Abstract— The manufacture of large‐area arrays of thin‐film transistors on polymer substrates using roll‐to‐roll (R2R) processes exclusively is being developed. Self‐aligned imprint lithography (SAIL) enables the patterning and alignment of submicron‐sized features on meter‐scaled flexible substrates in the R2R environment. SAIL solves the problem of precision interlayer registry on a moving web by encoding all the geometry information required for the entire patterning steps into a monolithic three‐dimensional imprint with discrete thickness modulation. The pre‐aligned multiple‐step mask structure maintains its alignment regardless of subsequent substrate distortion. Challenges are encountered in relation to the novel nature of using flexible substrates and building toolsets for the R2R processing. In this paper, methods of the SAIL process, the resulting active‐matrix backplanes, the trajectory of SAIL process development, and the remaining issues for production are presented.
Using spectroscopic ellipsometry, we measured the pseudodielectric function of Si1−x−yGexCy alloys (0≤x≤0.48,0≤y≤0.05) grown on Si(001) using molecular beam epitaxy. For pseudomorphically strained layers, the energy shifts of the E1, E1+Δ1, E0′, and E2 transitions are determined by line shape analysis and are due to alloy composition effects, as well as hydrostatic and shear strain. We developed expressions for hydrostatic and shear shift from continuum elasticity theory, using deformation potentials for Si and Ge, for biaxial stress parallel to the (001) growth plane in a diamond or zinc blende-type crystal and applied this to the ternary Si–Ge–C alloy. The energies of E1 and its spin-orbit split partner E1+Δ1 agree fairly well with theory. The E2 transitions in Si1−xGex at around 4.3 eV depend linearly on Ge concentration. In case of relaxed layers, the E1 and E1+Δ1 transitions are inhomogeneously broadened due to the influence of misfit and threading dislocations. For a silicon cap on top of a dislocated, relaxed SiGe layer, we recovered the bulk Si dielectric function.
Spectroscopic ellipsometry was used to measure the dielectric functions of epitaxial and bulk Ge at photon energies from 1.5 to 5.2 eV. The epitaxial Ge was grown at 400°C by molecular beam epitaxy on ͑001͒ Si substrates. The optical response and the interband critical-point parameters of Ge on Si were found to be indistinguishable from that of bulk single crystal Ge, indicating high optical quality. Dislocation density measurements using an iodine etch verified low surface defect densities. We conclude that epitaxial Ge grown on Si at relatively low temperatures is suitable for optical device applications.
Abstrad. The 3ET.neutron emission profile monitor was used to study ohmically heated deuterium discharges. The radial profile of the neutron emissivity is deduced from the line-integral data. The profiles of ion temperamre, T, and ion thermal dfisivity, xi, are derived under steady-state conditions. The inferred xi, for 0.3 < p = ,/a < 0.5, is in the &ge 0.5-2.5m2s-'. The ion thermal difisivity is higher than. and its scaling with plasma current opposite to, that predicted by neoclassical theory.
We measured the pseudodielectric function (PDF) of Ge1-yCy and Ge-rich Si1-x-yGexCy alloys from 1.1 to 5.2 eV using spectroscopic ellipsometry. These alloys were grown by molecular beam epitaxy at 6000C on (001) Si substrates. Analytical lineshapes fitted to numerically calculated derivatives of their PDFs determined the critical-point parameters of the E1, E1+Δ1, E0', and E2 transitions. The critical-point energies of the Ge1-yCy alloys were found to be similar to bulk Ge. This indicates that the presence of C in these alloys only has a small influence on the band structure. For some samples, the amplitude of the PDF is much lower than in bulk Ge, which can be attributed to surface roughness and explained within the framework of the Kirchhoff theory of diffraction or using effective medium theory. The degree of surface roughness indicated by optical measurements was confirmed by atomic force microscopy. We also studied bulk Czochralski-grown Si1-xGex alloys (0<x<0.28) doped with boron. Due to doping, the critical points shift to lower energies as reported previously for bulk Si and Ge.
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