A semi-empirical thermochemical study of reactions between methane, atomic hydrogen and a two-dimensionally periodic (111) diamond slab is reported. A sequence of energetically favorable stable surface complexes is established leading to diamond-like growth. The sequence is based solely on these three reactants with the overall charge neutrality of the surface maintained.

The heat of reactions between methyl radicals, atomic hydrogen and a two-dimensionally periodic (111) diamond slab has been calculated using a semi-empirical quantum chemical approach. A sequence of energetically favorable stable surface complexes is established leading to diamond-like growth.

Anomalously fast and slow diffusionperpendicular to the surface in the near surface region of solids have been reported in the literature. The possible reasons of the anomalies are discussed. A simple model is solved to show the effect of the driving force due to surface-free enthalpy excess.

The “Modern Thermodynamic Calculation of Interface Properties” (MTCIP) theory and calculational method is being developed by the authors. In its basic equations the local (interface sublayer) component chemical potentials contain three “unusual” terms reflecting the strongly inhomogeneous character, the constrained existence of the interfaces and the so-called “microstructural parameters”. The use of these terms is—a posteriori—examined and justified on the basis of some from Gyarmati's basic results in the development of Modern Thermodynamics permitting the description of systems even far from equilibrium. In special, considerations and equations related with the famous Thermodynamic Wave Theory and those on the thermodynamic constraint forces are used. In this way the theoretical basis of the MTCIP method is now confirmed by Gyarmati's well-established basic thermodynamic achievements.

Calculations on the stopping power of an electron gas for slow H+ and H+ ions are presented using a frequency dependent local-field correction function within the linear-response theory. Protons are also treated in the elastic binary collisions theory using a screened model potential. For He+ ions, the wave-function of the bound electron is determined self-consistently. Comparisons with Lindhard's linear theory and with the results of nonlinear local density-functional calculations are made.

Cu−Cr multilayer target structures have been investigated by a scanning Auger microprobe in order to determine the profile distortion under ion bombardment. Conclusions are drawn for the depth dependence of the relative depth resolution, and the influence of preferential sputtering is examined at the interfaces.

It is known from previous round robin experiments [1] that relative sensitivity factors, obtained on identical samples by different SIMS instruments, frequently disagreee by a factor of up to 50 and that element concentrations, derived from the raw peak height data by some quantification algorithm, still disagree by a factor of ~5. Two methods, both based on the relative sensitivity factor (RSF) quantification scheme, have been suggested to obtain inter-laboratory standardization of quantitative SIMS analyses: (a) “Standard — Transfer”; for every element/matrix system to be analyzed, a well characterized external standard sample is distributed to each laboratory. Previous to analysis of the unknown, RSFs are determined from the appropriate standard and used for the quantification of the unknown. The method rests on the availability of identical standards in each laboratory and not on the agreement in raw ion intensity data. Each laboratory has to determine its own RSFs previous to each individual analysis. the accuracy is of the order of 20% [2], determined mainly by the accuracy of the standard composition. (b) “Cross-Calibration”; here, the aim is to tune different instruments to give identical RSFs from identical samples. If this can be realized, RSFs can be transferred between instruments and laboratories so that the workload of determining RSFs can be split between laboratories. Standard samples still are required for each unknown/matrix system,but essentially only in that laboratory determining the particular RSF. The accuracy of the method is determined by the quality of the standard and of the instrument tuning.

In the local density approximation (LDA) the stopping power caused by the target electrons is calculated considering the response of an electron gas. Beyond the random phase approximation (RPA) the interaction of the electrons (exchange and correlation effect) is described by the dynamic local field correction. The free atom electron density is modified according to the Gertner model. Considering the interaction between the screened target nucleus and the proton as a classical two body scattering problem, the impact parameter dependence of the “friction force” is determined. The effective stopping power is calculated performing averaging over the volume of the target atom and over impact parameter.

Inelastic energy losses in single collisions are calculated according to the statistical theory of Firsov. The interaction between atoms is described by a potential including additional terms for exchange and correlation energy. A new form of the electronic stopping cross-section is determined.

The expectation value of the electronic stopping power is obtained for different bombarding ions with different bombarding energies impinging in an Ag target. A universal form is fitted to the computer data of high reliability for this case. Energy losses are calculated in the cases of uniatomic bombardment of other element, too. The dependence of the bombarding particle energy and atomic number on the distribution function of ε inelastic andE L elastic energy loss are examined in simulated cascades in Al, Ag and Au targets.

A new evaluation method called EFSA (error function superposition approximation) is proposed, to obtain depth resolution functions on any multilayer structure in agreement with the conventional absolute depth resolution. The quantitative evaluation of Δz measured on multilayer samples helps in clearing up the relations of different interface broadening effects and makes the evaluation independent of the measuring system. It is shown that this method can be successfully applied to both SIMS and AES depth profile measurements and that it has proved to be useful in comparing results obtained in different laboratories.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCross calibration of secondary ion mass spectrometersFriedrich. Ruedenauer, Wolfgang. Steiger, Miklos. Riedel, Horst E. Beske, Horst. Holzbrecher, Michael. Gericke, Carl Ernst. Richter, Michael. Rieth, Manfred. Trapp, and . et al.Cite this: Anal. Chem. 1985, 57, 8, 1636–1643Publication Date (Print):July 1, 1985Publication History Published online1 May 2002Published inissue 1 July 1985https://doi.org/10.1021/ac00285a030RIGHTS & PERMISSIONSArticle Views23Altmetric-Citations10LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1009 KB) Get e-Alerts Get e-Alerts

Energy losses of slow protons in a degenerate electron gas are calculated on the basis of the dielectric theory. The influence of various longitudinal dielectric functions is examined. It is shown that the correlations lead to the decrease of the energy losses in comparison to those stopping power calculations, where only the exchange effects are taken into account. The comparison of the results to the available experimental ones shows a very good agreement.

- The depth resolution of sputter depth profiling has been analysed using Ni-Cr multilayer structures. A new method has been developed to quantify the results. The depth resolu tion measured using polycrystalline metallic layers is strongly influenced by mutual diffusion of the layers. depth resolution of depth profiling SIMS, AES, depth the

The calibrational methods for SIMS use external (MISR(1, 2)) or internal (SAA (3, 4)) standards. The IMISR (Implantation Modificated Matrix Ion Species Ratio) method proposed by us (5) is a combination of these approaches and allows the quantification depth profiles of inhomogeneous samples. Using computer data processing the IMISR quantification can now be performed in five simple steps: 1. implantation of a “standard”, 2. depth profiling of the unknown, 3. depth profiling of the “standard” samples, 4. calibration, 5. (computer) data evaluation.

The inelastic energy loss is calculated in binary atomic collisions with an interaction potential including additional terms for exchange and correlation energy. Our statistical model is based on the generalized Firsov model. Applying the consideration of the classical picture of collisions, we have examined the dependence of the inelastic energy loss on the impact parameter and on the bombarding energy. We used the probability density function of the impact parameter when applying this description on a solid. The results of our calculations are applied on the description of joint physical phenomena. We separately examine the method corresponding to bombarding ions of high and low atomic numbers.

Structural investigations on GaSb crystals grown under microgravity and terrestrial conditions by Bridgman method, are described. Microgravity (μG) conditions resulted in a reasonable quality bi-crystal including its surface layer, as shown by both ion and electron channeling investigations.