다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Wide bandgap semiconductors show superior material properties enabling potential power device operation at higher temperatures, voltages, and switching speeds than current Si technology. As a result, a new generation of power devices is being developed for power converter applications in which traditional Si power devices show limited operation. The use of these new power semiconductor devices will allow both an important improvement in the performance of existing power converters and the development of new power converters, accounting for an increase in the efficiency of the electric energy transformations and a more rational use of the electric energy. At present, SiC and GaN are the more promising semiconductor materials for these new power devices as a consequence of their outstanding properties, commercial availability of starting material, and maturity of their technological processes. This paper presents a review of recent progresses in the development of SiC- and GaN-based power semiconductor devices together with an overall view of the state of the art of this new device generation.

A Survey of Wide Bandgap Power Semiconductor Devices

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

/pdf/light-emitting-diodes-ubzde6g9qc.pdf

Light-emitting diodes

An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

Impact ionization coefficients of 4H-SiC were measured at room temperature and at elevated temperatures up to 200°C. Photomultiplication measurement was done in two complementary photodiodes to measure the multiplication factors of holes (Mp) and electrons (Mn), and ionization coefficients were extracted. Calculated breakdown voltage using the obtained ionization coefficients showed good agreement with the measured values in this study, and also in other reported PiN diodes and MOSFETs. In high-temperature measurement, breakdown voltage exhibited a positive temperature coefficient and multiplication factors showed a negative temperature coefficient. Therefore, extracted ionization coefficient has decreased which can be explained by the increase of phonon scattering. The calculated temperature dependence of breakdown voltage agreed well with the measured values not only for the diodes in this study, but also in PiN diode in other literature.

Temperature Dependence of Impact Ionization Coefficients in 4H-SiC

/pdf/silicon-carbide-volume-2-power-devices-and-sensors-6nl3knef02.pdf

Silicon Carbide: Volume 2: Power Devices and Sensors

This paper reports on the measured dc characteristics of a SiC JFET device from room temperature up to 450°C in order to evaluate the device's capability for high-temperature operation. The authors packaged SiC JFET bare die into a dedicated high-temperature package to be able to perform experiments under extremely high ambient temperatures. The experimental results show that the device can operate at 450°C, which is impossible for conventional Si devices, but the current capability of the SiC JFET diminishes with rising temperatures. For example, the saturation current becomes 20% at 450°C with respect to the value at the room temperature.

/pdf/sic-jfet-dc-characteristics-under-extremely-high-ambient-4ihhj1w34q.pdf

SiC JFET dc characteristics under extremely high ambient temperatures

Carrier lifetimes in n-type 4H-SiC epitaxial layers are limited by several factors such as deep levels, surface recombination, and recombination in the substrate. In this study, the carrier lifetime is significantly improved from 0.68 to 13.1 µs by eliminating deep levels and by improving surface passivation. Deep levels can be almost eliminated by two-step annealing as reported before, and the surface recombination can be reduced by passivating the surface with a deposited oxide annealed in nitric oxide at 1300 °C. Major recombination paths are discussed based on numerical simulation.

https://iopscience.iop.org/article/10.1143/APEX.3.121201/pdf

Enhancement of Carrier Lifetimes in n-Type 4H-SiC Epitaxial Layers by Improved Surface Passivation

We investigated the enhancement of carrier lifetime in lightly Al-doped p-type 4H-SiC epilayers (NA ≃ 2 × 1014 cm−3) by postgrowth processing. A carrier lifetime of 2.8 µs in an as-grown epilayer is increased to 5.1 µs by carbon vacancy elimination, i.e., thermal oxidation at 1400 °C for 48 h. It reaches 10 µs by subsequent hydrogen annealing at 1000 °C for 10 min. The carrier lifetime in the as-grown epilayer is also increased to 4.0 µs by only hydrogen annealing. These results suggest that, in addition to carbon vacancy, there is another lifetime killer in p-type SiC, which cannot be eliminated by thermal oxidation but can be passivated by hydrogen annealing.

https://iopscience.iop.org/article/10.7567/APEX.7.085501/pdf

Tsunenobu Kimoto

Papers

Temperature Dependence of Impact Ionization Coefficients in 4H-SiC

Silicon Carbide: Volume 2: Power Devices and Sensors

SiC JFET dc characteristics under extremely high ambient temperatures

Enhancement of Carrier Lifetimes in n-Type 4H-SiC Epitaxial Layers by Improved Surface Passivation

Enhancement of carrier lifetime in lightly Al-doped p-type 4H-SiC epitaxial layers by combination of thermal oxidation and hydrogen annealing