A thin diffusion barrier was self-formed by annealing at an interface between a Cu-Mn alloy film and SiO2 substrate. The growth of the layer followed logarithmic rate law, which represents field-enhanced mechanism in early stage self-limiting behavior late stage. stable 450 °C for 100 h 600 10 h. diffusivity estimated from morphology change found to be smaller than grain-boundary bulk Cu.

Time-dependent dielectric breakdown (TDDB) measurement of MOS capacitors on an n-type 4 ° off-axis 4H-SiC(0001) wafer free from step-bunching showed specific in the Weibull distribution plots. By observing as-grown SiC-epi surface, two kinds epitaxial surface defect, Trapezoid-shape and Bar-shape defects, were confirmed with confocal microscope. Charge to (Qbd) including upstream line these defects is almost same value as that a Wear-out region. On other hand, gate oxide occurred at...

A self-forming diffusion barrier (SFB) layer was formed at Cu–Mn/SiO2 interface. Spatial variation of the chemical composition and valence state elements in SFB investigated a subnanometer resolution using electron energy loss spectroscopy transmission microscopy. The found to have layered structure with graded compositions nanocrystalline MnO amorphous MnSiO3. Mn be +2 gradually increased +3 MnSiO3 layer. reported dielectric constant could explained by observed microstructure.

The surface morphology and lattice defect structures in the subsurface regions of 4H-SiC wafers introduced during chemo-mechanical polishing (CMP) were studied by scanning electron microscopy transmission microscopy. It is known that local damage consisting high-density defects current CMP, however, optical showed was very flat clean without any presence defects. Specifically, this study focused on detailed analysis such structures. locally consisted nano-scale scratches, basal-plane...

Damaged layers, which are introduced during chemo-mechanical polishing (CMP) underneath the 4°off-cut 4H-SiC wafer surface and cause defects formations after epitaxial films growth, investigated by scanning electron microscopy (SEM) transmission (TEM). SEM observations show presence of small scratches on surfaces CMP process. The widths such submicron meters, thus it is hard to detect them optical microscopy. TEM that high-density regions dislocation loops exist below much wider than...

Surface defects with a scratch-like appearance are often observed locally on 4H-SiC wafers after epitaxial film (epi-film) growth. Since optical microscopy has only revealed very flat surface chemo-mechanical polishing (CMP) and before epi-film growth, the origins of these have remained unknown. Therefore, we investigated generation mechanism such by synchrotron Berg–Barrett X-ray topography. Although highly surfaces microscopy, found that damaged regions comprising lattice introduced during...

Surface roughening regions running like scratches are often observed locally after epitaxy film grown on a very flat 4H-SiC wafer surfaces. We investigated generation mechanism of such surface by using X-ray topography and confocal optical microscopy. found that lattice defects were introduced during CMP at local regions, those cannot be recognized microscopy, since can observed. By H 2 etching which is preprocess growth, almost etched off, but rough consists pits step bunching appear...

Lanthanum calcium oxoborate LaCa4O(BO3)3 (LaCOB) bulk single crystals were grown by the Czochralski technique. The have almost constant transmittances between 320 and 2500 nm. relationship growth habit crystallographic abc - rectangular XYZ axes was clarified. Some dielectric piezoelectric constants as well elastic compliance of LaCOB evaluated. surface acoustic wave (SAW) pseudo-SAW (PSAW) parameters also measured. For SAW, largest electromechanical coupling coefficient approximately 0.26%...

We measured cathodoluminescence (CL) spectra of SiO2 films grown on 4H-SiC wafers and found that for an acceleration voltage 5 kV, CL peaks at 460 490 nm, assigned to oxygen vacancy centers (OVCs), become weak by post-oxidation annealing in N2O ambient 1300 °C whereas the peak around 580 related Si-N bonding structures, becomes intense. Furthermore, N-Si3 configurations x-ray photoelectron spectroscopy (XPS) was observed SiO2/SiC interface only samples annealed ambient. These results suggest...

The reliability of the gate oxide on large-area surface defects (trapezoid-shaped and obtuse triangular defects) in 4H-SiC epitaxial wafers is discussed. Time-dependent dielectric breakdown measurements revealed that a reduction charge-to-breakdown ( Q bd ) occurred at MOS capacitor including downstream line those defects. deterioration was same level trapezoid-shaped A cross-sectional transmission electron microscope (TEM) image simulation electric field distribution for structure indicated...

