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Examines copper (Cu) silicide formation on SiGeC/Si and SiGe/Si layers. Investigation of Cu reaction with epitaxial SiGeC/Si layers; Comparison between reaction to SiGeC/Si and SiGe/Si layers of Cu; Sequence phase formation of Cu reaction with monocrystalline silicon; Factors influencing the slow supply of Cu atoms to silicide/Si interface.

The morphology of the crystalline–amorphous interface is studied during solid-phase epitaxial crystallization of amorphous GeSi alloy layers with depth-dependent Ge distributions. The interface is shown to undergo an initial strain-induced roughening transition when the Ge concentration exceeds 6.6 at. %. As crystallization continues in strain-relaxed material the interface is shown to further roughen or smooth in response to changes in the Ge distribution. This evolution of the interface morphology is shown to be a consequence of kinetic effects whereby the differential velocity between the leading and trailing edges of the rough interface increases in regions of increasing Ge concentration and decreases in regions of decreasing Ge concentration. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Reports the growth of twin-single crystals of Terfenol-D. Utilization of Czochralski method with cold crucible; Characterization of the quality of twin-free and single-crystalline; Efficiency of the decanting method for direct evidence of unstable growth of single crystal; Impact of the elimination of interface conversion on the single crystal growth.

Proposes a polycrystalline silicon oxidation method to improve surface roughness at the oxide/polycrystalline silicon interface. Observation of surface roughness by transmission electron microscopy and atomic force microscope; Removal of polyoxide layer using buffered hydrofluoric acid; Comparison between the proposed method and conventional oxidation method.

Examines the crystalline quality of ultrathin YBaCuO films on SrTiO[sub 3] and magnesium oxide (MgO) substrates. Display of aligned backscattering spectra in SrTiO films; Protection of YBaCuO films by natural oxide layer; Formation of ytrrium-oxide layer by etching YBaCuO in bromine-methanol.

Examines the crystalline structure near the substrate interface for aluminum films grown on sapphire substrates. Application of metalorganic chemical vapor deposition technique in thin film productions; Role of transmission electron lattice images in depicting interface coherence; Identification of dislocation defect structure of the substrate interface epilayer.

Investigates the interface structure of CeO[sub 2]/Si(111). Result of the reaction between CeO[sub 2] and Si at the interface; Effect of post annealing in oxygen atmosphere on crystalline CeO[sub 2] and SiO[sub 2] thickness; Usefulness of the modified structure of CeO[sub 2]/SiO[sub 2]/Si as a silicon-on-insulator structure.

Presents a model of CoSi[sub 2]/Si(111) interface structure produced by Z-contrast scanning transmission electron microscopy. Implantation of cobalt ions in silicon substrates; Presence of coordinated cobalt atoms at the interface structure; Atomic structure of the buried CoSi[sub 2] layer.

Determines the atomic structure of the B-type gamma-FeSi[sub 2]//Si(111) interfaces by high-resolution transmission electron microscopy. Combination of dynamical calculations of the image contrast in the study; Agreement of one interface model with observations; Attachment of Fe atoms to the substrate silicon atoms.

Presents an ion-beam-induced epitaxial crystallization (IBIEC)/amorphization model at the amorphous silicon interface. Use of IBIEC for recrystallizing damaged layers; Relationship between recrystallization and amorphization; Dependence of crystallization rate on interface orientation.

Performs photoreflectance and photoluminescence experiments to evaluate crystalline quality of indium aluminum arsenide (InAlAs) layers. Observation of electron transport properties between InAlAs and indium gallium arsenide; Performance of high electron mobility transistors; Techniques used in studying crystalline quality of InAlAs layers.

