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An Electrical Analysis of a Metal-Interlayer-Semiconductor Structure on High-Quality Si <sub/> 1? <i>x</i> </sub> Ge <sub/><i>x</i> </sub> Films for Non-Alloyed Ohmic Contact
摘要： In this paper, we have investigated the effect of a metal-interlayer-semiconductor (MIS) structure on intrinsic silicon-germanium (SiGe) film which is epitaxially grown by ultra-high vacuum chemical vapor deposition (UHV-CVD). Ultra-thin dielectric materials can alleviate Fermi-level pinning at the metal/Si1?xGex contact region by preventing penetration into the Si1?xGex of metal-induced gap states (MIGS) from the metal surface. The electrical properties which are the back-to-back current density and specific contact resistivity of the Ti/TiO2/Si1?xGex structure improve at the TiO2 interlayer thickness of 0.5 nm for all kinds of Si1?xGex film with various levels of germanium (Ge) concentration. The case of Si0.7Ge0.3 film, the specific contact resistivity of a Ti/TiO2(0.5 nm)/Si0.7Ge0.3 structure is reduced 80-fold compared to that of a Ti/Si0.7Ge0.3 structure. The effect of the MIS structure has been well demonstrated on Si1?xGex film, and as a result this structure is suggested as a novel source/drain (S/D) contact scheme for advanced Si1?xGex complementary metal-oxide-semiconductor (CMOS) technology.
关键词： Epitaxial Growth,Metal-Interlayer-Semiconductor,Source/Drain Contact,Silicon-Germanium,Fermi-Level Pinning,Specific Contact Resistivity
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Cancun (2018.8.29-2018.8.31)] 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Mid-Infrared Platforms for Chemical Sensing
摘要： For small gas systems using arrays of QCL sources, we have developed two distinct technology platforms for the fabrication of AWG, with more than 35 inputs in (i) the 3μm-8μm band for SiGe40 cores cladded with Si and (ii) the 8-12μm band for Ge cores cladded with SiGe20.
关键词： Germanium,AWG,MIR
更新于2025-09-23 15:22:29
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CoGe surface oxidation studied using X-ray photoelectron spectroscopy
摘要： Cobalt germanides have been widely studied as semiconductor contact materials, but recent theoretical studies suggest that they may also be excellent catalysts for methane steam reforming with stabilities and activities comparable to more expensive noble metal catalysts. We have sputter deposited CoGe alloy films and characterized their structure and morphology after post-deposition annealing in high vacuum up to 1000 °C. We used X-ray photoelectron spectroscopy to study the initial oxidation of amorphous and crystalline CoGe alloy surfaces under low pressures of O2 and H2O. The oxidation rate in O2 was found to be faster for an amorphous CoGe surface compared to a crystalline surface. We also found that there was little difference in the oxidation rate in H2O for either amorphous or crystalline surfaces. During O2 oxidation, the crystalline surface preferentially forms GeO and the amorphous surface preferentially forms GeO2. We have also observed preferential oxidation of Ge in the CoGe thin films. During temperature programmed desorption studies, we found that GeO desorption begins near 350 °C and that GeO2 decomposes to GeO and desorbs near 700 °C. More studies of CoGe catalysts are warranted, however GeO desorption may be a concern under reaction conditions when the film is subjected to an oxidizing environment.
关键词： Oxidation,Cobalt germanium,Temperature programmed desorption,Atomic force microscopy,X-ray photoelectron spectroscopy,X-ray diffraction
更新于2025-09-23 15:21:21
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Dispersion trimming for mid-infrared supercontinuum generation in a hybrid chalcogenide/silicon-germanium waveguide
摘要： We report a simple post-process technique that harnesses a hybrid chalcogenide/silicon-germanium system for the control of waveguide dispersion. By adding a chalcogenide top cladding to a SiGe/Si waveguide, we can substantially change the dispersive properties, which underpin the generation of a supercontinuum. In our particular example, we experimentally show that a shift from anomalous to normal dispersion takes place. We numerically study the dispersion dependence on the chalcogenide thickness and show how to use this additional degree of freedom to control the position of the zero dispersion wavelengths and hence the spectral span of the supercontinuum. Finally, we compare our approach with more traditional techniques that use geometry for dispersion tailoring.
