Kinetics of silicide formation over a wide range of heating rates spanning six orders of magnitude (2025)

Formation of Pd2Si on single-crystalline Si (100) at ultrafast heating rates: An in-situ analysis by nanocalorimetry

Applied Physics Letters, 2013

The kinetics of intermediate phase formation between ultrathin films of Pd (12 nm) and single-crystalline Si (100) is monitored by in-situ nanocalorimetry at ultrafast heating rates. The heat capacity curves show an exothermic peak related to the formation of Pd 2 Si. A kinetic model which goes beyond the conventional linear-parabolic growth to consider independent nucleation and lateral growth of Pd 2 Si along the interface and vertical growth mechanisms is developed to fit the calorimetric curves. The model is used to extract the effective interfacial nucleation/growth and diffusion coefficients at the unusually high temperatures of silicide formation achieved at very fast heating rates. V

Simultaneous nanocalorimetry and fast XRD measurements to study the silicide formation in Pd/a-Si bilayers

Journal of Synchrotron Radiation, 2015

The use of a membrane-based chip nanocalorimeter in a powder diffraction beamline is described. Simultaneous wide-angle X-ray scattering and scanning nanocalorimetric measurements are performed on a thin-film stack of palladium/amorphous silicon (Pd/a-Si) at heating rates from 0.1 to 10 K s−1. The nanocalorimeter works under a power-compensation scheme previously developed by the authors. Kinetic and structural information of the consumed and created phases can be obtained from the combined techniques. The formation of Pd2Si produces a broad calorimetric peak that contains overlapping individual processes. It is shown that Pd consumption precedes the formation of the crystalline Pd2Si phase and that the crystallite size depends on the heating rate of the experiment.

Phase Transitions in Amorphous Si Produced by Rapid Heating

Physical Review Letters, 1980

Amorphous Si layers have been melted by pulsed electron irradiation. Implanted As has been. used as a marker for determining melt duration. Systematic differences between As diffusion in initially amorphous or crystalline Si are interpreted in terms of different enthalpies of melting between amorphous (1220 J/g) and crystalline (1790 J/g) Si. The implanted amorphous layers melt and crystallize at significantly lower electron energies than those required to melt and recrystallize crystalline Si, indicating that amorphous Si melts at 1170 K compared to 1685 K for crystalline Si.

Silicide formation and dopant diffusion in silicon

Physical review. B, Condensed matter, 1992

Recently, we reported that formation of Pd2Si from Pd induced asymmetric diffusion of buried dopant marker layers in the silicon substrate at surprisingly low temperatures (-200'C) [M. Witt

Kinetics of formation of silicides in a-Si:H/Pd interfaces monitored by in situ ellipsometry and kelvin probe techniques

Journal of Non-Crystalline Solids, 1991

We report the formation of palladium silicides during the exposure of Pd substrates to silane and/or to an rf glow discharge used for a-Si:H deposition. By the use of two in situ techniques (ellipsometry and Kelvin probe) we monitor the kinetics of the reaction of the silane gas and/or of the a-Si:H film with the Pd substrate. The characterization of the samples by Rutherford Backscattering Spectrometry (RBS) allows us to accurately determine the resulting profiles of Pd and silicon. We found that even without plasma Pd2Si is formed by the exposure of a 500-1500 A Pd film to the silane at 250°C.

Theoretical Study of the Heats of Formation of Small Silicon-Containing Compounds

The Journal of Physical Chemistry A, 1999

Heats of formation for nine small silicon-containing molecules were obtained from large basis set ab initio calculations using coupled cluster theory with a perturbative treatment of triple excitations. After adjusting the atomization energies for the finite basis set truncation error, core/valence correlation, scalar relativistic, higher order correlation, and atomic spin-orbit effects, the theoretical and experimental 0 K values of ∆H f values were in good agreement. Using 106.6 kcal/mol as the heat of formation of silicon, we obtain ∆H f values of SiH ) 87.7 ( 0.4 vs 89.5 ( 0.7 (expt); SiH 2 ( 1 A 1 ) ) 64.1 ( 0.4 vs 65.5 ( 0.7 (expt); SiH 2 ( 3 B 1 ) ) 85.4 ( 0.4 vs 86.5 ( 0.7 (expt); SiH 3 ) 47.3 ( 0.5 vs 47.7 ( 1.2 (expt); SiH 4 ) 8.7 ( 0.6 vs 9.5 ( 0.5 (expt); Si 2 ) 138.8 ( 0.4 vs 139.2 (expt); Si 2 H 6 ) 19.7 ( 0.5 vs 20.9 ( 0.3 (expt); SiF ) -14.8 ( 0.4 vs -5.2 ( 3 (expt); SiF 2 ) -151.7 ( 0.5 vs -140.3 ( 3 (expt); and SiF 4 ) -384.5 ( 0.9 vs -384.9 ( 0.2 (expt). Based on the present work, we suggest a number of revisions in the interpretation of the experimental data. Although a revision in ∆H f°( Si) to 107.4 ( 0.6 kcal/mol at 0 K leads to improved agreement between theory and experiment for the Si x H y compounds, it worsens agreement for SiF 4 . Given the remaining uncertainties in the theoretical approach, more definitive conclusions do not appear to be warranted.

