Yoshihiro Hashiguchi

A numerical simulation of total reflection X-ray photoelectron spectroscopy (TRXPS)

Abstract Numerical simulations of “total reflection X-ray photoelectron spectroscopy (TRXPS)” are presented. Monochromatized X-rays impinge on a specular sample with a glancing angle smaller than the critical angle of total reflection. Under this condition, the X-rays cannot penetrate deeper than the evanescent length, usually 20–40 A depending on the sample material, the wavelength of the X-rays, and the incident angle. The intensity of X-rays in the evanescent region can be as much as four times stronger than the incident X-ray intensity because of the standing-wave formation on the surface. Therefore, the photoelectron signal of atoms in the surface region is intensified. As a consequence, TRXPS is an even more powerful tool for the study of surface chemistry and physics than ordinary X-ray photoelectron spectroscopy (XPS). Moreover the signal to background ratio is improved at least twice if compared with that of the ordinary XPS because the number of inelastically scattered photoelectrons is reduced.

Crystalline Transformations in Amorphous Fe73.5Cu1Nb3Si16.5B6 Alloy

The crystallization behavior of the amorphous Fe73.5Cu1Nb3Si16.5B6 alloy has been investigated by Mossbauer spectroscopy and X-ray diffractometry. Fine crystalline grains of about 10 nm diameter are produced uniformly by annealing at 550°C for 1 hour in nitrogen atmosphere. The predominant crystalline phase is assigned to the Fe-Si alloy with DO3 structure and neither intermetallic compounds nor an amorphous phase can be recognized in the Mossbauer spectrum. The addition of 1 at% Cu to amorphous Fe-Si-B merely brings about a lowering of the crystallization temperature, while that of 3 at% Nb leads to a rise in the crystallization temperature and simultaneous formation of Fe-Si alloy and Fe3(Si, B). Their effects simultaneously influence the crystallization behavior in the amorphous Fe73.5Cu1Nb3Si16.5B6 alloy, and lead to the production of Fe-Si alloy with uniform ultrafine grains. Annealing at 720°C for 1 hour gives rise to the growth of the fine grains and the formation of Fe3(Si, B).

Sample current maximum at the critical angle of x‐ray total reflection

The x‐ray photoemitted electron intensity and sample current of a GaAs wafer are measured at 2 and 3 keV excitation photon energies while varying the glancing angle of the incident x rays. It is found that the sample current and the x‐ray photoemitted electron intensity have similar behavior with respect to the glancing angle. The sample current as well as the photoemission intensity have a maximum at the critical angle of the x‐ray total reflection. This is the first report of the observation of the existence of a sample current maximum at the critical angle of x‐ray total reflection.

Relation between Cu L X-Ray and Cu 2p Photoelectron in YBa2Cu3Ox

X-ray emission spectroscopy (XES) is applied to the study of the electronic structure o f Cu in YBa2Cu3Ox superconductors. It is shown that the Cu Lβ/Lα intensity ratio of the orthorhombic sample is about 4% higher than that of the tetragonal sample. The origin of this difference can be discussed consistently using Cu 2p X-ray photoelectron spectroscopy (XPS) spectra, indicating that the effect of charge transfer from O 2p to the Cu 3d hole is comparatively small for the orthorhombic sample in generation of Cu 2p hole. It is confirmed that the probability of |2p3d10L> and |2p3d10L2 > in the intermediate state for the tetragonal becomes higher in L line X-ray emission than that for the orthorhombic. As the result, the population of MV for the orthorhombic becomes low and only the intensity of Lα line is decreased.

Current-Path Observation in Low-Dose SIMOX(Separation by Implanted Oxygen) Buried-SiO2 Layer.

Current paths in the buried- SiO2 layer of low-dose SIMOX (Separation by IMplanted OXygen) wafers are observed directly by micro-beam techniques both in plan and sectional views based on Cu-plated indications. Large-area current paths display particle traces on the surface-Si layer immediately above the current path. Higher annealing temperatures (≥1330° C) decrease micro-roughness along the buried- SiO2 front/back boundaries and reduce current-path density.

Photoirradiation‐charge compensation for secondary ion mass spectrometers analysis of semiconductors

For secondary ion mass spectrometry (SIMS) analysis a photoirradiation‐charge compensation technique has proven to be very effective and useful in the analysis of semiconductor samples. The mechanism of charge compensation was also studied. Monochromatized visible light was applied to the SIMS analysis of narrow band gap semiconductors. UV synchrotron radiation was used to irradiate a wide band gap semiconductor studied using ion induced Auger electron spectroscopy as well as SIMS. It was confirmed that photoirradiation at a photon energy greater than the band gap of the sample induces photoconductivity through electron–hole pair creation at the top surface.

DEPTH PROFILING OF HG1-XCDXTE BY SECONDARY ION MASS SPECTROMETRY : DETECTING CSX+ WITH CS+ ION BEAM

Hg1-x Cdx Te (MCT) multilayers grown by photoassisted metal organic chemical vapor deposition (MOCVD) utilizing the interdiffused multilayer process (IMP) have been investigated by secondary ion mass spectrometry (SIMS). The SIMS measurement used a primary ion beam of Cs and the detected secondary ions were of the form CsX+ (X=Cd, Te and Hg). The secondary ion intensity of CsHg+ was higher than that of Hg+ by about two orders of magnitude. CsX+ detection was shown to achieve excellent linearity with the content of Hg in a series of Hg1-x Cdx Te samples (x=0, 0.2, 0.3, 0.375 and 1.0). CsX+ detection by SIMS was proven to be a very useful technique for the evaluation of the thin multilayers in the MCT samples whose layers have 180 nm to 360 nm in thickness.