Improving the performance of superconducting qubits and resonators generally results from a combination of materials and fabrication process improvements and design modifications that reduce device sensitivity to residual losses. One instance of this approach is to use trenching into the device substrate in combination with superconductors and dielectrics with low intrinsic losses to improve quality factors and coherence times. Here, we demonstrate titanium nitride coplanar waveguide resonators with mean quality factors exceeding two million and controlled trenching reaching 2.2 μm in the silicon substrate. Additionally, we measure sets of resonators with a range of sizes and trench depths and compare these results with finite-element simulations to demonstrate quantitative agreement with a model of interface dielectric loss. We then apply this analysis to determine the extent to which trenching can improve resonator performance. [ABSTRACT FROM AUTHOR]

GaAs epilayers on Ge substrates are grown with a thin Al0.3Ga0.7As interlayer via metal-organic chemical vapor deposition with the goal of investigating the effect of the Al0.3Ga0.7As interlayer thickness upon the GaAs epilayer. The results show that as the Al0.3Ga0.7As interlayer thickness increases from 0 to 30 nm, both the crystal quality and surface morphology of the GaAs epilayer follow a trend of melioration and then deterioration. All of the Al0.3Ga0.7As interlayers investigated are seen to effectively block the diffusion of Ge atoms to the GaAs epilayers, and high crystalline quality GaAs epilayers with a smooth surface are obtained by growing a 15-23 nm-thick Al0.3Ga0.7As interlayer. [ABSTRACT FROM AUTHOR]

The structure of multi-wall carbon nanotubes has been attributed previously to disordered stacking of the graphene planes. Evidence is presented that the nanotubes analyzed in this paper occur with stacked graphene layers in the sequence of AA′, where alternate graphene planes are translated by half the hexagon width. We further present proof that the crystalline materials comprise graphene helices (∼5 nm in width), rather than in the form of a perfect tube. We also show that the structural model proposed here may be a common structure for multi-wall carbon nanotubes. [ABSTRACT FROM AUTHOR]

This Letter addresses a new finding of the connection between the macroscopic fatigue cracking behaviors of twin boundaries (TBs) and the microscopic TB-dislocation interactions. According to the difference in crystallography beside TBs, slipping dislocations usually interact with TBs in different modes during plastic deformation. In this study, fatigue cracking behaviors at the TBs in Cu and Cu alloys were investigated and compared theoretically and experimentally based on these different interaction modes. The results reveal that the TB-dislocation interactions strongly affect the interfacial strength of TBs through influencing the damage degree by the penetrated dislocations during low-cycle fatigue tests. [ABSTRACT FROM AUTHOR]

The kinetic behavior of quasicrystalline phase formation in amorphous Zr[sub 65]Al[sub 7.5]Cu[sub 12.5]Ni[sub 10]Ag[sub 5] alloys has been studied by using differential scanning calorimetry (DSC), x-ray diffractometry, and transmission electron microscopy. DSC trace obtained during continuous heating from 473 to 873 K shows two distinct exotherms with peak temperatures of 727 and 776 K. The first and second exothermic reactions, respectively, correspond to the formation of quasicrystalline phase from the amorphous matrix and the formation of tetragonal CuZr[sub 2] and hexagonal Zr[sub 6]NiAl[sub 2] phases from the previously formed quasicrystalline phase. Partial replacement of Cu by Ag enhanced the formation of quasicrystalline phase from the amorphous structure. Johnson-Mehl-Avrami analysis of isothermal transformation data suggests that the formation of quasicrystalline phase is not entirely polymorphic in nature and may involve partitioning of solute at a later stage. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A piezoelectric mechanism for the orientation of stripes in two-dimensional electron systems in GaAs-AlGaAs heterostructures is considered. It is shown that when the anisotropy of the elastic constants and the influence of the boundary of the sample are taken into account, the theory gives an orientation of the stripes along [110] direction, in agreement with the experimental data. For a two-layer system an effect is found wherein a reorientation of the stripe structure along the [100] direction occurs when the period of the structure exceeds the distance between layers. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

SiO[sub 2]/Si(111) interfaces formed by a furnace oxidation are studied by a scanning reflection electron microscopy (SREM). SREM observation indicates that the initial atomic steps on a Si(111) surface are preserved at the SiO[sub 2]/Si interface and the interfacial steps do not move laterally even after 48-nm-thick oxidation. A profile analysis of reflection high-energy electron diffraction shows that the SiO[sub 2]/Si interface consists of islands which have a diameter of about 5 nm and monolayer depth. Our results indicate that the layer-by-layer oxidation caused by two-dimensional island nucleation proceeds under furnace oxidation. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]