Surface disorder production during plasma immersion implantation and high energy ion implantation

High-depth-resolution Rutherford Backscattering Spectrometry (RBS) combined with channeling technique was used to analyze the surface layer formed during plasma immersion ion implantation (PIII) of single crystal silicon substrates. Single wavelength multiple angle of incidence ellipsometry (MAIE) was applied to estimate the thickness of the surface layer. The thickness of the disordered layer is much higher than the projected range of P ions and it is comparable with that of protons.\ud \ud Another example of surface damage investigation is the analysis of anomalous surface disorder created by 900 keV and 1.4 MeV Xe implantation in 100 silicon. For the 900 keV implants the surface damage was also characterized with spectroellipsometry (SE). Evaluation of ellipsometric data yields thickness values for surface damage that are in reasonable agreement with those obtained by RBS

Determination of complex dielectric functions of ion implanted and implanted‐annealed amorphous silicon by spectroscopic ellipsometry

Measuring with a spectroscopic ellipsometer (SE) in the 1.8–4.5 eV photon energy region we determined the complex dielectric function (ϵ = ϵ1 + iϵ2) of different kinds of amorphous silicon prepared by self‐implantation and thermal relaxation (500 °C, 3 h). These measurements show that the complex dielectric function (and thus the complex refractive index) of implanted a‐Si (i‐a‐Si) differs from that of relaxed (annealed) a‐Si (r‐a‐Si). Moreover, its ϵ differs from the ϵ of evaporated a‐Si (e‐a‐Si) found in the handbooks as ϵ for a‐Si. If we use this ϵ to evaluate SE measurements of ion implanted silicon then the fit is very poor. We deduced the optical band gap of these materials using the Davis–Mott plot based on the relation: (ϵ2E2)1/3 ∼ (E− Eg). The results are: 0.85 eV (i‐a‐Si), 1.12 eV (e‐a‐Si), 1.30 eV (r‐a‐Si). We attribute the optical change to annihilation of point defects

Nucleon-resonance decay by the K-0 Sigma(+) channel near threshold

For the combined setup of the Crystal Barrel and TAPS at ELSA in Bonn we have proposed to study the reaction gammap --> K(0)Sigma(+). The reaction is characterised by the final state of 6 photons and a forward emitted proton. Here we report on results of simulations to demonstrate the feasibility of the experiment. From the threshold behaviour of the cross section and angular distributions we aim to search for a 3(rd) S-11 resonance just above the KSigma threshold, which may mix with the two lower lying S-11 resonances and thus provide an explanation for the unusually strong eta branching of the S-11(1535) resonance. The hyperon polarisation can be studied as a sensitive tool to determine the various resonance admixtures

Etiological diagnosis in limb reduction defects and the number of affected limbs:A population-based study in the Northern Netherlands

Limb reduction defects (LRDs) that affect multiple limbs are considered to be more often heritable, but only few studies have substantiated this. We aimed to investigate if an etiological diagnosis (genetic disorder or clinically recognizable disorder) is more likely to be made when multiple limbs are affected compared to when only one limb is affected. We used data from EUROCAT Northern Netherlands and included 391 fetuses and children with LRDs born in 1981-2017. Cases were classified as having a transverse, longitudinal (preaxial/postaxial/central/mixed), intercalary, or complex LRD of one or more limbs and as having an isolated LRD or multiple congenital anomalies (MCA). We calculated the probability of obtaining an etiological diagnosis in cases with multiple affected limbs versus one affected limb using relative risk (RR) scores and Fisher's exact test. We showed that an etiological diagnosis was made three times more often when an LRD occurred in multiple limbs compared to when it occurred in one limb (RR 2.9, 95% CI 2.2-3.8, p <0.001). No genetic disorders were found in isolated cases with only one affected limb, whereas a genetic disorder was identified in 16% of MCA cases with one affected limb. A clinically recognizable disorder was found in 47% of MCA cases with one affected limb. Genetic counseling rates were similar. We conclude that reduction defects of multiple limbs are indeed more often heritable. Genetic testing seems less useful in isolated cases with one affected limb, but is warranted in MCA cases with one affected limb