Silicate Formation at the Interface of high-k dielectrics and Si(001) Surfaces

2006 ◽  
Vol 917 ◽  
Author(s):  
Dieter Schmeisser ◽  
F. Zheng ◽  
F.J. Himpsel ◽  
H.J. Engelmann
Keyword(s):  
High Sensitivity ◽  
Fluorescence Yield ◽  
Gate Stacks ◽  
Total Electron ◽  
Silicate Formation ◽  
High K ◽  
Total Fluorescence ◽  
Characteristic Features ◽  
X Ray Absorption

AbstractThe composition and chemical bonding of the first atoms across the interface between Si(001) and the dielectric determine the quality of dielectric gate stacks. An analysis of that hidden interface is a challenge as it requires both, high sensitivity and elemental and chemical state information. We used SR based photoelectron spectroscopies and, in particular, X-ray absorption spectroscopy in total electron yield and total fluorescence yield at the Si2p and the O1s edges to address that issue. We report on results of Hf-oxide prepared by ALD and compare to Pr2O3 / Si(001), and compare the two to the SiO2 / Si(001) system as a reference. For both, Hf-oxide and Pr-oxide thin films we find evidence for the silicate formation at the interface as derived from the characteristic features at the Si2p and the O1s edges.

Silicon L2, 3-Edge Xanes Study of Platinum Silicide Thin Films

1996 ◽  
Vol 441 ◽  
Author(s):  
S. J. Naftel ◽  
T. K. Sham ◽  
S. R. Das ◽  
D.-X. Xu
Keyword(s):  
Fluorescence Yield ◽  
Detection Methods ◽  
Sampling Depth ◽  
Total Electron ◽  
Edge Structure ◽  
X Ray ◽  
Platinum Silicide ◽  
Depth Difference ◽  
Total Fluorescence ◽  
X Ray Absorption

AbstractPlatinum silicide films, with a typical thickness of several hundred Å, prepared on n-type Si(100) wafers by UHV mnagnetron sputter deposition followed by rapid thermal annealing, have been studied by Si L2,3-edge X-ray absorption near edge structure (XANES) using both total electron and total fluorescence yield detection. Samples of various annealing times were studied. XANES provides information on the electronic structure and morphology of the samples. By utilizing the sampling depth difference between the two detection methods, we can clearly see XANES data from each layer (eg. surface oxide, silicide) in the sample and can estimate the thickness of the oxide layer.

scholarly journals A zone-plate-based two-color spectrometer for indirect X-ray absorption spectroscopy

2019 ◽  
Vol 26 (4) ◽  
pp. 1266-1271 ◽  
Author(s):  
Florian Döring ◽  
Marcel Risch ◽  
Benedikt Rösner ◽  
Martin Beye ◽  
Philipp Busse ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Fresnel Zone ◽  
Decay Channel ◽  
Chemical Properties ◽  
Fluorescence Yield ◽  
Complex Materials ◽  
X Ray ◽  
Total Fluorescence ◽  
X Ray Absorption

X-ray absorption spectroscopy (XAS) is a powerful element-specific technique that allows the study of structural and chemical properties of matter. Often an indirect method is used to access the X-ray absorption (XA). This work demonstrates a new XAS implementation that is based on off-axis transmission Fresnel zone plates to obtain the XA spectrum of La0.6Sr0.4MnO3 by analysis of three emission lines simultaneously at the detector, namely the O 2p–1s, Mn 3s–2p and Mn 3d–2p transitions. This scheme allows the simultaneous measurement of an integrated total fluorescence yield and the partial fluorescence yields (PFY) of the Mn 3s–2p and Mn 3d–2p transitions when scanning the Mn L-edge. In addition to this, the reduction in O fluorescence provides another measure for absorption often referred to as the inverse partial fluorescence yield (IPFY). Among these different methods to measure XA, the Mn 3s PFY and IPFY deviate the least from the true XA spectra due to the negligible influence of selection rules on the decay channel. Other advantages of this new scheme are the potential to strongly increase the efficiency and throughput compared with similar measurements using conventional gratings and to increase the signal-to-noise of the XA spectra as compared with a photodiode. The ability to record undistorted bulk XA spectra at high flux is crucial for future in situ spectroscopy experiments on complex materials.

