bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Surface Etching Conditions on Stacking Faults in 4H-SiC Epitaxy
Authors: Rana Tawhid , Chung Gil Yong , Anderson Steve , Manning Ian , Bowen Willie , Sanchez Edward
Published: July 2019

Epilayers grown on substrates etched by various etching conditions were studied for stacking fault defects. Substrates were etched by H2, H2+ HCl and H2 + CxHy gases prior to epilayer growth for comparison. High density of SF was observed in the epilayers when H2+HCl or H2+CxHy gas mixtures were used. On the other hand, much lower density of stacking faults (SF) (<1 cm-2) was observed in the epilayer grown on the surface etched by only H2 gas. However, a high number of pits were generated in the epilayer grown on substrate etched by H2 only, which can be considered to be tradeoff of achieving low SF in epilayer by substrate etching. We also conclude from our experimental results that C rich surface is more favorable to generate SF in epilayer compared to Si rich surface.
New SiC Epitaxial Growth Process with up to 100% BPD to TED Defect Conversion on 150mm Hot-Wall CVD Reactor
Authors: Höchbauer Tobias , Heidorn Christian , Tsavdaris Nikolaos
Published: July 2019

The future challenges for SiC device technology are cost reduction and increased reliability. A key point to achieve that is the increase of yield during epitaxial layer growth through the reduction of structural defects (such as basal plane dislocations and triangle defects), an increased thickness and doping uniformity, and a high growth rate. Despite significant advancements in SiC epitaxial growth technology, it still constitutes a big challenge to find the optimum working point at which all those requirements are fulfilled. By implementing a new epitaxial layer growth process, we are able to grow basal plane dislocation free epitaxial layers, while the density of other structural defects remains low. Additionally, intra-wafer thickness and doping uniformities of the epitaxial layers are further improved.
Germanium Incorporation in Silicon Carbide Epitaxial Layers Using Molecular Beam Epitaxy on 4H-SiC Substrates
Authors: Pezoldt Joerg , Zgheib Charbel , Stauden Thomas , Ecke Gernot , Kups Thomas , Jacobs Heiko O. , Weih Petia
Published: July 2019

Ternary (Si1-xCy)Gex+y solid solutions were grown on Si-face 4H-SiC applying atomic layer molecular beam epitaxy at low temperatures. The grown layers consist of twinned 3C-SiC revealed by cross section electron microscopy. The germanium was incorporated on silicon lattice sites as revealed by atomic location by channeling enhanced microanalysis transmission electron microscopy studies. The Ge concentration of the grown 3C-(Si1-xCy)Gex+y heteroepitaxial layers decreases with increasing growth temperatures, but exceeds the solid solubility limit.
Effect of HCL on Surface Free Energy of SiC during CVD Trench Filling
Authors: Mochizuki Kazuhiro , Ji Shi Yang , Kosugi Ryoji , Yonezawa Yoshiyuki , Okumura Hajime
Published: July 2019

Trench-filling epitaxial growth of 4H-SiC by chemical vapor deposition (CVD) with and without HCl was analyzed based on a continuum-diffusion model including the Gibbs–Thomson effect. Qualitative reproduction of the reported observation showed that the effective surface free energy of SiC during CVD can be doubled by the addition of HCl
Novel Carbon Treatment to Create an Oriented 3C-SiC Seed on Silicon
Authors: Zielinski Marcin , Monnoye Sylvain , Mank Hugues , Torregrosa Frank , Grosset Gregory , Spiegel Yohann
Published: July 2019

In this contribution we investigate the possibility to obtain an oriented 3C-SiC seed on Si substrate “pre-carbonized” through Plasma Immersion Ion Implantation (PIII) process by combining PIII with high temperature annealing.
Evaluation of the Impact of Al Atoms on SiO2/ SiC Interface Property by Using 4H-SiC n+-Channel Junctionless MOSFET
Authors: Takeda Hironori , Hosoi Takuji , Shimura Takayoshi , Watanabe Heiji
Published: July 2019