Reaction Diffusion in Mo-Si System Above the Melting Point of Silicon

2005

The results of direct kinetic measurements and SEM observations on formation of silicide phases in Mo-Si system at temperatures 1400-1700 о С are presented in the work. It was shown, that the formation of MoSi 2 proceeds by two different mechanisms and accordingly, two types of microstructures are formed: (i) a compact layer (usually with expressed columnar structure) by the reaction diffusion mechanism; and (ii) separated fine grains by crystallization in the volume of saturated Me-Si melt. A model of product formation is offered which allows to calculate the relative contributions of the two mechanisms of disilicide phase formation at various stages of interaction and to estimate the role each of them in the total process. Experimental Experiments were conducted using electrothermography method [4]. Molybdenum thin wires (ESPI Metals, 3N8, >99,97 % purity) 100 µm in diameter and working length ~10 cm were used as source materials. The essence of the method consists in heating of metallic samples (sometimes with a reagent layer deposited on its surface) by passage of direct electrical current in the inert or reactive

Linear growth kinetics of nanometric silicides in Co/amorphous-Si and Co/CoSi/amorphous-Si thin films

Journal of Applied Physics, 2008

Evolution of the reaction zone on the nanoscale has been studied in bi-and multilayered Co/a-Si as well as in trilayered Co/a-CoSi/a-Si and Co/CoSi/a-Si thin film diffusion couples. The kinetics of the phase boundary movement during solid state reaction has been followed with special interest of the initial stage of the diffusion, i.e. effects happening on the nanoscale ͑short time, short distance͒. The interfacial reactions have been investigated in situ by synchrotron radiation. The formed phases were also characterized by transmission electron microscopy and resistance measurements. The effect of phase nucleation and shift of phase boundaries have been separated in order to determine the "pure" growth kinetics of the crystalline CoSi and Co 2 Si product phases at the very early stages. Deviations have been found from the traditional diffusion controlled parabolic phase growth. Computer simulations based on a kinetic mean field model illustrated that the diffusion asymmetry ͑large difference in diffusion coefficients of the materials in contact͒ may offer a plausible explanations for this.

Specific Heat and Melting Temperature of Relaxed and Unrelaxed Si Amorphous States

MRS Proceedings, 1990

Direct picosecond laser measurements of the critical fluence for melting have been performed for the first time, giving unambiguously consistent differences in the energy required for surface melting of relaxed and unrelaxed amorphous silicon. The different optical coupling cannot account for this variation which can only be explained in term of different melting temperatures. Heating of unrelaxed amorphous silicon samples at temperatures close to the melting point may result in relaxation of the material even when the treatment occurs in the nanosecond time scale. However nanosecond UV irradiation of relaxed and unrelaxed amorphous silicon samples have provided informations on the specific heat of the two amorphous states. The melting temperature of unrelaxed amorphous silicon has been derived independently via both picosecond data and via free energy calculations.

A simple model for the growth of polycrystalline Si using the kinetic Monte Carlo simulation

Modelling and Simulation in Materials Science and Engineering, 2000

An extension to the kinetic Monte Carlo simulation technique was developed in order to study thin film deposition and growth of a system approximating polycrystalline silicon. This method was developed to determine the effect of varying the angle of incidence of an atomic beam on the morphology of a poly-Si thin film grown on a crystalline Si substrate. This deposition procedure produced material comprised of individual grains, all with identical orientation; a first step towards modelling poly-Si. The addition of such grains does not significantly affect the bulk film properties relative to the single crystal case. The number of initial grains chosen to represent a set of pre-existing grains on the surface does not affect the gross morphology of the grown film once around 40 monolayers have been deposited. The chief advantage of this polycrystalline-like system is that it allows the observation of both columnar growth (at angles below about 65 • ) and dendritic growth at angles above this value; growth of single crystalline material only shows the latter. This fact allows a comparison of results from atomic-scale simulation to existing theories that relate the angle of the morphological features of the grown film to the angle of the incident beam. We show that the simulation data are not particularly well represented by commonly used theories such as the tangent rule, or that due to Tait et al (1993 Thin Solid Films 226 196). Increased angles of incidence cause faster extinction of grains until a steady-state value of the number of grains is reached. When grains are nucleated on a heterogeneous substrate, here chosen as a crude description of Si on glass, increased substrate temperature results in larger grains, and higher angles of incidence result in fewer nucleated grains due to non-local shadowing.