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

We formed a low-resistance p region by high-dose aluminum (Al) ion implantation in the 4H-SiC (0001) face, and fabricated and characterized planar pn diodes by Al or boron (B) ion implantation. In Al ion implantation, the minimum sheet resistance of 3.6 kω/□ (p-type) is obtained by high-temperature implantation and high-temperature annealing. Excellent rectification was verified in planar pn diodes, in which the surface p+ layer was formed by high-temperature implantation of Al ions and the p layer was formed by room-temperature implantation of high-energy B ions. We achieved a high blocking voltage of 2900 V (90% of the theoretical withstand voltage), a low on-resistance of 8.0 mωcm2, and avalanche breakdown characteristics of a positive temperature coefficient for the blocking voltage. We fabricated a 4H-SiC (1120) pn diode, which has not been disclosed previously, and obtained a high blocking voltage of 1850 V (70% of the theoretical blocking voltage). © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(12): 44–51, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10162

High‐voltage 4H‐SiC pn diodes fabricated by p‐type ion implantation

Homoepitaxial chemical vapor deposition of 6H-SiC at low temperatures on {014} substrates has been investigated. The crystal growth was carried out using a SiH4-C3H8-H2 system in the temperature range of 1000~1500°C. Crystallinity of grown layers was characterized by means of reflection high-energy electron diffraction and etch-pit observation. The influences of surface polarity and growth conditions on crystallinity of grown layers were investigated. Significant effects of C/Si ratio on the growth were observed. Homoepitaxial growth of 6H-SiC was realized on (01)C-face substrates at temperatures as low as 1100°C, which is 700°C lower than that on {0001} basal planes.

http://iopscience.iop.org/article/10.1143/JJAP.31.3655/pdf

Homoepitaxial Chemical Vapor Deposition of 6H–SiC at Low Temperatures on {01\bar14} Substrates

SiC crystallizes in a variety of polytypes, each with unique electrical, optical, thermal, and mechanical properties. The physical properties of SiC are important subjects of academic study, as well as critical parameters for accurate simulation and design of devices. In this chapter we review the important physical properties of SiC.

Physical Properties of Silicon Carbide

GaN/SiC heterojunction bipolar transistors (HBTs) with an ultrathin AlN spacer layer at the n-GaN/p-SiC emitter junction are proposed for the control of the electronic properties of GaN/SiC heterojunctions. The insertion of an AlN spacer is found to be promising in terms of improving electron injection efficiency owing to the reduced potential barrier (0.54 eV) to electron injection and reduced recombination via interface traps. We also investigated the effect of pre-irradiation of active nitrogen atoms (N*) prior to AlN growth for the control of the electronic properties of GaN/AlN/SiC heterojunctions. We found that the potential barrier was further reduced to 0.46 eV by N* pre-irradiation. The HBT structure was successfully fabricated using our newly developed process featuring ion implantation and Pd ohmic contacts to obtain a low contact resistivity to a p-SiC base at a temperature as low as 600 °C. A fabricated HBT without an AlN layer showed a low current gain (α ~ 0.001), whereas the GaN/AlN/SiC HBT showed improved current gains of 0.1 in the case of using a 1-nm-thick AlN spacer without N* pre-irradiation and 0.2 in the case of using a 2-nm-thick AlN spacer with N* pre-irradiation.

https://iopscience.iop.org/article/10.7567/JJAP.53.034101/pdf

Effect of ultrathin AlN spacer on electronic properties of GaN/SiC heterojunction bipolar transistors

We propose an analysis method for the accurate estimation of the hole trap (H1, E V + 0.85 eV) concentration in n-type GaN via minority carrier transient spectroscopy (MCTS). The proposed method considers both the hole occupation during a filling (current injection) period and the quick carrier recombination via the hole traps near the depletion layer edge immediately after a reverse bias is applied. The reverse bias voltage dependence of the MCTS spectrum indicates that an accurate trap concentration, as well as the hole diffusion length and electron capture cross section of the hole trap, can be determined.

https://iopscience.iop.org/article/10.7567/APEX.11.071002/pdf

Tsunenobu Kimoto

Papers

High‐voltage 4H‐SiC pn diodes fabricated by p‐type ion implantation

Homoepitaxial Chemical Vapor Deposition of 6H–SiC at Low Temperatures on {01\bar14} Substrates

Physical Properties of Silicon Carbide

Effect of ultrathin AlN spacer on electronic properties of GaN/SiC heterojunction bipolar transistors

Accurate method for estimating hole trap concentration in n-type GaN via minority carrier transient spectroscopy