To investigate the impact of Al atoms on channel mobility at SiO2/SiC interface, we fabricated the junctionless metal-oxide-semiconductor field-effect transistors (MOSFETs), in which thin n+-SiC epitaxial layers with and without Al+ ion implantation were used as a channel, and compared their electrical characteristics. The effective mobility (meff) of n+-channel junctionless MOSFET without Al doping was estimated to be 14.9 cm2/Vs, which is higher than inversion-mode MOSFET fabricated with the same gate oxidation condition (3.1 cm2/Vs). The meff values of the MOSFETs with low Al doping concentration (5´1017 and 1´1018 cm-3) were almost the same as that of Al-free MOSFET, and the device with the highest Al doping (5´1018 cm-3) exhibited slight mobility degradation of about 15% compared to the other devices. Hall mobility in thick n+ layer with the highest Al doping was also slightly degraded, suggesting that Al atoms in the channel are not the major cause of degraded SiO2/SiC interface property.
Cryogenic Characterization of NH3 Post Oxidation Annealed 4H-SiC Trench MOSFETs
Authors: Berens Judith , Pobegen Gregor , Aichinger Thomas , Rescher Gerald , Grasser Tibor
Published: July 2019

We employed the thermal dielectric relaxation current method (TDRC) for the cryogenic characterization of ammonia (NH3) post oxidation annealed 4H silicon carbide (4H-SiC) trench MOSFETs. We studied differences and similarities between annealing in nitric oxide (NO) and NH3. In NO and NH3 annealed trench MOSFETs, the same type of traps was found near the conduction band edge of 4H-SiC. The TDRC-signal consists of two peaks caused by interface states with a thermal emission barrier of 0.13 eV and near interface traps (NITs) with an emission barrier of approximately 0.3 eV. Significantly more interface traps close to the conduction band edge were found for the NH3 annealed devices compared to the NO annealed ones. Our TDRC results indicate that NH3 post oxidation anneal (POA) affects trap levels in a different way than NO POA.
Modified Hot-Zone Design for Large Diameter 4H-SiC Single Crystal Growth
Authors: Choi Jung Woo , Kim Jung Gyu , Jang Byung Kyu , Ko Sang Ki , Kyun Myung Ok , Seo Jung Doo , Ku Kap Ryeol , Choi Jeong Min , Lee Won Jae
Published: July 2019

6-inch 4H-SiC single crystal was grown with modified hot-zone design for large diameter crystal. The simulation data confirmed reduced temperature gradient between center and edge region of growing front, and actual growth experiment exhibited that SiC crystal with good quality was obtained with modified hot-zone design without any quality degradation in edge region of bulk crystal. Based on the mapping measurement of FWHM (Full width at half maximum) value in X-ray rocking curve, the crystal quality of SiC crystals from middle and top region of grown ingot was observed to be almost identical. Furthermore, various properties of SiC crystal grown with modified hot-zone design have been systematically investigated.
Accurate Dopant and Interface Characterization in Oxidized SiC with Refined Non-Contact C-V Technique
Authors: Savtchouk Alexandre , Wilson Marshall , Almeida Carlos , Marinskiy Dmitriy , Hillard Robert , Lagowski Jacek
Published: July 2019

The non-contact C-V technique has been recently gaining interest as a precise, cost and time effective metrology for wide-bandgap semiconductors. Originally focused on dopant measurement, non-contact C-V has been expanding to encompass wide-bandgap surface and interface characterization, including complex reliability issues critical for the future of power devices. In this work, we report progress achieved using a new direct method for determining the flatband voltage, VFB, and capacitance, CFB. Experimental results are presented for n-type oxidized epitaxial 4-H SiC. They demonstrate the approach and the unique self-consistent measurement producing an entire set of pertinent electrical parameters, including the interface trap density, Dit.
Evidence for an Abrupt Transition between SiO2 and SiC from EELS and Ab Initio Modelling
Authors: Cottom Jonathon , Mistry Manesh V. , Gruber Gernot , Pobegen Gregor , Aichinger Thomas , Shluger Alexander L.
Published: July 2019

