M. P. Suárez

Universidad Nacional de Mar del Plata, Mar de Plata, Buenos Aires, Argentina

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Publications (12)7.41 Total impact

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    ABSTRACT: Surface roughening due to anisotropic wet etching of silicon was studied experimentally and modeled using the Monte Carlo method. Simulations were used to determine the consequences of site-dependent detachment probabilities on surface morphology for a one- and two-dimensional substrate models, focusing on the formation mechanisms of etch hillocks. Dynamic scaling properties of the 1D model were also studied. Resorting to the height–height correlation function and the structure factor, it is shown that the model presents conventional and anomalous scaling (faceted) depending on the stability of the hillocks tops. We also found that there is an intermediate regime that cannot be described by the Family–Vicsek or anomalous scaling ansatz.
    Physica A: Statistical Mechanics and its Applications 01/2014; 395:105–111. · 1.68 Impact Factor
  • D.A. Mirabella, M.P. Suárez, C.M. Aldao
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    ABSTRACT: The formation of two- and three-dimensional hillocks is regularly observed in Si(1 1 1) steps and Si(1 0 0) during wet etching. Frequently the resulting morphology consists of hillocks scattered on a landscape of limited roughness. Recently we proposed a mean field model (MFM) in which the observed hillock-and-valley pattern is possible under steady state if hillock etching is slightly faster than valley etching. This condition implies that hillock size distributions must be an exponential decreasing function. In this work, we report a systematic study of hillock size distributions of experimental morphologies obtained under different etchant concentrations in Si(1 0 0). We found that experimental hillock size distributions are in agreement with those predicted by the MFM.
    Surface Science. 01/2009;
  • D.A. Mirabella, M.P. Suárez, C.M. Aldao
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    ABSTRACT: The formation of etch hillocks was explored in the framework of a site-dependent detachment probabilities model. Monte Carlo simulations were carried out for a one-dimensional substrate within a restricted solid-on-solid model in which only first neighbour interactions are considered. We specifically focus on describing the dynamics that lead to hillock-and-valley patterns. The mechanisms responsible for the steady state morphologies were related to apex creation and annihilation, together with valley and hillock etching, but pattern formation reflects two feedback loops that interrelate these mechanisms.
    Physica A: Statistical Mechanics and its Applications. 03/2008; 387(s 8–9):1957–1962.
  • M. P. Suárez, D. A. Mirabella, C. M. Aldao
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    ABSTRACT: Etch hillocks formation was studied experimentally and modeled using the Monte Carlo method. Simulations were used to explore the consequences of site-dependent detachment probabilities on surface morphology for a one- and two-dimensional substrate models. Comparison with pyramidal etch hillocks that are regularly observed in anisotropic etching of Si(100) are presented. The steady-state morphologies are analyzed and the hillock size distributions determined. The mechanisms responsible for the steady-state morphologies are described.
    Journal of Molecular Catalysis A-chemical - J MOL CATAL A-CHEM. 01/2008; 281(1):230-236.
  • D. A. Mirabella, M. P. Suárez, C. M. Aldao
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    ABSTRACT: We derived a simple mean field model that accounts for the formation of hillock-and-valley patterns after etching in steady state. The mechanisms and their interrelations that lead to these patterns experimentally observed are described. Hillocks and valleys present characteristic size distributions that are governed by the relative etching rates of particles in different sites. In particular, we focus on how etching processes determine the surface morphology and the resulting hillock size distribution. The dependence of these mechanisms on the model parameters is specifically addressed. Monte Carlo simulations were carried out in one dimension using a restricted-solid-on-solid model with nearest neighbor interactions. The outcomes of the mean field model and Monte Carlo simulations are compared.
    Surface Science 01/2008; 602:1572-1578. · 1.87 Impact Factor
  • M. P. Suárez, D. A. Mirabella, C. M. Aldao