We have found undiscovered defects on a 4H-SiC epitaxial layer, the shape of which resembles scraper in images taken by confocal differential interference contrast optical microscopy. The surface morphological structure and formation mechanism scraper-shaped were investigated atomic force microscopy grazing incidence monochromatic synchrotron X-ray topography, respectively. consisting asperity caused migration interfacial dislocations. evaluation thermal oxide reliability...

The thermal diffusion of germanium and oxygen atoms in HfO2/GeO2/Ge gate stacks was comprehensively evaluated by x-ray photoelectron spectroscopy secondary ion mass spectrometry combined with an isotopic labeling technique. It found that 18O-tracers composing the GeO2 underlayers diffuse within HfO2 overlayers based on Fick's law low activation energy about 0.5 eV. Although out-diffusion through also proceeded at temperatures around 200 °C, diffusing preferentially segregated surfaces,...

The Integrated Evaluation Platform for SiC wafers and epitaxial films is established provide TDDB reliability data such as Q bd . Accumulated numerous derived from the platform shows three discrete universal distributions (D1>D2>D3) mainly affected by step bunching. On fairly flat surface, locally spreading step-bunching area formation caused scratches on CMP surface. contains large number of lines, which correspond to trapezoid-shape defects, stretching in a low along scratches. Only...

We used Fourier transform infrared (FT-IR) spectroscopy to characterize silicon dioxide (SiO2) films on a 4H-SiC(0001) Si face. found that the peak frequency of transverse optical (TO) phonon in SiO2 grown 4H-SiC substrate agrees well with substrate, whereas longitudinal (LO) is red-shifted by approximately 50 cm−1 relative substrate. concluded this red-shift LO mainly caused change inhomogeneity due decrease density films. Furthermore, cathodoluminescence (CL) results indicated channel...

Abstract To clarify the behavior of AlGaN in 20 nm wide Ga-rich current pathways an n-AlGaN layer, which assists carrier localization AlGaN-based light-emitting diodes, we performed a detailed analysis using n-Al 0.7 Ga 0.3 N layer on AlN with dense macrosteps 1.0° miscut sapphire substrate. Energy-dispersive X-ray spectra, obtained cross-sectional scanning transmission electron microscopy calibrated by Rutherford backscattering and cathodoluminescence indicated that mole fraction was nearly...

On 4 H -SiC Si-face substrates after 2 etching, the defect with “line” feature parallel to a step as “bunched-step line” was observed. Using X-ray topography and KOH we confirmed that bunched-step line originated from basal plane dislocation (BPD). Use of substrate lowest BPD density will be effective reduce would affect oxide layer reliability on an epitaxial layer. However, more detail investigation needs classify become starting point line.

Ga-rich zones created along macrosteps in n-AlGaN plausibly function as electron pathways of AlGaN-based deep-ultraviolet (DUV) LEDs fabricated on AlN templates using 1.0°-miscut c(0001) sapphire substrates toward the m[1-100] axis. This work was performed to clarify mole fractions (xAl) zones. xAl ≃ (7/12, 6/12, and 5/12) observed AlαGa1−αN (α 0.63, 0.55, 0.43, respectively) by method proposed our previous article which we showed that Al8/12Ga4/12N were Al0.7Ga0.3N. obtained from an...

When nonflat AlxGa1−xN quantum wells (QWs) for producing 285 nm light emitting diodes (LEDs) were fabricated on n-AlGaN AlN templates with dense macrosteps c(0001) sapphire substrates a 1.0° miscut relative to the m[1–100] axis, composite electroluminescence (EL) spectra from both inclined and terrace zones in QWs (x∼ 1/3) generated owing compositional thickness modulations. The shoulder or main peaks EL tended locate at fixed discrete wavelengths of ∼287, ∼292, ∼296 12 nonuniform LED wafers...

Abstract Energy-dispersive X-ray signals calibrated by Rutherford backscattering indicated the generation of Al 13/24 Ga 11/24 N in Ga-rich stripes a nonflat 0.58 0.42 layer. Also, CL peak wavelengths ∼259 and 272 nm also showed 15/24 9/24 Al-rich zones stripes, respectively. The wavelength strong at ∼246 nm, which was observed from 0.7 0.3 layer our previous study, is considered to correspond near-band-emission 17/24 7/24 N. In particular, stronger reproducibility metastable confirmed,...