Electron energy loss spectroscopy (EELS) and ab initio simulations are combined in this study to produce an atomistic interpretation of the interface morphology in lateral 4H-SiC / SiO2 MOSFETs with deposited gate oxides. This allows the question of interface abruptness, and the presence the postulated SiOxCy interlayer to be explored for a subset of devices with deposited oxides. From comparison between EELS and ab initio calculation the interfaces considered are best described as abrupt, but stepped, transitioning without any of the carbon excess or SiOxCy interlayer that have been described for other devices observed.
DFT Calculation for Oxidation Reaction of SiC(0001)
Authors: Ono Tomoya
Published: July 2019

The reaction-limiting process for the oxidation of SiC(0001) was investigated by density functional theory calculation. I found that the oxygen molecule insertion to the interfacial SiC bonds is the limiting process and the barrier is 3.21 eV. It is also found that the CO detachment is not limiting process because the barrier becomes small when the interfacial C atom is surrounded by three O atoms.
Atomic Coordination Analysis of Nitrogen Introduced in SiO2/ SiC Interface and SiO2 Layer by XAFS Measurement
Authors: Kunisu Masahiro , Ogawa Shingo , Sameshima Junichiro , Yoshikawa Masanobu
Published: July 2019

Although the nitridation by N2O or NO oxidation with annealing has been used in order to reduce interface trap density, the atomic location or coordination environment of nitrogen atom have been still unclear. In this study, we have investigated atomic coordination environment of nitrogen atom in both SiO2/SiC interface and SiO2 layer after nitridation by N2O annealing using XAFS measurements and ab initio multiple scattering calculations. Nitrogen in SiO2 layer was suggested to have the same atomic coordination environments as general SiON thin film. On the other hand, in SiO2/SiC region, nitrogen atoms were isolated and occupied the C-site of SiC structure, and it was confirmed that nitrogen atoms were surrounded by silicon atoms and strong Si-N bonds were formed in the interface region that was not eliminated by HF etching.
Analysis of Basal Plane Dislocation Dynamics in 4H-SiC Crystals during High Temperature Treatment
Authors: Raghothamachar Balaji , Yang Yu , Guo Jian Qiu , Dudley Michael
Published: July 2019

Direct observation of thermal gradient induced motion of basal plane dislocations by in-situ synchrotron X-ray topography imaging of PVT-grown 4H-SiC wafers subject to high temperature treatment has provided an opportunity to analyze the movement of dislocations. Dislocations with Burgers vector along the off-cut [11-20] direction were found to be the only dislocations involved in deformation during heat treatment and the segments of dislocations used for velocity measurements were found to be either pure screw comprised of both Si-and C-core partials or 60° dislocations comprised of purely Si cores. Using the kink-diffusion model, the activation energies for dislocation motion have been calculated from the velocity data for each of these dislocation types and found to be 3.28eV for pure screw and 2.21eV for 60° dislocation segments, respectively.
Initiation of Shockley Stacking Fault Expansion in 4H-SiC P-i-N Diodes
Authors: Okada Aoi , Ota Chiharu , Nishio Johji , Goryu Akihiro , Iijima Ryosuke , Nakayama Koji , Kato Tomohisa , Yonezawa Yoshiyuki , Okumura Hajime
Published: July 2019

To understand the effects of temperature and injection current density on expansion of Shockley stacking faults (SSFs) from basal-plane dislocations in 4H-SiC p-i-n diodes, the threshold current density for SSF expansion was investigated at eight temperatures by electroluminescence image observation. The threshold injection current density was found to decrease at lower temperatures and to increase at higher temperatures. We identified the origin of this temperature dependence and found that the limiting factor for expansion differed depending on the temperature.
Combined EPR and Photoluminescence Study of Electron and Proton Irradiated 3C-SiC
Authors: Al Atem Abdul , Bratus Victor , Canut Bruno , Lefevre Jeremie , Guillot Gérard , Bluet Jean Marie
Published: July 2019

