In this paper, we report on an in-depth study on the growth of nickel silicides, either on a clean Ni(111) substrate or in the presence of a previously-grown epitaxial single graphene (Gr) layer, by means of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and scanning tunneling microscopy (STM). We demonstrate that two different nickel silicides, namely Ni3Si and Ni2Si, progressively form as the annealing temperature is increased from 450 °C to 600 °C. The presence of the Gr layer does not change the nature of the two silicide phases but rather affects the morphology of the silicide overlayer. Indeed, in the presence of Gr, the deposited silicon atoms intercalate by passing through the Gr defects or domain boundaries and accumulate on specific sample areas, resulting in the formation of multilayer silicide islands. In the absence of Gr, the deposited silicon atoms react uniformly with the nickel substrate, resulting in the formation of homogeneous large scale silicide layers.

An embodiment of an integrated device, including a chip of semiconductor material wherein an integrated circuit is integrated, is proposed; the integrated device includes a set of contact terminals for contacting the integrated circuit. At least one contact terminal of said set of contact terminals includes a contact layer of metal material being suitable to be directly coupled mechanically to an element external to the chip, and a coupling element for improving an electrical and/or mechanical coupling between the contact layer and the chip. The coupling element includes a coupling layer being formed by a combination between the metal material of the contact layer and the semiconductor material of the chip, with the coupling layer that is directly coupled to the chip and to the contact layer.

Ultraviolet (UV) monitoring is of great interest in the healthcare field to prevent excessive UV exposure risks. In the last years silicon carbide (SiC) has emerged as a suitable material for the fabrication of UV detectors. In this paper we propose a 4H-SiC Schottky photodiode with a continuous very thin Ni2Si layer operating at 0V, properly designed for UV radiation monitoring.

Rear contact terminals of integrated circuits have to satisfy electrical and mechanical requirements, such as low specific contact resistance, good adhesion to the substrate and good solderability with external elements. A new metallization scheme, made of sputtered Ni and Au layers, with the addition of a process step needed to ensure nickel silicide formation at low temperature, has been proposed for p-type silicon substrates and investigated in this work. Its electrical and structural properties have been compared with conventional Cr/Ni/Au and Ti/Ni/Au contacts, showing lower specific contact resistance values (rho(c)), an ohmic behaviour in the explored range of resistivity (i.e. 3 m Omega cm < rho < 18 m Omega cm) despite of the rectifying one of conventional materials, better adhesion with the substrate and limited consumption of nickel and silicon during the reaction process. The proposed metallization scheme provides an effective solution to meet both electrical and mechanical requirements with a single material, with a consequent reduction of logistic and economic effort to realize integrated circuits.

Nickel silicide is considered the best candidate material to achieve the lowest contact resistance in sub 45 nm CMOS devices. NiSi films with thickness 20-60 nm were prepared by rapid thermal annealing of Ni (temperature 230 °C-780 °C) on top of thin 230 nm silicon-on-insulator substrates, with a constant formation ratio. Based on film independent characterizations, a novel model for the interpretation of spectroscopic ellipsometry data, featuring a combination of two Lorentzian oscillators and one Drude dispersion model, is proposed, and its goodness is checked in comparison to other known models. This new approach is proved to deliver more accurate estimation of the film thickness and resistivity. © 2012 American Institute of Physics.

Ni-silicide/silicon Schottky contacts have been realised by promoting low-temperature Ni-Si interdiffusion during deposition (50 C) and reaction (450 C) on an oxygen-free [001] silicon surface. A 14nm transrotational NiSi layer was produced made of extremely flat pseudo-epitaxial domains (200nm in diameter). The current-voltage (I-V) characteristics (340-80 K) have indicated the presence of structural inhomogeneities which lower the Schottky barrier by 0:1 eV. They have been associated with the core regions of the trans-domains (wherein the silicide lattice is epitaxially aligned to that of Si) since their density (2:5 109 cm2) and dimension (10 nm) fit the I-V curves vs temperature following the Tung's approach. # 2011 The Japan Society of Applied Physics

Nickel enhanced amorphous Si crystallization and silicidation on polyimide were studied during multipulse excimer laser annealing (ELA) from submelting to melting conditions. A similar to 8 nm thick Ni film was deposited on a 100 nm thick alpha-Si layer at similar to 70 degrees C in order to promote partial nickel diffusion into silicon. In the submelting regime, Ni atoms distributed during deposition in alpha-Si and the thermal gradient due to the presence of the plastic substrate were crucial to induce low fluence (>= 0.08 J/cm(2)) Si crystallization to a depth which is strictly related to the starting Ni profile. Amorphous-Si crystallization is not expected on pure Si at those low fluences. Additional pulses at higher fluences do not modify the double poly-Si/alpha-Si structure until melting conditions are reached. At a threshold of similar to 0.2 J/cm(2), melting was induced simultaneously in the polycrystalline layer as well as in the residual alpha-Si due to a thermal gradient of similar to 200 degrees C. Further increasing the laser fluence causes the poly-Si layer to be progressively melted to a depth which is proportional to the energy density used. As a consequence of the complete Si melting, columnar poly-Si grains are formed above 0.3 J/cm(2). For all fluences, a continuous NiSi2 layer is formed at the surface which fills the large Si grain boundaries, with the beneficial effect of flattening the poly-Si surface. The results would open the perspective of integrating Ni-silicide layers as metallic contacts on Si during alpha-Si-crystallization by ELA on plastic substrate.

The effect of the sputtered Ni layer thickness (7-14 nm) on the silicide phase transition was studied at 260 degrees C. In 7-nm-thick layers, the complete mixing of Ni and Si occurring during deposition produces stable Ni2Si transrotational structures which further evolve into similar NiSi domains within 50 min of annealing. In 14-nm-thick layers, the residual unmixed Ni atoms diffuse towards the interface and speed up the transition from Ni2Si to NiSi (25 min) by promoting the nucleation of polycrystaline NiSi grains. A competition between NiSi trans- and poly-structures occurs, and the resulting layer morphology depends on the reaction temperature. (c) 2006 American Institute of Physics.