On the origin of dips in total fluorescence yield X-ray absorption spectra: Partial and inverse partial fluorescence yield at the L-edge of cobalt aqueous solution

2012 ◽  
Vol 546 ◽  
pp. 164-167 ◽  
Author(s):  
Mikhail A. Soldatov ◽  
Kathrin M. Lange ◽  
Malte D. Gotz ◽  
Nicholas Engel ◽  
Ronny Golnak ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Absorption Spectra ◽  
Fluorescence Yield ◽  
X Ray ◽  
Total Fluorescence ◽  
X Ray Absorption

X-Ray Absorption Studies of Titanium Silicide Formation at the Interface of Ti Deposited on Si

1989 ◽  
Vol 159 ◽  
Author(s):  
D.B. Aldrich ◽  
R.W. Fiordalice ◽  
H. Jeon ◽  
Q. Islam ◽  
R.J. Nemanich ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Film Structure ◽  
Titanium Silicide ◽  
Vacuum Furnace ◽  
Total Electron Yield ◽  
Total Electron ◽  
X Ray ◽  
Absorption Studies ◽  
Metallic Bonding ◽  
X Ray Absorption

ABSTRACTNear edge X-ray absorption spectra (XANES) have been obtained from the Ti K-edge for several series of titanium silicide samples produced by different techniques. Samples were fabricated by depositing Ti on silicon wafers and subsequently annealing them up to temperatures from 100°C to 900°C in UHV, vacuum furnace, or in a Rapid Thermal Annealing system. Measurements were done in the fluorescence and total electron yield modes. The XANES measurements were correlated with Raman scattering measurements. The XANES data of several reference compounds were obtained, and the data showed a high sensitivity to changes in the film structure. Ti metallic bonding and Ti-Si bonds can be distinguished and their evolution as a function of annealing is related to previous results. For the samples with increased impurities, Ti regions were stable at higher temperatures. The XANES spectra of samples annealed under N2 indicate the formation of a surface nitride.

X-Ray Absorption Fine Structure (Xafs) Studies Of Cobalt Silicide Thin Films

1998 ◽  
Vol 524 ◽  
Author(s):  
S. J. Naftel ◽  
I Coulthard ◽  
Y. Hu ◽  
T. K. Sham ◽  
M. Zinke-Allmang
Keyword(s):  
Thin Films ◽  
Fine Structure ◽  
Fluorescence Yield ◽  
Sputter Deposition ◽  
Cobalt Silicide ◽  
Total Electron ◽  
X Ray ◽  
Absorption Fine ◽  
Fine Structures ◽  
X Ray Absorption

ABSTRACTCobalt silicide thin films, prepared on Si(100) wafers, have been studied by X-ray absorption near edge structures (XANES) at the Si K-, L2,3 and Co K-edges utilizing both total electron (TEY) and fluorescence yield (FLY) detection as well as extended X-ray absorption fine structure (EXAFS) at the Co K-edge. Samples made using DC sputter deposition on clean Si surfaces and MBE were studied along with a bulk CoSi2 sample. XANES and EXAFS provide information about the electronic structure and morphology of the films. It was found that the films studied have essentially the same structure as bulk CoSi2. Both the spectroscopy and materials characterization aspects of XAFS (X-ray absorption fine structures) are discussed.

