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Titanium-based contacts are envisioned for the integration of III–V device contacts on a 300-mm platform, such as photodetectors, semiconductor optical amplifiers (SOAs), and III–V silicon hybrid lasers. For the first time, the impact of the thermal budgets of process integration, back-end of line (BEOL), and long-term thermal stress on the electrical characteristics of the Ti/p-In0.53Ga0.47As and Ti/n-InP contacts has been investigated. Additional physical characterizations have been used to supplement the electrical properties on both systems. Results have indicated that, given a thermal budget between 350 °C and 450 °C during 60 s right after metal deposition, 1) Ti as a contact metal has led to contact resistivity in low 10−5 Ω ⋅ cm2 for p-contacts and in mid 10−5 Ω ⋅ cm2 for n-contacts, which is in accordance with the device requirements; and 2) process integration, BEOL, and long-term thermal stress will not induce any change of the electrical properties. In the scope of III–V silicon hybrid laser contact integration, Ti has hence been evidenced as a suitable candidate for both p- and n-contacts. [ABSTRACT FROM AUTHOR]

Abstract: Thin film germanide reactions are often declared to be the same as silicides reactions which were far more studied. In this paper, we present a comparative study of the phase formation and kinetics of nickel silicides and nickel germanides by several experimental techniques. The samples, composed of a nanometric nickel film (50nm) deposited on silicon or germanium substrates, have been examined by several “in situ” real time measurements: X-ray diffraction (XRD), and differential scanning calorimetry (DSC). These original DSC and “in situ” XRD measurements have allowed us to determine the interfacial reaction rate for Ni2Si using a linear-parabolic law. During the relatively fast DSC ramp, the growth is mainly controlled by the interface while isothermal heat treatments lead to a mainly diffusion control. In contrary to what is usually found for nickel silicide and germanides, a simultaneous growth of Ni5Ge3 and NiGe has been found during “in situ” XRD measurements. The different behavior between the Ni–Si system (sequential formation) and the Ni–Ge system (simultaneous formation) is interpreted in term of diffusion and interface controlled growth. In addition, in devices, the film stability and the stress of the silicides or the germanides can be affected by an important physical characteristic that is the anisotropy of dilatation coefficient. In this work, the lattice parameters and linear thermal expansion coefficients (γ a , γ b and γ c ) of the orthorhombic Ni(Si1− X Ge X ) compounds with 0≤ X ≤1 were determined from high temperature X-ray diffraction data (298–1073K). A negative thermal expansion coefficient of the b lattice parameter of Ni(Si1− X Ge X ) for all the studied Ge concentration was observed: the magnitude of this negative thermal expansion coefficient is decreasing with increasing Ge concentration. [Copyright &y& Elsevier]

Abstract In this work, the solid-state reaction between a 7 nm thick Ni 0.9 Co 0.1 film and a silicon substrate has been studied. By combining various characterization methods (e.g. sheet resistance measurement, X-ray reflectivity, X-ray diffraction), a comprehensive phase sequence of the NiCo silicide formation has been proposed. At low temperature, we observed the formation of metal-rich Ni 2 Si-like phases: δ -(NiCo) 2 Si and θ -(NiCo) 2 Si. Contrary to Ni 0.9 Pt 0.1 based silicides, the δ -Ni 2 Si phase appears before the θ -Ni 2 Si one. Beyond 320 °C, the (NiCo)Si monosilicide formation is initiated and this latter is complete at 400 °C. The presence of Co strongly decreases the NiSi 2 formation temperature. This early formation of disilicide allows avoiding film agglomeration and enhances the thermal stability of NiSi silicide. Complementary studies using wavelength dispersive X-ray fluorescence allowed studying the cobalt behavior and highlighted the formation of a Co composition gradient into the metal-rich silicide phases at relatively low temperature (220–260 °C). Graphical abstract Unlabelled Image Highligh t s • Solid-state reaction between Ni 0.9 Co 0.1 alloy and Si has been fully studied. • The first Ni-rich phase to form is the δ-Ni 2 Si then it is followed by the θ-Ni 2 Si one. • The presence of Co strongly decreases the NiSi 2 formation temperature. • A Co composition gradient into the metal-rich silicide phases has been highlighted. [ABSTRACT FROM AUTHOR]

The development of Complementary Metal Oxide Semiconductor (CMOS)-compatible contact technology on III–V materials based on Ti for electronics or photonics applications was studied. In this framework, solid-state reactions between Ti thin films (20 nm) and In 0.53 Ga 0.47 As layers grown on InP substrates were studied from the as-deposited state up to 550 °C using a combination of advanced X-ray diffraction (in-plane reciprocal space mapping), Auger electron spectroscopy and transmission electron microscopy analyses. The phase formation sequence was solved. At low temperature, an amorphous Ti–Ga–As intermixing layer coexists with the Ti film. As of 250 °C, the first crystalline phase to form is Ti 2 Ga 3. At 300 °C, a new crystalline phase appears, namely TiAs 2. On the other hand, TiAs and metallic In form at 350 °C and Ti is completely consumed between 450 and 500 °C. The diffusion of the various species lead to the formation of a non-nominal Ga-rich In x Ga 1−x As layer and at 550 °C to the formation of polycrystalline GaAs. Ti was found to be the main diffusing species at low temperature whereas III and V elements are the dominant diffusing species at higher temperatures. The nature of the phases formed above and below the original Ti/InGaAs interface might explain the In accumulation at the interface, the TiAs phase acting as a diffusion barrier. [ABSTRACT FROM AUTHOR]