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Provides information on a study which investigated the dissociation behavior of dilute, immiscible thin films of copper-alloy. Details on the experiment; Results and discussion.

Differential scanning calorimetry, in conjunction with x-ray and electron diffraction, is used to investigate the A1 to L10 ordering transformation in binary FePt films with compositions in the range of 47.5 to 55 at. % Fe, and in ternary alloys of FePt with Cu, Co, Ag, and Au. The lowest kinetic ordering temperatures, in the range of 355–375 °C, are found for Fe-rich binary FePt alloys, namely, Fe53Pt47 and Fe55Pt45, and for ternary FePt-Cu alloys that have the same amount of Pt as these binary alloys, namely, Fe50Cu3Pt47 and Fe50Cu5Pt45. Ternary additions of Co (28 at. %), Ag (11 at. %), and Au (7 and 12 at. %) increase the kinetic ordering temperature when compared to the equiatomic, binary FePt alloy. The activation energies of ordering lie between 1.6 and 1.9 eV, except for the Fe47Pt46Au7 alloy, for which the activation energy is 2.2 eV. The transformation enthalpies are in the range of -6.3 to -13.2 kJ/g atom. The Curie temperatures for the binary FePt alloys increase from 379 to 456 °C in the composition range 47.5 to 55 at. %. Ternary additions have a complex effect on the Curie temperature. However, the Curie temperatures of the ternary Fe-Pt-Cu alloys, with Cu additions of 1–5 at. %, were lower (370–407 °C) than the binary FePt alloys of equal Pt content. Au is seen to phase separate from FePt. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Dissolution kinetics of cobalt in liquid 87.5%Sn–7.5%Bi–3%In–1%Zn–1%Sb and 80%Sn–15%Bi–3%In–1%Zn–1%Sb soldering alloys and phase formation at the cobalt–solder interface have been investigated in the temperature range of 250–450 °C. The temperature dependence of the cobalt solubility in soldering alloys was found to obey a relation of the Arrhenius type cs = 4.06 × 102 exp (−46300/ RT) mass% for the former alloy and cs = 5.46 × 102 exp (−49200/ RT) mass% for the latter, where R is in J mol−1 K−1 and T in K. For tin, the appropriate equation is cs = 4.08 × 102 exp (−45200/ RT) mass%. The dissolution rate constants are rather close for these soldering alloys and vary in the range (1–9) × 10−5 m s−1 at disc rotational speeds of 6.45–82.4 rad s−1. For both alloys, the CoSn3 intermetallic layer is formed at the interface of cobalt and the saturated or undersaturated solder melt at 250 °C and dipping times up to 1800 s, whereas the CoSn2 intermetallic layer occurs at higher temperatures of 300–450 °C. Formation of an additional intermetallic layer (around 1.5 μm thick) of the CoSn compound was only observed at 450 °C and a dipping time of 1800 s. A simple mathematical equation is proposed to evaluate the intermetallic-layer thickness in the case of undersaturated melts. The tensile strength of the cobalt-to-solder joints is 95–107 MPa, with the relative elongation being 2.0–2.6%. [ABSTRACT FROM AUTHOR]

To address the future use of alloying elements for Cu interconnect applications in integrated circuits, first, available bulk experimental data such as residual resistivity per at. % solute and binary phase diagrams are used to arrive at a set of 24 potential elements. Next, experimental results in thin films and lines allow the authors to arrive at a smaller set that includes ten elements, namely, Pd, Au, Al, Ag, Nb, Cr, B, Ti, In, and Mn, with higher priority and six, namely, Zn, V, C, Mg, P, and Sn with lower priority for further studies. These additional studies are needed before a strong case for or against alloying additions to Cu can be made. The available thin film and line data are summarized in a series of tables that should prove useful for the readers. In particular, the thin film data allow the authors to obtain an effective average residual resistivity (EARR) per at. % solute that combines the effects of impurity scattering, second phase precipitates, and grain size refinement resulting from solute additions. [ABSTRACT FROM AUTHOR]

This letter describes materials and electrical characterization of Pt-Ru binary alloy metal gate electrodes for control of the electrode work function. The work function of the Pt-Ru binary alloy system can be tuned over a wide range of 4.8–5.2 eV. The results indicate that the change of film properties, i.e., resistivity, work function, and crystal structure, with composition is consistent with the equilibrium phase diagram and that the work function in the face-centered cubic and hexagonal close-packed single-phase regions is only weakly dependent on composition, whereas a strong dependence is observed in the intermediate compositional range. [ABSTRACT FROM AUTHOR]

The resistivities of as-deposited Cu(4.2Ir), Cu(2.0W), and Cu(2.2W) films are 32.2, 25.4, and 28.0 µΩcm, respectively. These resistivities are significantly higher than that for pure Cu films. After annealing the Cu(4.2Ir) film at constant heating rate to 800 °C and the two Cu(W) films to 950 °C, the resistivities reduce to 28.4, 4.3, and 5.2 µΩcm, respectively. The smaller reduction in resistivity for Cu(4.2Ir) compared with that for Cu(W) is partly a consequence of solute redissolution following precipitation. The variation of resistivity with temperature for the films and the Cu-rich end of the binary phase diagrams are used to categorize the decomposition behavior of the Cu(Ir) and Cu(W). These categories were defined by K. Barmak et al., J. Appl. Phys. 87, 2204 (2000). W is placed in category III along with V, Nb, Ta, Cr, Mo, Re, Ru, Os, B, and C. Ir most suitably belongs to Category II together with Fe and Co. [ABSTRACT FROM AUTHOR]

The impact of 11 alloying elements, namely Mg, Ti, In, Sn, Al, Ag, Co, Nb and B, at two nominal concentration of 1 and 3 at%, and Ir and W, at only a nominal concentration of 3 at%, on the evolution of texture of Cu was investigated. The behavior of the alloy films was compared with that for a pure Cu film. The films were electron beam evaporated onto oxidized Si wafers and had thicknesses in the range of 420–560 nm. Annealing was carried out at 3°C/s to 400°C, 650°C and 950°C. For the lowest annealing temperature, the samples were held isothermally for 5 h, while for the higher annealing temperatures, the samples were cooled immediately after reaching temperature. In all cases, annealing resulted in the strengthening of film texture. For most of the films, the 〈1 1 1〉 component either remained or became the strongest fiber component with the increase in annealing temperature. The interesting exceptions were the two Mg-containing films for which the 〈1 1 0〉 component was the strongest. Whereas in the as-deposited state all alloy films, except the nominally 3 at% Nb film, had weaker textures than pure Cu, certain combinations of alloy concentration and annealing conditions resulted in more strongly textured films when compared with pure Cu. For example, the most strongly textured film after the 400°C and 950°C anneals were, respectively, Cu(Ti) and Cu(Nb), both nominally 3 at%. Film texture was also related to grain growth for the 400°C-annealed films. The behavior of the alloy films is discussed in terms of the various driving and pinning forces for grain growth and texture evolution in thin films. No simple correlations of alloy film behavior with atom size, electronegativity or the binary alloy phase diagram were found. [Copyright &y& Elsevier]

Abstract: Ternary FeCuPt alloys with 1–5at.% Cu produced no advantage over equivalent binary FePt alloys in terms of lowering the kinetic ordering temperature. The Curie temperature decreased with increasing Cu content. The transformation enthalpy and activation energy were not affected. [Copyright &y& Elsevier]