Direction of ionospheric structures in LOFAR calibration data

2020 ◽  
Author(s):  
Katarzyna Budzińska ◽  
Maaijke Mevius ◽  
Marcin Grzesiak ◽  
Mariusz Pożoga ◽  
Barbara Matyjasiak ◽  
...  
Keyword(s):  
Low Frequency ◽  
High Sensitivity ◽  
Electromagnetic Signal ◽  
Electron Content ◽  
Calibration Data ◽  
Total Electron ◽  
Medium Scale ◽  
Frequency Regime ◽  
Scale Structures

<pre>The Low Frequency Array (LOFAR) interferometer is a radio telescope network that provides the radio astronomical observations with the highest up-to-date sensitivity in the frequency regime between 10 and 240 MHz. As these frequencies approach the ionospheric plasma frequency, ionospheric perturbation of propagating electromagnetic signal is the main environmental factor affecting the quality of observations. Removal of ionospheric influence is a part of routinely conducted data calibration, resulting in high sensitivity differential Total Electron Content (dTEC) values between LOFAR stations. In this study we present a method for medium scale ionospheric structures detection applied to interferometric data obtained from calibration solutions of one of the key LOFAR projects- the Epoch of Reionization. Each observation spans 110-250 MHz of frequency range and lasts 6-8 hours during winter nighttime. Due to operating frequency and sensitivity of interferometric data, studies conducted with LOFAR can complement GNSS research with medium scale structures.</pre>

Depth-dependent atomic valence determination by synchrotron techniques

2018 ◽  
Vol 25 (6) ◽  
pp. 1711-1718
Author(s):  
Robbyn Trappen ◽  
Jinling Zhou ◽  
Vu Thanh Tra ◽  
Chih-Yeh Huang ◽  
Shuai Dong ◽  
...  
Keyword(s):  
Weighted Average ◽  
Fluorescence Yield ◽  
Layer By Layer ◽  
Total Electron ◽  
Model Hamiltonian ◽  
Properties Of Materials ◽  
X Ray Absorption ◽  
Non Destructive ◽  
Atomic Valence

The properties of many materials can be strongly affected by the atomic valence of the contained individual elements, which may vary at surfaces and other interfaces. These variations can have a critical impact on material performance in applications. A non-destructive method for the determination of layer-by-layer atomic valence as a function of material thickness is presented for La0.7Sr0.3MnO3 (LSMO) thin films. The method utilizes a combination of bulk- and surface-sensitive X-ray absorption spectroscopy (XAS) detection modes; here, the modes are fluorescence yield and surface-sensitive total electron yield. The weighted-average Mn atomic valence as measured from the two modes are simultaneously fitted using a model for the layer-by-layer variation of valence based on theoretical model Hamiltonian calculations. Using this model, the Mn valence profile in LSMO thin film is extracted and the valence within each layer is determined to within an uncertainty of a few percent. The approach presented here could be used to study the layer-dependent valence in other systems or extended to different properties of materials such as magnetism.

Determination of the Anomalous Scattering Factors in the Soft-X-ray Range using Diffraction from a Multilayer

1998 ◽  
Vol 31 (5) ◽  
pp. 700-707 ◽  
Author(s):  
L. Sève ◽  
J. M. Tonnerre ◽  
D. Raoux
Keyword(s):  
Fluorescence Yield ◽  
Bragg Diffraction ◽  
Anomalous Scattering ◽  
Total Electron Yield ◽  
Total Electron ◽  
X Ray ◽  
Scattering Factor ◽  
X Ray Absorption ◽  
Kronig Relation

Bragg diffraction from an Ag/Ni multilayer was used to determine independently both the real and imaginary parts of the anomalous scattering factor (ASF) around the NiLIIIandLIIedges in the soft-X-ray range. Huge resonant variations were observed with f'' reaching 55\,r_o and f' decreasing to −63 r_o at the NiLIIIedge. The independent measurements of f' and f'' are tested for coherency using the Kramers–Kronig relation. The f'' values are also compared with those derived from X-ray absorption methods such as total electron yield and fluorescence yield measurements.

Sign in / Sign up

Export Citation Format

Share Document