关键词： mid-infrared,dispersion trimming,hybrid chalcogenide/silicon-germanium waveguide,supercontinuum generation
更新于2025-09-23 15:21:01
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27 GHz Silicon-contacted waveguide-coupled Ge/Si avalanche photodiode
摘要： We report a silicon-contacted Ge/Si avalanche photodiode with RF gain of 11 and a bandwidth of 27 GHz at -12 V operating at 1310 nm. The device is fabricated in an established Si photonics platform without additional process complexity and contacts only on Si. Wafer-scale performance data are presented confirming the reproducibility and the manufacturability of the device. Wide open eye diagrams are for 25, 40 and 50 Gbps data-rates. The demonstration of such avalanche photodiode shows great potential for improving optical link margins for optical transceivers operating at 400 Gb/s and beyond.
关键词： Silicon Photonics,Optical Interconnection,Germanium,Photodetectors
更新于2025-09-23 15:21:01
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On the Formation of Amorphous Ge Nanoclusters and Ge Nanocrystals in GeSixOy Films on Quartz Substrates by Furnace and Pulsed Laser Annealing
摘要： Nonstoichiometric GeO0.5[SiO2]0.5 and GeO0.5[SiO]0.5 germanosilicate glassy films are produced by the high-vacuum coevaporation of GeO2 and either SiO or SiO2 powders with deposition onto a cold fused silica substrate. Then the films are subjected to furnace or laser annealing (a XeCl laser, λ = 308 nm, pulse duration of 15 ns). The properties of the samples are studied by transmittance and reflectance spectroscopy, Raman spectroscopy, and photoluminescence spectroscopy. As shown by analysis of the Raman spectra, the GeO[SiO] film deposited at a substrate temperature of 100°C contains amorphous Ge clusters, whereas no signal from Ge–Ge bond vibrations is observed in the Raman spectra of the GeO[SiO2] film deposited at the same temperature. The optical absorption edge of the as-deposited GeO[SiO2] film corresponds to ~400 nm; at the same time, in the GeO[SiO] film, absorption is observed right up to the near-infrared region, which is apparently due to absorption in Ge clusters. Annealing induces a shift of the absorption edge to longer wavelengths. After annealing of the GeO[SiO2] film at 450°C, amorphous germanium clusters are detected in the film, and after annealing at 550°C as well as after pulsed laser annealing, germanium nanocrystals are detected. The crystallization of amorphous Ge nanoclusters in the GeO[SiO] film requires annealing at a temperature of 680°C. In this case, the size of Ge nanoclusters in this film are smaller than that in the GeO[SiO2] film. It is not possible to crystallize Ge clusters in the GeO[SiO] film. It seems obvious that the smaller the semiconductor nanoclusters in an insulating matrix, the more difficult it is to crystallize them. In the low-temperature photoluminescence spectra of the annealed films, signals caused by either defects or Ge clusters are detected.
关键词： crystallization,pulsed laser annealing,germanosilicate glasses,germanium nanoclusters
更新于2025-09-23 15:21:01
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A Bean-Like Formation of Germanium Nanoparticles Inside CNTs by the Subsequent Operation of Colloidal Synthesis and Catalytic Chemical Vapor Deposition Methods
摘要： The first attempts of implanting Ge nanoparticles (Ge NPs) inside iron filled CNTs (IF-CNTs) by a subsequent use of the bench top colloidal synthesis and chemical vapor deposition (CVD) approach is shown. Ge NPs are colloidally synthesized (with a 3.8 ± 0.6 nm in size) before the deposition. The hybrid Ge NPs/IF-CNTs structure and morphology are characterized using high-resolution transmission electron microscopy, scanning electron microscopy, selective area electron diffraction, and X-ray diffraction studies. After the deposition, Ge NPs appear to be grown in size and to be sprinkled almost homogeneously into the IF-CNTs similar to a bean-like deposition. CNTs diameter is also identified to be enlarged drastically when using Ge NPs as a catalyst in CVD compared to the CNTs formation without Ge NPs. In addition, micro-length rectangular Ge μPs are also found outside the nanotube core. Rietveld analysis shows the presence of γ-Fe (Fm-3m), ferromagnetic α-Fe (Im-3m), Fe3C, Ge (Fd-3m), and multiwall CNTs. The results indicate that Ge NPs and IF-CNTs demonstrate cocatalytic activity in increasing the respective sizes, which are dramatically larger than those obtained by the conventional approaches.
