A5089038506- Semiconductor materials and devices
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and interfaces
- Electronic and Structural Properties of Oxides
- Integrated Circuits and Semiconductor Failure Analysis
- Ion-surface interactions and analysis
- Silicon Carbide Semiconductor Technologies
- Silicon and Solar Cell Technologies
- Metal and Thin Film Mechanics
- Ga2O3 and related materials
- Silicon Nanostructures and Photoluminescence
- Copper Interconnects and Reliability
- Advancements in Semiconductor Devices and Circuit Design
- Molecular spectroscopy and chirality
- Thin-Film Transistor Technologies
- Asymmetric Synthesis and Catalysis
- GaN-based semiconductor devices and materials
- Analytical Chemistry and Chromatography
- Liquid Crystal Research Advancements
- Organometallic Complex Synthesis and Catalysis
- Ferroelectric and Negative Capacitance Devices
- Chemical Synthesis and Reactions
- Surfactants and Colloidal Systems
- Asymmetric Hydrogenation and Catalysis
- Catalytic Processes in Materials Science
Tokyo City University
2015-2025
Tohoku University
2017
Lead City University
2013-2014
Sahmyook University
2013-2014
Tokyo Institute of Technology
1989-2013
Musashi University
2001-2010
Tokyo Denki University
2010
Saitama University
1987-2007
Vision Engineering (Italy)
2007
KU Leuven
2003
High-resolution x-ray photoelectron spectroscopy (XPS) at 6 keV photon energy has been realized utilizing high-flux-density x rays from the third generation high-energy synchrotron radiation facility, SPring-8. The method applied to analysis of high-k HfO2/interlayer/Si complementary metal–oxide–semiconductor gate-dielectric structures. With high resolution and throughput our system, chemical-state differences were observed in Si 1s, Hf 3d, O 1s peaks for as-deposited annealed samples....
Mechanical strain/stress and crystal defects are produced in extremely thin wafers (thickness ~10 μm) of 3D-LSIs not only during wafer thinning, but also after bonding using fine-pitch, high-density microbumps curing. Furthermore, the metal through-Si via (TSV) microbump becomes cause contamination, induces (due to difference co-efficient thermal expansion (CTE) between Si metal) thinned substrate. X-ray photoelectron spectroscopy (XPS) results showed that quality is highly deteriorated...
Abstract GeO2 prepared via thermal oxidation at ambient pressure is known to be of poor-quality owing numerous defects and high interface states. Several methods for fabricating high-quality films been reported, such as applying pressure, but all them present challenges. Therefore, a simpler fabrication method required. In this study, we attempted reduce states in GeO2/Ge atmospheric-pressure using ultraviolet–ozone (UVO) treatment. Measurement results indicated that UVO treatment can the...
The valence-band and the O $2s$ core-level spectra of ultrathin (about 1 nm) ${\mathrm{SiO}}_{2}$ layers [which are formed at initial stages oxidation hydrogen-terminated Si(100) substrates] were measured by high-resolution x-ray photoelectron spectroscopy. energy difference between valence band core level was found to be greater than that for bulk ${\mathrm{SiO}}_{2}.$ A first-principle molecular-orbital calculation performed on ${\mathrm{Si}}_{2}{\mathrm{O}}_{7}{\mathrm{H}}_{6}$ clusters...
Abstract A summary of the workshop entitled ‘Angle‐Resolved XPS: The Current Status and Future Prospects for Angle‐resolved XPS Nano Subnano Films’ is given, which was held at Riviera Maya, Mexico, 26–30 March 2007, under main sponsorship International Union Vacuum Science, Technique Applications (IUVSTA). X‐ray photoelectron spectroscopy (ARXPS) can provide detailed chemical as well depth profile information about near‐surface composition materials thin films. This to review present status...
Wafer thinning and formation of through-Si via (TSV) metal microbump are key processes in 3D LSI fabrication. However, it might introduce mechanical stress crystal defects thinned wafers. In addition, Cu for TSV contamination Si substrate. Then the impact substrate has been investigated. The remnant left after wafer was evaluated by micro-Raman spectroscopy (¿RS) XPS. It found that remained back surface a part this appeared such C-t method. carrier generation lifetime degraded diffused into...
