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Investigates the complex refractive index of silicon germanide layers on silicon substrates. Use of in situ ellipsometry during reactive ion etching; Determination of the germanium concentration; Inversion of the ellipsometry equations.

Examines luminescence originating from within silicon/silicon germanide multiple heterostructures. Manifestation of an induced-low temperature photoluminescence; Production of alloy-broadened spectra; Discussion on the epilayer-induced intrinsic radiative recombination.

Studies the resistivity of copper germanide thin films formed at low temperatures. Formation of a monoclinic crystal structure; Reduction of device dimensions.

Electrical properties have been examined for single Si/Si0.8Ge0.2 p-type modulation-doped heterostructures which have been grown by molecular beam epitaxy. It is shown that the two-dimensional hole gas in a normal modulation-doped heterostructure (doped layer on the surface side) has a higher mobility than in an inverted structure (doped layer on the substrate side). Secondary-ion mass spectrometry analysis indicates that the lower mobility in the inverted structure is due to surface segregation of boron. Hole mobilities as high as 6000 cm2/V s at 2 K and 3800 cm2/V s at 6 K have been obtained which are the highest values reported so far for Si/SiGe heterostructures. [ABSTRACT FROM AUTHOR]

Localized epitaxial Co5Ge7 and CoGe2 have been grown in cobalt thin films on (111)Ge in the solid phase epitaxy regime. The orientation relationships between epitaxial germanides and the substrates as well as the configuration of the interfacial dislocations were analyzed by transmission electron microscopy (TEM) in detail. Surface morphology was examined by scanning electron microscopy. The results obtained from Read camera glancing angle x-ray diffraction and Rutherford backscattering channeling analysis were found to corroborate with those from TEM examinations. [ABSTRACT FROM AUTHOR]

Examines the influence of electron beam irradiation on the morphology of plasma deposited amorphous hydrogenated carbon-germanium films produced from tetramethylgermanium. Insensitivity of the material to the process; Occurrence of a crystalline phase in the semiconductor; Agglomeration of germanium nanocrystals in globules of 50-500 nanometer in diameter.

Examines the influence of lateral forces on the relaxation and surface topography of linearly graded Si[sub 1-x]Ge[sub x] heterostructures. Changes on the relaxation mechanism on the Si mesa pillars for deposition of 10 micrometer and below; Creation of a cross-hatch free surface; Orthogonal misfit interactions for dimensions above 10 micrometer.

Presents a method for preparing wafer sized silicon germanide quantum dots on an ordered mesoporous silica coated silicon. Use of x-ray diffraction to verify quantum dot formation; Light emission capacity of the material in initial low temperature photoluminescence measurements; Effectiveness of the technique for quantum dot array production.

Examines a model of the ordering mechanism in silicon germanide films with reconstructed surface. Implication for the occurrence of ordered structure types; Investigation on the stability of the structures by strain energy calculations; Discussion on the atomic exchange process forming the ordered structure at reconstructed surfaces.

Proposes a model to explain hydrogen desorption kinetics in silicon germanide (Ge) alloys. Inclusion of hydrogen diffusion constant and frequency factors as model parameters; Occurrence of hydrogen desorption in Ge dimers; Effect of diffusion-limited desorption of hydrogen on desorption kinetics.

Examines the strain relaxation and defect formation during surface roughening of Si[sub 1-x]Ge[sub x] films grown epitaxially on (100)silicon substrates. Use of controlled annealing experiments; Thickness and germanium (Ge) content of films; Study on surface grooves aligned along <110> directions.

Details the optical transition of silicon germanide alloys into uniform quantum dots. Use of molecular beam epitaxy in the study; Observation on the photoluminescence from the quantum dots; Comparison to the photoluminescence of silicon germanide/silicon quantum well.

Examines the thickness of a Si[sub 0.6]Ge[sub 0.4] layer deposited on patterned silicon substrate containing mesas of width ranging from two to 200 micrometer. Use of Raman spectra at various sample points; Consideration of variation in layer thickness as a growth rate consequence; Measurement of layer stress by Raman shift.

Examines the conversion of step configuration induced by strain in silicon germanide layers embedded on vicinal silicon(001) surfaces. Application of reflection high energy electron diffraction to the conversion processes; Effect of germanium mole fraction on conversion process; Use of optical fiber for identifying the intensity of half order beams.

Examines the electron irradiation-induced defects in silicon germanide alloys. Location of associated energy levels; Determination of capture cross sections; Proposal of identifying defects as silicon divacancy and the E center.

Examines effective masses in doped silicon (Si)/silicon germanide (SiGe) hole quantum wells. Formation of the two-dimensional hole gas at SiGe/Si heterointerface; Dependence of hole effective mass on Ge concentration; Calculations of nonparabolicity in SiGe.

