Irreducible tensor-form of the relativistic corrections to the M1 transition operator

The relativistic corrections to the magnetic dipole moment operator in the Pauli approximation were derived originally by Drake (Phys. Rev. A 3(1971)908). In the present paper, we derive their irreducible tensor-operator form to be used in atomic structure codes adopting the Fano-Racah-Wigner algebra for calculating its matrix elements.Comment: 26 page

Formation of NiGe through germanium oxide on Ge(100) substrate

Germanium based devices are of interest due to their pe rformance potential. The use of germanium as source and drain requires low resistance access achieved by the forma tion of germanide (metal-germanium compound). The nickel mono-germanide (NiGe) is claimed to be the best candidate since it presents suitable electrical and thermo-kinetic qualities. However, since the germanium oxidizes instantaneously in air, we provide in this paper a study of reactions between a nanometric Ni film and a germanium (001) substrate in the presence of a native or controlled grown germanium oxide. The goal is to study the influence of the germanium oxide onto germanidation process. We report that whatever the germanium oxide types (native or grown) formation of nickel germanides can occur unlike to silica which limits metal/silicon reactions. Numerous characterizations such as XRD, TEM-EELS, SIMS and SEM lead us to propose a model. Whatever the oxide type as thick as 8nm, nickel react with GeO2 during its deposition and transforms into a continuous germanate layer allowing NiGe nucleation on Ge substrate. After heat treatment the entire Ni layer could react with Ge to form Ni rejecting the germanate NixOyGez toward the sample surface. This mean s that Ni element diffusion occurred even with germinate interlayer. We finally describe several applications for MOS device processes in which this property could be useful

Thermal stability of Ni1-uPtu (0 < u < 0.15) germanosilicide

International audienceSolid-state reactions between Ni1-uPtu (0< u < 0.15 at.%) and Si0.7Ge0.3 after rapid thermal annealing at 280 to 700 degrees C were studied. Numerous physical and chemical characterizations such as sheet resistance analysis, scanning electron microscopy, transmission electron microscopy, Xray diffraction measurement, and atom probe tomography were used to determine the formation and morphological degradation mechanisms of the pure Ni-based germanosilicide. In particular, atom probe tomography was used to quantitatively determine the element distribution in 3D and at the atomic scale. Similar mechanisms for the degradation were found for the Ni mono germanosilicide with and without Pt and led to Ge rich Si1-xGex regions that are etched away by the selective etch. These mechanisms, Ge out-diffusion and agglomeration, have a combined effect on the germanosilicide degradation and occurs through Ge and Ni diffusion, respectively. Adding Pt increases the thermal stability of the layer owing to changes in the phase sequence and texture and strong binding with Ge atoms. Several models are developed to explain the different steps of the film morphological degradation. The thermodynamics description of the equilibrium in the quaternary Ni-Pt-Si-Ge system allows us to rule out a pure thermodynamics explanation for the morphological stabilization due to Pt addition. Published by AIP Publishing

Ni and Ti silicide oxidation for CMOS applications investigated by XRD, XPS and FPP

International audienceAlthough silicide oxidation was studied 20 years ago, the interest of obtaining a robust process for new application appears significant today. Indeed, for the new architectural development process are required dense and narrow spaces. This paper focuses to bury a silicide layer under a protective layer such as silica in order to keep constant the physical and electrical properties of silicide after oxidation. Earlier works show the possibility to oxidize preferably the silicon (Si) in metal contained silicide rather than a pure crystalline Si at high temperatures. Thus, we first tried to reproduce and study these conditions and once acquired, targeted to decrease the oxidation temperature in order to fit with industrial requirements. Titanium (Ti) and Nickel (Ni) are chosen for their metallurgical interest and their integration capability in devices. Thus, four different group/phases (TiSi, TiSi2, Ni2Si, NiSi) of silicide were targeted by adjusting the temperature. In situ X-ray diffraction (XRD), photoelectron spectroscopy and sheet resistance (four point probe) measurements were carried out simultaneously before and after oxidation of silicide to characterize the phase and chemical composition. After silicide formation last three phases (TiSi2, Ni2Si, NiSi) were confirmed by XRD and G1(Ti/Si) was unknown, where only for NiSi was observed the low sheet resistance (≈7.3 Ω/□) and resistivity (18 μΩ·cm). After (dry, wet and plasma) oxidation, the phases of TiSi2 and Ni2Si changed and only NiSi was observed the constant phase, even pure SiO2 was noted on NiSi after wet oxidation

Redistribution of phosphorus during Ni 0.9 Pt 0.1 -based silicide formation on phosphorus implanted Si substrates

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Superconductivity in laser-annealed monocrystalline silicon films: The role of boron implant

International audience33 nm thick silicon on insulator films were implanted with boron at high dose (1.5 × 10$^{16}$ or 2.5 × 10$^{16}$ at/cm$^2$) and low energy (3 or 4 keV), then further annealed with 160 ns laser pulses. When the laser energy is set such as to lead to the near complete melt of silicon, superconductivity is found in 4 keV-implanted films only, with a critical temperature that increases with dose from 270 to 390 mK. This latter temperature is 200 mK higher than the one recently reported in polycrystalline films of same thickness. Transmission electron microscopy images demonstrate that the films annealed at this particular laser energy are monocrystalline, with a lower density of boron precipitates in superconducting ones at a given dose. A simple model shows that the appearance of superconductivity in 4 keV-implanted films is due to the broader shape of the as-implanted boron distribution

Contacts for Monolithic 3D architecture: Study of Ni0.9_{0.9}Co0.1_{0.1} Silicide Formation

Auteur correspondant: "[email protected]"International audienceIn this work, we studied the solid-state reaction between a Ni$_{0.9}$Co$_{0.1}$ film and a silicon substrate. NiCo silicide is considered to substitute Ni-and NiPt-based silicides in 3D integration in order to extend the bottom transistor thermal stability. Thanks to the combined analysis of sheet resistance data, X-ray reflectivity spectra modelling, X-ray diffraction and wavelength dispersive X-ray fluorescence analyses on Ni$_{0.9}$Co$_{0.1}$ /Si samples annealed at various temperatures, we were able to describe the phase sequence of the NiCo silicide formation