Condensation and early stages of gold growth on an Mo (110) surface

The condensation and early stages of gold growth on an Mo (110) surface was studied at various temperatures using the complementary techniques of Auger electron spectroscopy, low energy electron diffraction and thermal desorption spectrometry. The following growth mechanisms were found: a van der Merwe growth mode with no long-range order in the gold layers at 293 K and a Stranski-Krastanov mode favoured by a constrained (111) first layer formation at 933 K.     

Établissement par spectrométrie Auger d'un profil de concentration dans une interface épitaxique: Cas du couple AuAg

In this paper we present the results of our study of the depth profile of the concentration of AuAg and AgAu bilayers using Auger electron spectroscopy during ionic sputtering. We demonstrate a new way of performing the transformation of the graph representing the height of the Auger peaks versus sputtering time to a graph representing concentration versus depth. This profile allows us to find the AuAg interdiffusion coefficient and to note the shift of the interface C = 0.5.     

Resolution correction in EELS

Correction for inelastically scattered electrons is important in determining intensities in elastic peak electron spectroscopy (EPES), e.g. for obtaining information on inelastic mean free paths in the material, relevant parameters in quantitative applications of electron spectroscopy. The spectral shape of electron energy loss spectra depends more strongly on the spectrometer function in the elastic peak region, than in the continuous energy part. Therefore the resolution correction of the EELS spectra results in a considerable change of the spectral shape. The importance and the role of this correction is demonstrated in the case of REELS of Ni sample comparing the shapes of EELS spectra measured at different energy resolutions using different type spectrometers : (1) home-made HSA (ESA 31). Debrecen ; (2) home-made HSA (Clermont Ferrand) ; (3) CMA MAC2 by CAMECA-RIBER and a HSA (Lyon) ; (4) CMA OPC105 type by RIBER (Budapest).     

Simulation and Experimental Studies of Illumination Effects on the Current Transport of Nitridated GaAs Schottky Diode

Semiconductors - In this paper, we studied the electrical characteristic of Schottky diodes based on gold contact on nitridated GaAs substrates. The used (100) GaAs substrate is n-type with...     

Electrical characterization of alumina layers deposited by evaporation cell on Si and restructured InP substrates

In the fast electronic area, studies on InP metal—insulator—semiconductor (MIS) devices have wide interest. Effectively, InP presents a considerable interest due to its high mobility and large bandgap for high speed MIS devices. However, the InP surface must be treated and well passivated before the deposition of insulator. We show that the InSb buffer layer can reduce the phosphorus atom migration and the defects at the interface. After the elaboration of Al₂O₃/Si, Al₂O₃/InP and Al₂O₃:InSb/InP structures, we have studied and characterized electrically the alumina—semiconductor systems. Thus, a mercury probe was used as a temporary gate contact. In the Al₂O₃:InSb/InP structure, the electrical C–V characteristics plotted at 1 MHz give, in the depletion region, a more important slope of the curves. The obtained results show clearly the reduction of the defects, dangling bonds and consequently the state density has been decreased by 50% compared to the InP protected by an InSb buffer layer and no treated surfaces. Then, the interfacial state density N_SS is evaluated as 4 × 10¹¹ eV⁻¹ cm⁻².     

XPS, EPMA and microstructural analysis of a defective industrial plasma-nitrided steel

A multiple analysis of a defective nitrided case has been used to investigate different parts of the over layer region. Experiments by means of X-ray photoelectron spectroscopy (XPS), electron probe microanalysis (EPMA), light microscopy and microhardness measurements were done at different scales and information was given on the structural and physico-chemical properties.The metallographic study allowed estimating the nitrided case depth together with hardness and nitrogen concentration profiles in depth. Also, the irregular nitrogen concentration and the irregular hardness profiles, in a parallel direction to the surface, were correlated with the structure features in the nitrided sample cross-section.One can notice a reasonable connection among the different results, which gives a good understanding of the defective nitrided sample.     

A study of InP(100) surface passivation by antimony deposition

InP(100) is a promising substrate for microelectronic and optoelectronic devices due to its high mobility. Sb atomic condensation induces the formation of some InSb overlayers that produce passivation of the surface. First steps of the mechanism have been studied at atomic scale using synchrotron radiation. The process of InSb formation is due to a 3D-2D phase transformation. In this work we also point out the effect of the sample heating. Results are in good agreement with previous ones obtained by Auger electron spectroscopy (AES) and electron energy loss spectroscopy (EELS). We have obtained a good stabilization of the surface with respect to any prolonged heating up to 450 °C. The size of the In or Sb clusters decreases with temperature: the InSb monolayer becomes almost stoichiometric at 450 °C. The substrate has also a good quality for an optimum behavior of electronic components (L. Bideux, B. Gruzza, A. Porte and H. Robert, Surf. Interface Anal., 20 (1993) 803–807).     

Study and improvement of interfacial properties in a MIS structure based on p-type InP

Indium phosphide is one of the most promising candidates among the available III-V semiconducting compounds for the development of MIS technology. This is based on the availability of InP substrates and the relatively large band gap. Before the deposition of the insulator, the InP surface must be treated and well passivated (Surf Interface Anal 20 (1993) 803; J Appl Phys 67 (1990) 4173). We have shown that a InSb buffer layer can reduce the phosphorus atom migration and the concentration of defects at the interface. We have studied and characterized electrically two series of substrates using p-type InP, the first one with thin and the second with thick insulator films. The results obtained show clearly the reduction of the defects in the thicker structures protected by the InSb buffer layer.