Reference-free x-ray fluorescence analysis with a micrometer-sized incident beam.

Spatially resolved x-ray fluorescence (XRF) based analysis employing incident beam sizes in the low micrometer range (µXRF) is widely used to study lateral composition changes of various types of microstructured samples. However, up to now the quantitative analysis of such experimental datasets could only be realized employing adequate calibration or reference specimen. In this work, we extent the applicability of the so-called reference-free XRF approach to enable reference-freeµXRF analysis. Here, no calibration specimen are needed in order to derive a quantitative and position sensitive composition of the sample of interest. The necessary instrumental steps to realize reference-freeµXRF are explained and a validation of ref.-freeµXRF against ref.-free standard XRF is performed employing laterally homogeneous samples. Finally, an application example from semiconductor research is shown, where the lateral sample features require the usage of ref.-freeµXRF for quantitative analysis.

Taming the Distribution of Light in Gate-All-Around Semiconductor Devices.

Optical metrology is ubiquitous, but image-based methods cannot resolve features of dimensions much smaller than the wavelength. However, it has recently been demonstrated that light can be nanofocused into subwavelength semiconducting lines by setting the incident polarization along the direction of these lines. This Letter extends the previous studies to systems with two perpendicular gratings, as found e.g. after replacement gate processing of gate-all-around (GAA) field-effect transistors (FETs). We show that besides the nanofocusing effect, the incident polarization also offers control over which array of lines the light couples into. The interaction of the incident light occurs with the semiconducting lines to which the polarization is parallel with remarkably low interference from the existence of another perpendicular grating. We demonstrate the use of this effect with Raman spectroscopy to simultaneously extract the SiGe volume and the strain in the Si forksheet channels and in the SiGe layers of GAA FETs.

Polarization-selective plasmon-enhanced silicon quantum-dot luminescence.

The photoluminescence intensity of silicon quantum dots is enhanced in a polarization-selective way by coupling to elongated Ag nanoparticles. The observed polarization dependence provides direct proof that the PL enhancement is due to electromagnetic coupling of the silicon quantum-dot emission dipoles with dipolar plasmon modes of the Ag nanoparticles. The polarization selectivity demonstrates the potential of engineered plasmonic nanostructures to optimize and tune the performance of light sources in a way that goes beyond solely enhancing the emission and absorption rates.

[Training and educational measures in severe chronic heart failure. Experiences and application to general practice]. / Trainings- und Schulungsmassnahmen bei schwerer chronischer Herzinsuffizienz. Erfahrungen und Umsetzung in der Praxis.

OBJECTIVES: Prognosis and course of severe left ventricular dysfunction have been shown to be influenced positively by exercise training. Yet, physicians have been reluctant to include exercise into therapeutic concepts due to widespread uncertainty about the acceptable intensity of cardiac stress. Standardized exercise programs with proven safety may promote acceptance of this approach. PATIENTS AND METHODS: 25 patients with severe heart failure were enrolled in a PC-controlled interval exercise training on cycle ergometer, lasting 21 minutes five times a week for a 4-week inpatient period. After discharge patients performed incremental daily walking for 3 months. Associated educational measures concerned life-style changing and self-controls. RESULTS: None of the patients had to interrupt the training because of side effects. 3 weeks and 3 months after starting exercise training there was an increase of peak VO2 from 13.4 +/- 2.8 to 14.5 +/- 3.8 (p < 0.05) and 15.3 +/- 3.2 ml/kg/min (p < 0.01), respectively, and an increase of ventilatory anaerobic threshold (VAT) from 9.3 +/- 1.9 to 10.0 +/- 2.3 (p < 0.05) and 11.3 +/- 2.2 ml/kg/min (p < 0.001), respectively. The improved aerobic capacity corresponded to a 9.3% increase in the results of the 6-minute walk test in the 4th week (n.s.). During out-patient period, the walking could be increased from 37 to 58 minutes daily. The physical quality of life was significantly improved after 3 months. There was no hospital admission due to heart failure. CONCLUSION: Exercise training in the therapy of severe heart failure is safe and increases the aerobic capacity. Associated educational measures may be able to minimize the danger of wrong exercise techniques and to reduce the rate of hospital readmissions.