350 research outputs found
A new spectrometer for grazing incidence X-ray fluorescence for the characterization of Arsenic implants and Hf based high-k layers
No full textGrazing Incidence X-ray Fluorescence Analysis (GIXRF) takes advantage of the total external reflection of X-rays on a smooth, polished surface. Due to the penetration depth of only a few nanometers at very small incidence angles, GIXRF is able to probe the elemental composition in the near surface region of the sample. Furthermore by adjusting the angle of incidence and measuring the angle-dependent X-ray fluorescence signals, the technique is able to provide information on the total dose and depth distribution of the elements. The depth profile information is ambigous, thus the evaluation process, which consists of fitting the measured data to simulations, needs additional input from another technique. In the present work a GIXRF measuring chamber is presented, which was designed, constructed and tested within the context of the EC funded European Integrated Activity of Excellence and Networking for Nano and Micro-Electronics Analysis (ANNA) . Moreover an acquisition and control software and a measurement protocol were developed and tested. GIXRF measurements for the characterization of Ultra Shallow Junctions (USJ) were used to ascertain the performance of the new instrument. Secondary Ion Mass Spectrometry (SIMS) was used as a complementary technique for the depth profile evaluation. The dose quantification of the implanted Arsenic was compared with Instrumental Neutron Activation Analysis (INAA) and SIMS. Furthermore Hafnium based high k layers on Silicon were analyzed and the results compared to other techniques of the ANNA partners. Part of this work has been published in the following publications: 1. D. Ingerle, F. Meirer, N. Zoeger, G. Pepponi, D. Giubertoni, G. Steinhauser, P. Wobrauschek, C. Streli, A new spectrometer for grazing incidence X-ray fluorescence for the characterization of Arsenic implants and Hf based high-k layers, Spectrochimica Acta Part B: Atomic Spectroscopy 65 (6) (2010) 429-433. doi:10.1016/j.sab.2004.04.014 2. G. Pepponi, D. Giubertoni, M. Bersani, F. Meirer, D. Ingerle, G. Steinhauser, C. Streli, P. Hoenicke, B. Beckhoff, Grazing incidence x-ray fluorescence and secondary ion mass spectrometry combined approach for the characterization of ultrashallow arsenic distribution in silicon, Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures 28 (1) (2010) C1C59. doi:10.1116/1.3292647 3. D. Giubertoni, G. Pepponi, B. Beckhoff, P. Hoenicke, F. Gennaro, F. Meirer, 4 D. Ingerle, G. Steinhauser, M. Fried, P. Petrik, A. Parisini, M. A. Reading, C. Streli, J. van den Berg, M. Bersani, Multi-technique characterization of arsenic ultra shallow junctions in silicon within the ANNA consortium, AIP Conference Proceedings 1173 (2009) (2009) 45-49. doi:10.1063/1.325125
A new total reflection X-ray fluorescence vacuum chamber with sample changer analysis using a silicon drift detector for chemical analysis
No full textThere are several TXRF spectrometers commercially available for chemical analysis as well as for wafer surface analysis, but there is up
to now no spectrometer for chemical analysis available that allows to measure samples under vacuum conditions. Simply a rough vacuum of
10 2 mbar for the sample environment reduces the background due to scattering from air, thus to improve the detection limits. The
absorption of low energy fluorescence radiation from low Z elements is reduced and therefore extends the elemental range to be measured
down to Na. Finally evacuation of the chamber removes the Ar K-lines from the spectrum.
The new vacuum chamber for TXRF named WOBISTRAX is equipped with a 12-position sample changer, a 10-mm2 silicon drift
detector (SDD) with an 8-Am Be entrance window and electrical cooling by Peltier effect, so no LN2 is required. The chamber was designed
to be attached to a diffraction tube housing. WOBISTRAX can be operated with a 3 kW long fine focus Mo-X-ray tube and uses a Mo/Si
multilayer for monochromatization. The modified software is performing the motion control between sample changer and MCA features.