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    ABSTRACT: Surface roughening due to anisotropic etching was studied experimentally and modeled using the Monte Carlo method for a Kossel crystal. Simulations were used to explore a possible formation mechanism for the appearance of etch hillocks in two and three dimensions. Similarities with pyramidal etch hillocks that are regularly observed in anisotropic etching of Si(1 0 0) are discussed.
    Surface Science 01/2005; 599:221-229. · 1.87 Impact Factor
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    M. S. Castro, M.P. Suárez, C. M. Aldao
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    ABSTRACT: Varistores de ZnO fueron estudiados mediante el empleo de microscopía y espectroscopía de efecto túnel. Las curvas de corriente túnel vs. tensión indican que las muestras presentan una conducta rectificante. Dado que la conducción en la zona de pre-ruptura es controlada por la formación de barreras de Schottky en los bordes de grano debidas a la presencia de estados intergranulares, las curvas de densidad de corriente vs. temperatura fueron ajustadas considerando la corriente túnel que atraviesa dichas barreras. La altura de las barreras de Schottky determinada con el modelo es comparada con las alturas obtenidas a través del análisis de barrido por espectroscopía túnel (STS) en la región del borde de grano.
    Boletín de la Sociedad Española de Cerámica y Vidrio, ISSN 0366-3175, Vol. 41, Nº. 1, 2002, pags. 143-146. 01/2002;
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    M. S Castro, M. P Suárez, C. M Aldao
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    ABSTRACT: SnO2 thick films have been studied with scanning tunneling microscopy and spectroscopy. Topographic images revealed grains with an average diameter of about 100 nm and roughness of 50 nm. Tunneling current-voltage characteristics measured indicate that these small grains present a non rectifying behavior. Temperature dependence of electrical conductivity during heating and cooling and resistivity transients at step isothermal changes in oxygen pressure were also investigated. Results are consistent with those of STM and confirm that oxygen adsorption and diffusion into the tin oxide grain account for the observed conductance changes.
    Journal of The European Ceramic Society - J EUR CERAM SOC. 01/2001; 21(8):1115-1119.
  • A. Palermo, M. P. Suárez, C. M. Aldo
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    ABSTRACT: Kinetic parameters for desorption of n-tridecane adsorbed on commercial 5A zeolite pellets have been measured. Pre-exponential factors, activation energies, and the populations of each binding state are reported. The results can be quantitatively fitted with a first order desorption rate equation and three different desorption zones could be determined. The possible existence of a compensation effect is qualitatively discussed. Desorption rates for powder and pellets are compared and the influence of initial coverage of pelletized zeolite on population and maximum temperature is presented.
    Thermochimica Acta 01/1996; 286(2):333-340. · 1.99 Impact Factor
  • A. Palermo, M.P. Suarez, C.M. Aldao
    Journal of Catalysis. 07/1994; 148(1):413–414.
  • M. P. Suárez, A. Palermo, C. M. Aldao
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    ABSTRACT: It is generally accepted that the compensation effect arises when a linear relation between InA andE is detected for a simple reaction taking place over different catalysts or for different reactions over one catalyst. For a perfect linear relation between InA andE representation of the reaction rate constant in an Arrhenius plot results in a series of straight lines which intersect in a single point. The importance is stressed of defining unambiguously what is meant by the compensation effect, and it is shown how the scatter in the values of InA is translated into Arrhenius plots.
    Journal of Thermal Analysis 01/1994; 41(4):807-816.
  • Source
    D A Mirabella, M P Suárez, C M Aldao
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    ABSTRACT: Etch hillocks formation was studied experimentally and modeled using the Monte Carlo method. Simulations were used to explore the consequences of site-dependent detachment probabilities on surface morphology for a two-dimensional etching model. Resulting hillock size distribution in steady-state are determined, and the responsible mechanisms involved are proposed and their interrelation explained. Comparison with pyramidal etch hillocks that are regularly observed in anisotropic etching of Si(100) are presented.