-effective, fast, scalable, and low thermal-budget process than furnace-based processes [7]. However, most of the published LS-based scientific reports used complex deposition methods such as CVD [7], molecular beam epitaxy (MBE) [4], and plasma sputtering [5].…”

Section: Introductionmentioning

confidence: 99%

“…The LS method of crystallizing films is a cost-effective, fast, scalable, and low thermal-budget process than furnace-based processes [7]. However, most of the published LS-based scientific reports used complex deposition methods such as CVD [7], molecular beam epitaxy (MBE) [4], and plasma sputtering [5]. Also, the thickness of the film is limited to a maximum of 1 µm.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Synthesis, structural, optical, and electrical properties of continuous wave and pulse laser sintered semiconductor Ge films

Islam¹,

Gupta²

2022

Semicond. Sci. Technol.

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The crystallization process of Ge films by a continuous wave (CW) and a pulsed laser is very effective for producing smooth, homogeneous, and crack-free polycrystalline films to use in transistors, photodetectors, and photovoltaic applications. However, little progress has been made to directly crystallize Ge films based on micro/nanoparticles (NPs) using the laser sintering (LS) process. In this paper, a simultaneous LS and crystallization process of Ge micro/nanoparticles to develop thick polycrystalline films on silicon substrates is demonstrated. Silicon substrates with a SiO2 insulating layer on top were considered for compatibility with complementary metal-oxide-semiconductor (CMOS) technology. The LS process was applied to solution deposited micro/nanoparticles, 5 µm thick Ge films using both CW mode (infrared (IR) laser of wavelength 1070 nm) and pulse mode (UV laser of wavelength 355 nm) laser. After the LS process, around 2-2.5 µm thick film of polycrystalline Ge (pc-Ge) was achieved with optical and electrical properties comparable to traditionally developed chemical vapor deposited films. The crystallinity of the pc-Ge films was evaluated by Raman spectroscopy and XRD diffraction. The laser-sintered films exhibited a Raman peak at 300 cm−1 and XRD 2θ peak at 27.35, which indicated the poly-crystalline structure. The fabricated film showed high hole mobility of 203 cm2/V.s, without any doping and film electrical resistivity value of 6.24x105 Ω-cm. The developed LS process allows the quick deposition of polycrystalline thick films, removing surface porosity and voids, increasing films adhesion with the substrate, and faster thermal annealing.

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Section: Ls Impact On Surface Morphologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis, structural, optical, and electrical properties of continuous wave and pulse laser sintered semiconductor Ge films

Islam¹,

Gupta²

2022

Semicond. Sci. Technol.

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“…The same concept has been applied to epitaxial Ge on Si to reduce the surface roughness [14]. Laser annealing is another method that is found to improve the crystallinity of epitaxial Ge on Si [15], [16] and reduce the surface roughness [17]. Due to the strong absorption of short wavelength light in Ge, the laser annealing technique can be tuned to target local, near-surface recrystallization with different depths.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Ge-on-Si waveguide propagation loss by laser and hydrogen annealing

Lim

Fong

Ang

et al. 2023

Integrated Optics: Devices, Materials, and Technologies XXVII

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Germanium-on-Silicon (Ge-on-Si) platform has been demonstrated as an excellent candidate for mid-infrared photonics applications, including on-chip mid-infrared spectroscopy and biochemical sensing. However, this platform is often saddled by high propagation loss due to a combination of threading dislocation defects at the Ge/Si interface, absorption in the silicon for λ < 8 μm, and surface scattering due to sidewall roughness. This work investigates the effects on loss reduction through different annealing techniques on Ge-on-Si waveguides fabricated using CMOS-compatible processes. We explore the use of local laser annealing at waveguide sidewalls, whereby the fluence was varied. A non-local annealing technique in hydrogen ambient was also employed as comparison. The propagation losses for wavelengths, ranging from λ = 5 μm to λ = 11 μm, were systematically characterized by fabricating waveguide and grating coupler structures on the same chip. Cutback measurements were performed by varying the waveguide length (of the same width) from L = 1 mm to L = 4 mm. Both hydrogen and laser annealing experiments show marked reduction in the propagation loss, by up to 27% and 46% respectively. This finding paves the way for post-processing techniques to reduce propagation loss in Ge-on-Si platform, which will enable various on-chip mid-IR applications in the future.

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Polycrystalline GeSn thin films fabricated by simultaneous laser sintering and recrystallization

Islam

Gupta

2023

J Mater Sci: Mater Electron

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Wafer scale epitaxial germanium on silicon (0 0 1) using pulsed laser annealing

Cited by 5 publications

References 14 publications

Synthesis, structural, optical, and electrical properties of continuous wave and pulse laser sintered semiconductor Ge films

Synthesis, structural, optical, and electrical properties of continuous wave and pulse laser sintered semiconductor Ge films

Reduction of Ge-on-Si waveguide propagation loss by laser and hydrogen annealing

Polycrystalline GeSn thin films fabricated by simultaneous laser sintering and recrystallization

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