关键词： ferromagnetism,germanium,nanoparticles,colloidal,chemical vapor deposition,CNTs
更新于2025-09-23 15:21:01
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Analysis of High-Purity Germanium Dioxide by Inductively Coupled Plasma Atomic Emission Spectrometry with Reaction Distillation of the Matrix
摘要： A combined method of analysis of high-purity germanium dioxide by atomic emission spectrometry with matrix preseparation and trace element preconcentration was developed. The matrix was separated in an autoclave of a MARS 5 microwave system without the contact of samples with an acid solution. The method allows the determination of the following 50 analytes with the limits of detection 10–8–10–5 wt %: Ag, Al, As, Au, B, Ba, Be, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Gd, Hf, Hg, Ho, In, La, Li, Lu, Mg, Mn, Na, Nb, Nd, Ni, P, Pb, Pr, Re, Sb, Sc, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tm, W, Y, Yb, Zn, and Zr.
关键词： high-purity germanium dioxide,matrix separation,limits of detection,atomic emission spectrometry,inductively coupled plasma,multielement analysis
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE 7th International Conference on Photonics (ICP) - Langkawi, Malaysia (2018.4.9-2018.4.11)] 2018 IEEE 7th International Conference on Photonics (ICP) - Modal Properties of a Varied High Indexed Large Core 4-Mode Photonic Crystal Fiber
摘要： A varied high indexed, large core 4-mode photonic crystal fiber is proposed. Consequences of variation in the refractive index of the materials used in the rings have been analyzed through the far field distribution and phase of each mode. The influence of different, air hole diameters and distances between the holes of the fiber is studied.
关键词： refractive index,germanium doped fiber,photonic crystal fiber,design
更新于2025-09-23 15:21:01
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Spin pumping and laser modulated inverse spin Hall effect in yttrium iron garnet/germanium heterojunctions
摘要： In this work, undoped semiconductors, germanium (Ge) and germanium tin (GeSn), were grown on ferrimagnetic insulator yttrium iron garnet (YIG) thin ?lms using ultra-high vacuum molecular beam epitaxy. The crystallinity of the structure was determined from x-ray diffraction and high-resolution transmission electron microscopy combined with energy dispersive x-ray spectroscopy. Both spin pumping and inverse spin Hall effects (ISHEs) of YIG/Ge and YIG/GeSn heterojunctions have been investigated with the help of broadband ferromagnetic resonance (FMR). We observe that the spin mixing conductances of YIG/Ge (60 nm) and YIG/GeSn (60 nm) are 5.4 (cid:2) 1018 m(cid:3)2 and 7.2 (cid:2) 1018 m(cid:3)2, respectively, responsible for giant spin current injection. Furthermore, it is found that spin pumping injects giant spin current from ferrimagnetic YIG into the Ge semiconductor. The infrared laser modulated ISHE was examined using heavy metal platinum as a spin current collector. Also, it has been noted that the variation in the power of laser irradiation signi?cantly changed the ISHE voltage of YIG/Ge/Pt spin junctions, saturated magnetization, FMR linewidth, and Gilbert damping parameter of YIG, which could be attributed to the laser-induced thermal effect. The outcomes from this study are promising for the development of Ge-based spintronic and magnonic devices.
关键词： germanium tin,magnonics,germanium,spin pumping,inverse spin Hall effect,yttrium iron garnet,spintronics
更新于2025-09-23 15:19:57