Abstract The presence of hydrogen-incorporated defects in silicon nitride (SiN) films has been reported to degrade device properties, such as NAND flash memory. Therefore, controlling the amount hydrogen SiN achieve high reliability is important. This study investigated desorption using plasma treatment reduce films. Secondary ion mass spectrometry measurements showed that concentration does not change significantly pre- and post-treatment. However, trap levels determined Poole–Frenkel...
Interface dipole modulation (IDM) has predominantly used TiO2 as the IDM layer, and changes in valence state of critically affect device operation. This study demonstrates use SnOx instead TiOx for elucidates underlying mechanism detail. Metal–oxide–semiconductor capacitors with an Al2O3/atomic-layer-thick SnOx/SiO2 stacked structure were fabricated analyzed. Capacitance–voltage measurements revealed that polarity interface layer changed depending on gate bias. Hard x-ray photoelectron...
High-resolution surface tension measurements have been carried out on the free-standing films of more than 30 selected liquid-crystal compounds in their smectic phases. Surface (γ) values falling into major categories 27, 24, 21, 13, and 11.5 dyn/cm obtained. The dependence γ specific terminal groups or molecular structures will be discussed. Our results provide important information about origin tension.
The chemical bonding states of boron (B) in shallow P+/N junctions on Si substrates were studied by soft x-ray photoelectron spectroscopy (SXPES). This study revealed three B embedded bulk Si. concentration profiles successfully determined combining SXPES with step-by-step etching substrates. thus good agreement those secondary ion mass spectroscopy. holes also Hall measurements the having lowest binding energy found to agree well holes. Therefore, can be assigned as activated and middle...
X-ray photoelectron spectroscopic evaluation of the ${\mathrm{SiO}}_{2}/\mathrm{S}\mathrm{i}(111)$ interface reveals that valence-band offset differs by about 0.19 eV between two types atomic structures contain Si atoms in different intermediate-oxidation states. The difference is reproduced a first-principles molecular orbital calculation for model clusters $({\mathrm{Si}}_{17}{\mathrm{O}}_{4}{\mathrm{H}}_{36}$ and ${\mathrm{Si}}_{17}{\mathrm{O}}_{3}{\mathrm{H}}_{36})$ structures. It...
Abstract Two new series of ferroelectric liquid crystals with a fluorinated asymmetric frame were synthesized by utilizing optically active S-(-)-2-fluoroalkanols or S-(-)-2-fluoroalkanoic acids, and their mesomorphic physical properties studied. 5-Alkyl-2-[p-(2-fluoroalkyloxy)phenyl]pyrimidines (5, n ≧ 6, m = 12) exhibited enantiotropic chiral smectic C phase, spontaneous polarizations more than 34nC/cm2 (except for 4). The values response time short (on the order 10 μ sec) found to be...
Thermally oxidized SiO 2 /Si and GeO /Ge are difficult to form very thin oxide films by atomic layer deposition (ALD) due the chemical inertness of film surface. In this study, effect surface modification insulating UV-Ozone (UVO) method on ALD was investigated with aim controlling thickness producing a uniform film. The results show that UVO treatment can deposit layer-thick or without delay. This may be formation dangling bonds surface, which improves reactivity between precursor during...
We established the number of Si 2p photoelectrons emanating from a Si(100) substrate covered with silicon–oxide film as function azimuthal and polar angles using oxide thickness parameter. The elastic inelastic scattering cross sections in silicon were deduced by reproducing experimental results Monte Carlo simulation for path oxide. Based on simulation, we found that could effectively be neglected several specific directions. also an emitting direction different to these directions is...
Abstract New ferroelectric liquid crystals with a fluorinated asymmetric frame were synthesized utilizing optically active S-(-)-2-fluoroalkanols prepared from R-(+)-1,2-epoxyalkanes pyridinium poly(hydrogen fluoride), and their mesomorphic physical properties (phase behavior, spontaneous polarization, response time) studied. The biphenyl-phenyl derivatives of three-ring systems exhibited enantiotropic chiral smectic C phase in broad temperature range (108°C-185°C). phenyl benzoate two-ring...
Abstract A new method for the combination analysis of high‐resolution Rutherford backscattering spectroscopy (HRBS) and angle‐resolved X‐ray photoelectron (AR‐XPS) is proposed accurate depth profiling chemical states. In this method, attenuation lengths (ALs) photoelectrons are first determined so that AR‐XPS result consistent with HRBS result. Depth states then performed in using composition‐depth profiles obtained by as constrained conditions. This successfully applied to Hf‐based gate...