The performance is expressed in terms of detection limits which are 700 fg Rb for Mo Ka excitation with 50 kV, 40 mA excitation
conditions, 1000 s livetime. Using a Cr-X-ray tube for excitation of Al the achieved detection limits are 52 pg. So it could be shown that with
the same measuring chamber and using an SDD with 8 Am Be window and a Cr-tube for excitation, low Z elements can be also measured
with good detection limit
Grazing exit versus grazing incidence geometry for x-ray absorption near edge structure analysis of arsenic traces
No full textIn the presented study the grazing exit x-ray fluorescence was tested for its applicability to x-ray
absorption near edge structure analysis of arsenic in droplet samples. The experimental results have
been compared to the findings of former analyses of the same samples using a grazing incidence
GI setup to compare the performance of both geometries. Furthermore, the investigations were
accomplished to gain a better understanding of the so called self-absorption effect, which was
observed and investigated in previous studies using a GI geometry. It was suggested that a normal
incidence-grazing-exit geometry would not suffer from self-absorption effects in x-ray absorption
fine structure XAFS analysis due to the minimized path length of the incident beam through the
sample. The results proved this assumption and in turn confirmed the occurrence of the
self-absorption effect for GI geometry. Due to its lower sensitivity it is difficult to apply the GE
geometry to XAFS analysis of trace amounts few nanograms of samples but the technique is well
suited for the analysis of small amounts of concentrated sample
Synchrotron radiation-induced total reflection X-ray fluorescence analysis
No full textSynchrotron radiation-induced total reflection X-ray fluorescence (SR-TXRF)
analysis is a high sensitive analytical technique that offers limits of detection
in the femtogram range for most elements. Besides the analytical aspect,
SR-TXRF is mainly used in combination with angle-dependent measurements
and/or X-ray absorption near-edge structure (XANES) spectroscopy to gain
additional information about the investigated sample. In this article, we
briefly discuss the fundamentals of SR-TXRF and follow with several examples
of recent research applying the above-mentioned combination of techniques
to analytical problems arising from industrial applications and
environmental research
Influence of the sample morphology on total reflection X-ray fluorescence analysis
No full textTotal reflection X-ray fluorescence analysis (TXRF) is a method for qualitative and quantitative analysis of trace elements. In general TXRF is known to allow for linear calibration typically using an internal standard for quantification. For small sample amounts (low ng region) the thin film approximation is valid neglecting absorption effects of the exciting and the detected radiation. However, for higher total amounts of samples deviations from the linear relation between fluorescence intensity and sample amount have been observed. The topic of the presented work is an investigation of the parameters influencing the absorption phenomenom. Samples with different total amounts of arsenic have been prepared to determine the upper limit of sample mass where the linear relation between fluorescence intensity and sample amount is no longer guaranteed. It was found that the relation between fluorescence intensity and sample amount is linear up to ~100 ng arsenic. A simulation model was developed to calculate the influence of the absorption effects. Even though the results of the simulations are not satisfying yet it could be shown that one of the key parameters for the absorption effect is the density of the investigated element in the dried residues
Implementing light elements detection and quantification in aluminosilicate materials using a Low-Z total-reflection X-ray fluorescence spectrometer
No full textTotal-reflection X-ray fluorescence (TXRF) is a well-established atomic spectroscopy technique used for the elemental characterization of different kinds of matrixes in several fields. Previous works demonstrated its applicability for the elemental quantification of aluminosilicates and, in particular, clays. However, one of the limits of the previously developed methods was the detection and quantification of light elements, in particular for those elements with an atomic number (Z) below 13 (Al). In the present work a new TXRF-based analytical method for the quantification of light elements in aluminosilicate materials is described, using an in-house built Low-Z TXRF spectrometer equipped with a Cr source, a multilayer monochromator, an SDD detector equipped with an ultrathin Si3N4 window and a vacuum chamber. Samples were prepared as simple slurries (dispersing 50 mg of powder into 2.5 mL of 1%-Triton X-100 water solution and adding Ag as internal standard) and 10 μL were deposited onto a quartz carrier and dried before the analysis. Light elements such as F, Na and Mg were quantified with a limit of detection of 682, 260 and 133 mg/kg, respectively. Carbon and oxygen could also be detected. The new method allowed a complete analysis of major elements in aluminosilicates from F to Fe. The method showed a good accuracy in the range of 80–120% and the results agreed with the data obtained with a commercial TXRF spectrometer (for elements >13) and WDXRF, employed as reference methods. Despite a lower precision in respect to WDXRF, in some samples the quantification of F was possible only by using the Low-Z TXRF spectrometer. Finally, the method demonstrated to be suitable for the analysis of aluminosilicates, in particular when low amounts of sample (few milligrams) are available
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