Measures the photoluminescence (PL) of strained silicon germanide (SiGe) alloy quantum wells (QW) on Si. Passivation of Si surface to increase SiGe QW PL; Control of surface recombination on SiGe PL decay; Achievement of SiGe PL from 77 to 250 Kelvin.

Presents a thermally stable, low resistance ohmic contact to n-type gallium arsenide using Cu[sub 3]Ge. Electrical stability of the contact during annealing; Characteristic of the material at varied germanium concentration; Comparison of transconductance to devices with germanium/palladium and AuGeNi contacts.

Examines the fabrication of silicon germanide (SiGe) disordered superlattices (d-SL) by solid source molecular beam epitaxy. Comparison of photoluminescence (PL) properties between d-SL and ordered SL; Observation of intense PL peak in d-SL; Enhancement of the luminescence process in SiGe strained layer on carrier confinement.

Examines the production of very slow dislocation, relaxed silicon germanide (SiGe) heterostructures. Formation of SiGe layer on silicon (Si) substrate; Equalization of the strain between Si and SiGe layer; Benefits of S-on-insulator substrate for parasitics.

Investigates the fabrication of silicon germanide (SiGe) quantum wire structures by gas-source selective epitaxial growth (SEG) technique. Properties of Si-based heterostructures; Ways to clarify the specific properties brought by wire geometry; Importance of SEG in the formation of SiGe layer with reduced dimension.

Examines the fabrication of wires and dots with silicon germanide (SiGe) quantum wells using molecular beam epitaxy. Observation of excitonic luminescence from SiGe quantum wells; Embedment of SiGe quantum wells in Si; Comparison of the nonradiative recombination rates between the experimental data and differential epitaxy.

Examines the oxidation of silicon germanide at low temperatures by electron cyclotron resonance (ECR) plasma. Electrical properties of the materials; Indication of the high frequency and quasistatic capacitance-voltage of the alloy; Comparison of characteristics with ECR grown metal-oxide semiconductor capacitors on silicon with an aluminum gate.

Examines the optimization of germanium/carbon (Ge/C) ratio compensation of misfit strain in solid phase epitaxial (SPE) growth of silicon germanide (SiGe) layers. Reduction of misfit dislocations and stacking faults in SPE grown SiGe alloy layers; Existence of strain compensation effect in Ge/C ratio; Discussion on the spatial distributions of Ge and C.

Presents the femtosecond ellipsometric study of nonequilibrium carrier dynamics in Si[sub 1-x]Ge[sub x] alloys. Growth of alloy films on silicon substrate by molecular beam epitaxy; Effect of band-gap renormalization on the bound electron component of the dielectric function; Relationship between free carrier density and interband absorption.

Examines the electron transport properties of silicon layer on silicon germanide substrate (SiGe). Use of band-gap engineering in Si/SiGe heterostructures; Achievement of high mobility in modulation-doped Si/SiGe; Action of SiGe substrate in electron gas.

Examines the kinetics of hydrogen desorption in surface-limited thin film growth of silicon germanide alloys from binary mixtures of disilane and digermane. Use of surface differential reflectance; Components consisting the hydrogen desorption process from the alloy surface; Measurement of the desorption rates of the components.

Measures the crystallographic tilt in relaxed Si[sub 0.7]Ge[sub 0.3] thin films grown on vicinal (001) silicon substrates. Relationship of the tilt angle orientation with the miscut; Significance of intermediate graded layers in the angle size; Influence of the miscut on activation energy of nucleation and glide force applied on dislocations.

Investigates the correlation between damage saturation and temperature during (Si) ion implantation of silicon germanide alloys. Effect of lattice defects on Si damage saturation; Nucleation of damage saturation during ion irradiation; Occurrence of damage saturation by nucleation.

Examines the distribution of germanium in silicon germanide (SiGe) structures after oxygen implantation. Embedment of SiGe layers in silicon; Distribution of Ge in the implanted oxide layer; Effect of Ge diffusion on Si.

Analyzes the elastic misfit stress relaxation in heteroepitaxial silicon germanide (SiGe)/Si mesa structures. Calculation of the misfit stress distribution versus distance from the free surface of the mesa edge; Determination of biaxial misfit stress distribution; Variation of stress values as a function of material and size characteristics of the layer-substrate.