Combined Photoluminescence (PL) and electron paramagnetic resonance (EPR) spectroscopy have been used to characterize cubic silicon carbide (3C-SiC) samples after electron and proton irradiation. We have studied the effects of the thermal annealing (500-1000°C) on the PL intensity in the visible and the near infra-red (NIR) ranges and identified the point defects formation after these two processes of irradiation.
Newly Resolved Phonon-Assisted Transitions and Fine Structure in the Low Temperature Wavelength Modulated Absorption and Photoluminescence Spectra of 6H SiC
Authors: Klahold Walter M. , Choyke Wolfgang J. , Devaty Robert P.
Published: July 2019

We measured the low temperature wavelength modulated absorption and low temperature photoluminescence spectra of relatively high purity (n~1014-1015 cm-3) 6H SiC boule and epi layers at high wavelength resolution (0.1-0.7 Å) to adequately separate and identify phonon-assisted absorption and recombination processes due to free excitons. As a result we have identified newly resolved or weak features in both spectra which we associate with previously unidentified momentum conserving (MC) phonons. We obtain the energies of 21 of the 36 possible MC phonons in 6H SiC and a more accurate estimate of the exciton bandgap, Egx = 3.0225±0.0003 eV. In several of the phonon-assisted absorption onsets we also observe fine structure and variations in the measured spin-orbit splitting, which relate to a fourfold splitting of the free exciton energy bands.
Thermal Annealing of High Dose P Implantation in 4H-SiC
Authors: Calabretta Cristiano , Zimbone Massimo , Barbagiovanni Eric G. , Boninelli Simona , Piluso Nicolo , Severino Andrea , di Stefano Maria Ausilia , Lorenti Simona , Calcagno Lucia , La Via Francesco
Published: July 2019

In this work, we have studied the crystal defectiveness and doping activation subsequent to ion implantation and post-annealing by using various techniques including photoluminescence (PL), Raman spectroscopy and transmission electron microscopy (TEM). The aim of this work was to test the effectiveness of double step annealing to reduce the density of point defects generated during the annealing of a P implanted 4H-SiC epitaxial layer. The outcome of this work evidences that neither the first 1 hour isochronal annealing at 1650 - 1700 - 1750 °C, nor the second one at 1500 °C for times between 4 hour and 14 hour were able to recover a satisfactory crystallinity of the sample and achieve dopant activations exceeding 1%.
On the Origin of Charge Compensation in Aluminum-Implanted n-Type 4H-SiC by Analysis of Hall Effect Measurements
Authors: Weisse Julietta , Hauck Martin , Sledziewski Tomasz , Krieger Michael , Bauer Anton J. , Mitlehner Heinz , Frey Lothar , Erlbacher Tobias
Published: July 2019

Aluminum implanted 4H-SiC often shows an unexpected increase of the free hole density at elevated temperatures in Hall Effect measurements. Here we show that this phenomenon cannot solely be traced down to the Hall scattering factor and the presence of excited acceptor states. It is necessary to assume an additional defect center in the lower half of the band gap with ionization energies higher than that of aluminum to explain this behavior. Therefore, we investigated ion-implanted square van-der-Pauw samples with Hall Effect and complementary SIMS measurements. An analysis of the data using the neutrality equation reveals compensation ratios of 20 % to 90 %, depending on the aluminum concentration and the concentration of the deep defect center of up to 50 % of the doping.
Decoration of Al Implantation Profiles in 4H-SiC by Bevel Grinding and Dry Oxidation
Authors: Kocher Matthias , Erlbacher Tobias , Rommel Mathias , Bauer Anton J.
Published: July 2019

