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.

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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

Homoepitaxial growth of 4H-SiC could be achieved at 1500°C on off-oriented 4H-SiC{0001} substrates by means of a vapor phase epitaxial method. Grown layers showed specular smooth surfaces on both (0001)Si and (000)C faces. Doping of Ga during crystal growth was carried out and photoluminescence of grown layers was studied. Bluish-violet photoluminescence due to donor(N)-acceptor(Ga) pair recombination and recombination of a free electron with a hole at a Ga acceptor was observed. The emission attributed to the latter recombination process became dominant at high temperatures above 100 K. The luminescence of Ga-doped 4H-SiC was not quenched up to temperatures as high as 150 K, whereas the luminescence intensity of Al-doped 6H-SiC and 4H-SiC started to decrease at 70 and 85 K, respectively.

https://iopscience.iop.org/article/10.1143/JJAP.32.1045/pdf

Step-Controlled Epitaxial Growth of 4H-SiC and Doping of Ga as a Blue Luminescent Center

Characteristics of p-n junction fabricated by aluminum-ion (Al/sup +/) or boron-ion (B/sup +/) implantation and high-dose Al/sup +/-implantation into 4H-SiC (0001) have been investigated. By the combination of high-dose (4/spl times/10/sup 15/ cm/sup -2/) Al/sup +/ implantation at 500/spl deg/C and subsequent annealing at 1700/spl deg/C, a minimum sheet resistance of 3.6 k/spl Omega///spl square/ (p-type) has been obtained. Three types of diodes with planar structure were fabricated by employing Al+ or B+ implantation. B/sup +/-implanted diodes have shown higher breakdown voltages than Al/sup +/-implanted diodes. A SiC p-n diode fabricated by deep B+ implantation has exhibited a high breakdown voltage of 2900 V with a low on-resistance of 8.0 m/spl Omega/cm/sup 2/ at room temperature. The diodes fabricated in this study showed positive temperature coefficients of breakdown voltage, meaning avalanche breakdown. The avalanche breakdown is discussed with observation of luminescence.

/pdf/avalanche-phenomena-in-4h-sic-p-n-diodes-fabricated-by-1b31rz7g1c.pdf

Avalanche phenomena in 4H-SiC p-n diodes fabricated by aluminum or boron implantation

This paper discusses surface mechanisms in homoepitaxial growth of α-SiC {0001}vicinal faces, regarding to (i) competition between step-flow and spiral growth on 6H-SiC, and (ii) role of off-angle and C/Si ratio for surface defect formation on 4H-SiC. For the competition between step-flow and spiral growth, a high C/Si ratio was found to enhance spiral growth, while a low C/Si ratio to enhance step-flow growth. For the surface defect formation on (0001)Si, a large off-angle and low C/Si ratio are preferrable to suppress major surface defects. In the case of (0001̄)C, thermal oxidation can be used to remove surface damages, thus suppressing major surface defects.

Surface Mechanisms in Homoepitaxial Growth on α-SiC{0001}-Vicinal Faces

One atomic layer of Si atoms 3 is grown on an Si-terminated SiC surface 1a having an Si polar face, and one atomic layer of C atoms 5 is further grown thereon. Then, Si and C are supplied to form an SiC layer. The surface of the SiC layer thus grown is a C polar face opposite to the Si polar face. That is, according to the above-described step, it is possible to grow an SiC polarity-reversed layer 1 x having a C polarity on an SiC layer 1 having an Si polarity, with one atomic layer of an Si intermediate layer b interposed therebetween. Consequently, it is possible to provide a technique to reverse the polarity of SiC on the surface.

Semiconductor device and semiconductor manufacturing method

Conductive filaments formed in Pt/NiO/Pt resistive switching (RS) cells were characterized by conductive atomic force microscopy (C-AFM) and cross-sectional transmission electron microscopy (XTEM) after the removal of top electrodes. The area and current of the filaments were directly detected by C-AFM. By examining various RS cells with different cell resistances in the low-resistance state (RLRS), it has been revealed that the RLRS variation in the range of 10–220 Ω is mainly caused by the variations in the area and shape of the filaments. XTEM was carried out on a filament that dominantly determines RLRS. The area of the filament significantly varied along the thickness direction of a NiO film, which was consistent with the speculation from C-AFM analysis. Furthermore, the filaments observed in this study consist of reduced NiO with an inclusion of platinum, the electrode material, owing to Joule heating by the current during forming.

https://iopscience.iop.org/article/10.7567/JJAP.52.041801/pdf

Tsunenobu Kimoto

Papers

Step-Controlled Epitaxial Growth of 4H-SiC and Doping of Ga as a Blue Luminescent Center

Avalanche phenomena in 4H-SiC p-n diodes fabricated by aluminum or boron implantation

Surface Mechanisms in Homoepitaxial Growth on α-SiC{0001}-Vicinal Faces

Semiconductor device and semiconductor manufacturing method

Microscopic Investigation of the Electrical and Structural Properties of Conductive Filaments Formed in Pt/NiO/Pt Resistive Switching Cells