A single crystal X-ray diffraction study of the new compound [Rb([2.2.2]crypt)]2[Rb([18]crown−6)][HGe9]·4NH3 revealed the presence of the first protonated nine-atom germanide cluster [HGe9]3−. It forms from Rb4Ge9 in liquid ammonia, so that [Ge9]4− can be considered as the base and [HGe9]3− its formally conjugated acid. The H atom is attached to a germanium vertex atom of the basal square plane, as it is known for [RGe9]3− (R = C5H9, Mes, etc.) or [HE9]3− (E = Si, Sn). In addition, the proton could be located unambiguously in the Fourier difference map. [HGe9]3− also represents a nido cluster species with 22 cluster-bonding electrons, which can be considered the most stable structure for nine-atom cluster species for all group 14 elements. [ABSTRACT FROM AUTHOR]

We report an effective method to improve the formation of nickel stanogermanide (NiGeSn) by the incorporation of a platinum (Pt) interlayer. After the Ni/Pt/GeSn samples are annealed we obtain uniform NiGeSn thin films, which are characterized by means of sheet resistance, atomic force microscopy, scanning electron microscopy, cross-section transmission electron microscopy, and energy dispersive x-ray spectroscopy. These results show that the presence of Pt increases the smoothness and uniform morphology of NiGeSn films. [ABSTRACT FROM AUTHOR]

In this study, two novel Lu5Pd4Ge8 and Lu3Pd4Ge4 polar intermetallics were prepared by direct synthesis of pure constituents. Their crystal structures were determined by single crystal X-ray diffraction analysis: Lu5Pd4Ge8 is monoclinic, P21/m, mP34, a = 5.7406(3), b = 13.7087(7), c = 8.3423(4) Å, β = 107.8(1), Z = 2; Lu3Pd4Ge4 is orthorhombic, Immm, oI22, a = 4.1368(3), b = 6.9192(5), c = 13.8229(9) Å, Z = 2. The Lu5Pd4Ge8 analysed crystal is one more example of non-merohedral twinning among the rare earth containing germanides. Chemical bonding DFT studies were conducted for these polar intermetallics with a metallic-like behavior. Gathered results for Lu5Pd4Ge8 and Lu3Pd4Ge4 permit to described both of them as composed by [Pd–Ge]δ– three dimensional networks bonded to positively charged lutetium species. From the structural chemical point of view, the studied compounds manifest some similarities to the Zintl phases, containing well-known covalent fragments i.e., Ge dumbbells as well as unique cis-Ge4 units. A comparative analysis of molecular orbital diagrams for Ge26– and cis-Ge10– anions with COHP results supports the idea of the existence of complex Pd–Ge polyanions hosting covalently bonded partially polarised Ge units. The palladium atoms have an anion like behaviour and being the most electronegative cause the noticeable variation of Ge species charges from site to site. Lutetium charges oscillate around +1.5 for all crystallographic positions. Obtained results explained why the classical Zintl-Klemm concept can’t be applied for the studied polar intermetallics. [ABSTRACT FROM AUTHOR]

To enhance the morphological stability of NiGe, a material of interest as a source drain-contact in Ge-based field effect transistors, Ta or W, is added as either an interlayer or a capping layer. The efficacy of this Ta or W addition is evaluated with pure NiGe as a reference. While interlayers increase the NiGe formation temperature, capping layers do not retard the NiGe formation. Regardless of the initial position of Ta or W, the morphological stability of NiGe against agglomeration can be improved by up to 100 °C. The improved thermal stability can be ascribed to an inhibited surface diffusion, owing to Ta or W being located on top of NiGe after annealing, as confirmed by means of transmission electron microscopy, Rutherford backscattering spectrometry, and atom probe tomography. The latter also shows a 0.3 at. % solubility of Ta in NiGe at 450 °C, while no such incorporation of W is detectable. [ABSTRACT FROM AUTHOR]

The solid-phase reaction of ultrathin (⩽10 nm) Ni films with different Ge substrates (single-crystalline (1 0 0), polycrystalline, and amorphous) was studied. As thickness goes down, thin film texture becomes a dominant factor in both the film’s phase formation and morphological evolution. As a consequence, certain metastable microstructures are epitaxially stabilized on crystalline substrates, such as the ϵ-Ni5Ge3 phase or a strained NiGe crystal structure on the single-crystalline substrates. Similarly, the destabilizing effect of axiotaxial texture on the film’s morphology becomes more pronounced as film thicknesses become smaller. These effects are contrasted by the evolution of germanide films on amorphous substrates, on which neither epitaxy nor axiotaxy can form, i.e. none of the (de)stabilizing effects of texture are observed. The crystallization of such amorphous substrates however, drives the film breakup. [ABSTRACT FROM AUTHOR]

Three isostructural transition-metal arsenides and germanides, namely niobium nickel arsenide, Nb 0.92(1) NiAs, niobium cobalt arsenide, NbCoAs, and niobium nickel germanide, NbNiGe, were obtained as inadvertent side products of high-temperature reactions in sealed niobium containers. In addition to reporting for the very first time the structures of the title compounds, refined from single-crystal X-ray diffraction data, this article also serves as a reminder that niobium containers may not be suitable for the synthesis of ternary arsenides and germanides by traditional high-temperature reactions. Synthetic work involving alkali or alkaline-earth metals, transition or early post-transition metals, and elements from groups 14 or 15 under such conditions may yield Nb-containing products, which at times could be the major products of such reactions.