The possibility to analyze micrometer scaled 2D implantation profiles is essential for improving SiC power devices. Due to the fact that the oxidation rate depends on the doping concentration a rather simple method was developed in order to decorate highly doped (aluminum) implantation profiles. For this purpose, different samples were grinded with a shallow bevel angle and subsequently oxidized. It could be shown that this method allows analyzing the implantation depth of different box-shape implanted samples. Furthermore the ability to distinguish micrometer scaled 2D profiles for a state-of-the-art SiC power device could be shown.
Improved Field Effect Mobility in Si-Face 4H-SiC MOSFETs with a Deposited SiNx Interface Layer
Authors: Kumazawa Teruaki , Okamoto Mitsuo , Iijima Miwako , Iwahashi Yohei , Fujikake Shinji , Araoka Tuyoshi , Tawara Tae , Kimura Hiroshi , Hamada Kimimori , Harada Shinsuke , Okumura Hajime
Published: July 2019

The SiO2/SiC interface quality has a significant effect on the performance of 4H-SiC MOS devices. The introduction of nitrogen to the SiO2/SiC interface is a well-known method for reducing the interface state density (Dit). In this study, we introduced nitrogen to the SiO2/SiC interface by forming SiNx films using atomic layer deposition (ALD) and thus improved the interface quality. O2 annealing with a SiNx interface layer of optimal thickness enhanced the field effect mobility.
Comparison between Ni-SALICIDE and Self-Aligned Lift-Off Used in Fabrication of Ohmic Contacts for SiC Power MOSFET
Authors: Sledziewski Tomasz , Erlbacher Tobias , Bauer Anton J. , Frey Lothar , Chen Xi Ming , Zhao Yan Li , Li Chengzhan , Dai Xiao Ping
Published: July 2019

A comparison between self-aligned process (using lift-off) and Ni-SALICIDE used in fabrication of ohmic contacts for SiC Power MOSFET is done. Both processes are demonstrated for 3.3 kV SiC VDMOS transistors fabricated on 100 mm substrates. It is shown that the Ni-SALICIDE process with first silicidation at 500 °C does not degrade the electrical properties of silicon dioxide; particularly, a degradation of the interlayer dielectric between source and gate is not evident. Additionally, this first silicidation is found to have a positive impact on the specific resistance of contacts formed on p-type SiC using NiAl2.6% as an ohmic metal.
Surge Current and Avalanche Robustness of Commercial 1200 V SiC Schottky Diodes
Authors: Sundaresan Siddarth G. , Mulpuri Vamsi , Singh Ranbir
Published: July 2019

This paper investigates the 10 ms surge current (IFSM) and single-pulse avalanche energy (EAS) limits of 1200 V/10 A SiC Schottky rectifiers from several commercial vendors. GeneSiC’s 1200 V/10 A diode recorded maximum IFSM values of 162 A at TC=25°C and 135 A at TC=150°C, which were the highest amongst investigated devices. The diode sustains junction temperatures as high as 910°C during surge current operation, which results in eventual failure of the Aluminum based metallization.
Influence of Trench Design on the Electrical Properties of 650V 4H-SiC JBS Diodes
Authors: Rusch Oleg , Moult Jonathan , Erlbacher Tobias
Published: July 2019

This work presents a design study of customized p+ arrays having influence on the electrical properties of manufactured 4H-SiC Junction Barrier Schottky (JBS) diodes with designated electrical characteristics of 5 A forward and 650 V blocking capabilities. The effect of the Schottky area consuming p+ grid on the forward voltage drop, the leakage current and therefore the breakdown voltage was investigated. A recessed p+ implantation, realized through trench etching before implanting the bottom of the trenches, results in a more effective shielding of the electrical field at the Schottky interface and therefore reduces the leakage current. Customizing the p+ grid array in combination with the trench structure, various JBS diode variants with active areas of 1.69 mm2 were fabricated whereas forward voltage drops of 1.58 V @ 5 A with blocking capabilities up to 1 kV were achieved.
Research on the Key Problems in the Industrialization of SiC Substrate Materials
Authors: Gao Pao , Xin Jun , Yan Cheng Feng , Kong Hai Kuan , Chen Jian Jun , Liu Xue Chao , Shi Er Wei
Published: July 2019

