Probing the effect of point defects on the leakage blocking capability of Al0.1Ga0.9N/Si structures using a monoenergetic positron beam

Vacancy-type defects in Al0.1Ga0.9N were probed using a monoenergetic positron beam. Al0.1Ga0.9N layers with different carbon doping concentrations ([C] = 5 x 10(17) -8 x 10(19) cm(-3)) were grown on Si substrates by metalorganic vapor phase epitaxy. The major defect species in Al0.1Ga0.9N was determined to be a cation vacancy (or cation vacancies) coupled with nitrogen vacancies and/or with carbon atoms at nitrogen sites (C(N)s). The charge state of the vacancies was positive because of the electron transfer from the defects to C-N-related acceptors. The defect charge state was changed from positive to neutral when the sample was illuminated with photon energy above 1.8 eV, and this energy range agreed with the yellow and blue luminescence. For the sample with high [C], the charge transition of the vacancies under illumination was found to be suppressed, which was attributed to the trapping of emitted electrons by C-N-related acceptors. With increasing [C], the breakdown voltage under the reverse bias condition increased. This was explained by the trapping of the injected electrons by the positively charged vacancies and C-N-related acceptors

Recent Progress in Gas Barrier Thin Film Coatings on PET Bottles in Food and Beverage Applications

This article presents a short history and the recent advancement of the development of chemical vapor deposition technologies to form thin film gas barrier coatings on PET bottles and other plastic containers in food and beverage containers. Among different gas barrier enhancement technologies, coating can show unique performance where relatively high gas barrier enhancement is possible to various gas permeants. In this article, technologically common and different points of the current thin film coating methods in this field are summarized. This article also refers to recent market situations and technological challenges in the Japanese market

Improvements in quantum efficiency of excitonic emissions in ZnO epilayers by the elimination of point defects

科研費報告書収録論文(課題番号:18350092/研究代表者:大友明/高効率酸化亜鉛系青色・紫外発光素子の開発

Future directions of positron annihilation spectroscopy in low-k dielectric films

Positronium Annihilation Lifetime Spectroscopy (PALS) has become recognized in the microelectronics industry as one of only several methods capable of quantitatively characterizing engineered nanopores in next-generation (k < 2.2) interlayer dielectric (ILD) thin films. Successes and shortcomings of PALS to date will be assessed and compared with other methods of porosimetry such as ellipsometric and X-ray porosimetries (EP and XRP). A major theme in future low-k research focuses on the ability to integrate porous ILD's into chip fabrication; the vulnerability of porous dielectrics to etching, ashing, and chemical-mechanical polishing in process integration is delaying the introduction of ultra-low-k films. As device size approaches 45 nm the need to probe very small (sub-nanometer), semi-isolated pores beneath thin diffusion barriers is even more challenging. Depth-profiled PALS with its ability to determine a quantitative pore interconnection length and easily resolve 0.3 nm pores beneath diffusion barriers or in trench-patterned dielectrics should have a bright future in porous ILD research. The ability of PALS (and PAS in general) to deduce evolution and growth of pores with porosity should find broad applicability in the emerging field of high performance materials with strategically engineered nanopores. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56172/1/3796_ftp.pd

Simple way of finding Ba to Si deposition rate ratios for high photoresponsivity in BaSi2 films by Raman spectroscopy

Since the photoresponsivity of BaSi2 is sensitive to a Ba-to-Si deposition rate ratio (R Ba/R Si), there is a need to determine the optimum value of R Ba/R Si. We grew 0.5 μm thick BaSi2 films with R Ba/R Si varied from 1.1–3.6 at 580 °C and 0.4–4.7 at 650 °C. The photoresponsivity reached a maximum at R Ba/R Si = 2.2 and 1.2, respectively. Raman spectroscopy revealed that the crystalline quality of BaSi2 became better with decreasing R Ba/R Si. However, as R Ba/R Si decreased further beyond these values, excess Si precipitated, showing that the optimum value of R Ba/R Si should be as small as possible without causing Si precipitates to form

Finite temperature effects on the structural stability of Si-doped HfO2_{2} using first-principles calculations

The structural stabilities of the monoclinic and tetragonal phases of Si-doped HfO$_{2}$ at finite temperatures were analyzed using a computational scheme to assess the effects of impurity doping. The finite temperature effects considered in this work represented lattice vibration and impurity configuration effects. The results show that 6% Si doping stabilizes the tetragonal phase at room temperature, although a higher concentration of Si is required to stabilize the tetragonal phase at zero temperature. These data indicate that lattice vibration and impurity configuration effects are important factors determining structural stability at finite temperatures.Comment: 5 pages, 3 figure