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

Oxide deposition followed by high-temperature annealing in N2O has been investigated to improve the quality of 4H-SiC MOS structures. Annealing of deposited oxides in N2O at 1300oC significantly enhances the breakdown strength and decreases the interface state density to 3x1011 cm-2eV-1 at EC – 0.2 eV. As a result, high channel mobility of 34 cm2/Vs and 52 cm2/Vs has been attained for inversion-type MOSFETs fabricated on 4H-SiC(0001)Si and (000-1)C faces, respectively. The channel mobility shows a maximum when the increase of oxide thickness during N2O annealing is approximately 5 nm. A lateral RESURF MOSFET with gate oxides formed by the proposed process has blocked 1450 V and showed a low on-resistance of 75 mcm2, which is one of the best performances among lateral SiC MOSFETs reported.

Improved Dielectric and Interface Properties of 4H-SiC MOS Structures Processed by Oxide Deposition and N2O Annealing

4H-SiC MOSFETs on (03-38) Face

Epitaxial growth was performed on 8° off-axis 4H-SiC(0001) by horizontal hot-wall chemical vapor deposition (CVD) in a SiH4-C3H8-H2 system at 1550°C. High growth rates of 10–13 µm/h were attained by growth with a high SiH4 flow rate of 4.0 sccm. A mirror like surface was obtained by employing an optimum C/Si ratio and by an improved process of initial growth. The epilayers grown with an optimum C/Si ratio showed high purity in the low 1013 cm-3 range (n-type) and low trap concentrations in the low 1011 cm-3 range. Minority carrier lifetime was investigated by a differential microwave-detected photoconductance decay (µ-PCD) measurement. A long carrier lifetime of approximately 2 µs was obtained for a 50-µm-thick epilayer

Low-Concentration Deep Traps in 4H-SiC Grown with High Growth Rate by Chemical Vapor Deposition

An SiC power device possesses features like high breakdown voltage, fast switching capability, and high temperature operation, and is expected to be superior to conventional Si power devices. This paper clarifies the switching capability of an SiC Schottky barrier diode (SBD) in rectification of high frequency ac voltage. The dynamic behavior of the SiC SBD for switching operation is modeled based on semiconductor physics and device structure, and is characterized by its dc current-voltage (I-V) and ac capacitance-voltage (C-V) characteristics. A C-V characterization system, which measures capacitance using a dc bias voltage corresponding to the maximum rated voltage of the SiC SBD, is developed. The C-V characteristics are evaluated through experiments over the rated voltage range. These results explain the punch-through structure and device parameters. The dynamic behavior of the proposed model is validated through experiments on half-wave rectification of ac voltages over a wide frequency range. As a relational expression of voltage, current, and frequency of an applied ac sinusoidal voltage, the performance criterion of the device is established for rectification. The model also quantitatively assesses the switching capability of SiC SBDs. The model and performance criteria are beneficial for circuit design and device evaluation.

/pdf/evaluation-of-high-frequency-switching-capability-of-sic-ycia0veoss.pdf

Evaluation of High Frequency Switching Capability of SiC Schottky Barrier Diode, Based on Junction Capacitance Model

We investigated the carrier lifetime and Z1/2 center density of thick n-type 4H-SiC epilayers, which were oxidized and subsequently annealed in Ar at high temperatures. The Z1/2 center density decreased below the detection limit in the region to, at least, a 130 µm depth by thermal oxidation. After subsequent high-temperature annealing, the Z1/2 center density increased with increasing annealing temperature, while the distribution of the Z1/2 center density was nearly uniform to a 130 µm depth. The carrier lifetime could be controlled from 26 to 2.4 µs by changing the annealing temperature from 1600 to 1800 °C.

https://iopscience.iop.org/article/10.7567/APEX.9.061303/pdf

Tsunenobu Kimoto

Papers

Improved Dielectric and Interface Properties of 4H-SiC MOS Structures Processed by Oxide Deposition and N2O Annealing

4H-SiC MOSFETs on (03-38) Face

Low-Concentration Deep Traps in 4H-SiC Grown with High Growth Rate by Chemical Vapor Deposition

Evaluation of High Frequency Switching Capability of SiC Schottky Barrier Diode, Based on Junction Capacitance Model

Control of carrier lifetime of thick n-type 4H-SiC epilayers by high-temperature Ar annealing