The development of semiconductor materials and devices will lead to a new industrial technology revolution, in which the Silicon Carbide (SiC) substrate material has very excellent performance and it is especially suitable for manufacturing wave length lasers, white light emitting tubes, high-frequency, high-temperature and high-power devices, etc. This paper focuses on solving the key problems for producing large size and low defects of SiC crystals by the PVT method, such as the preparation and purification of the high purity raw material, the simulation of the temperature field, the control of the crystal defects and the growth of the large size SiC crystals.It is critical for the development of SiC industry.
Mechanisms and Characteristics of Large-Area High-Current-Density 4H-SiC Trench Junction Barrier Schottky Diodes
Authors: Tang Yi Dan , Dong Sheng Xu , Bai Yun , Yang Cheng Yue , Li Chengzhan , Liu Xin Yu
Published: July 2019

Mechanisms and characteristics of optimized main junction for 4H-SiC trench junction barrier Schottky (TMJBS) diodes were investigated by theories and experiments. From these simulation and experimental values, we can conclude that TMJBS device has better reverse performance, such as the best reverse blocking capability and lowest reverse surface leakage current than the conventional JBS and TJBS device while maintaining good forward characteristics. Furthermore, The large area TMJBS Diodes with high current density show the better reverse characteristics than the small area one at an acceptable forward characteristics. The TMJBS structure can significantly reduce the influence of the Schottky interface and is more suitable for manufacturing high current density and large area devices.
Influence of Dopant Concentration on Dislocation Distributions in 150mm 4H SiC Wafers
Authors: Manning Ian , Chung Gil Yong , Sanchez Edward , Dudley Michael , Ailihumaer Tuerxun , Guo Jian Qiu , Goue Ouloide , Raghothamachar Balaji
Published: July 2019

Shifts in the spatial distribution of threading dislocations in 150 mm 4H SiC wafers were examined as a response to intentional changes in both the flow of the nitrogen source gas used to control resistivity during bulk crystal growth, and the growth rate. The density of threading edge and screw dislocations was found to be more evenly distributed in wafers produced under a high-growth rate, low-resistivity process. This result corresponded to a flattening of the resistivity distribution, and a ~34% reduction in on-and off-facet resistivity differential. The effect was attributed to regularized 4H island coalescence due to modulation of step terrace width.
Suppression of Short-Channel Effects in 4H-SiC Trench MOSFETs
Authors: Ishii Tomoyasu , Kuroki Shin Ichiro , Sezaki Hiroshi , Ishikawa Seiji , Maeda Tomonori , Makino Takahiro , Ohshima Takeshi , Östling Mikael , Zetterling Carl Mikael
Published: July 2019

Submicron 4H-SiC MOSFETs are attractive for high frequency operation of 4H-SiC integrated circuits. However, the short channel effects, such as threshold voltage lowering, would be induced at the short-channel devices. In this work, short channel effects were investigated with planar and trench 4H-SiC MOSFETs, and the suppression of the short channel effect with the trench structure was achieved.
An Investigation into the Dynamic Behavior of 3.3kV MOSFETs Body Diode
Authors: Mihaila Andrei , Bianda Enea , Knoll Lars , Godignon Philippe , Soler Victor , Kranz Lukas , Alfieri Giovanni , Badstübner Uwe , Canales Francisco , Rahimo Munaf
Published: July 2019

This paper presents a dynamic investigation of the body diode behavior of MOSFETs rated for 3.3kV applications. The body diodes of MOSFETs with different cell designs and pitch sizes have been used. The turn-off behavior of the body diode is compared to that of a 3.3kV JBS diode.
Effect of Temperature on the Electrical Characteristics of 4H-SiC Planar n/p-Type Junctionless FET: Physics Based Simulation
Authors: Vudumula Pavan , Kotamraju Siva
Published: July 2019

In this paper, we have explored planar junctionless FET (JLFET) in 4H-SiC as a potential device for future industrial applications. We show the differences in static electrical characteristics (Id-Vg, Id-Vd, subthreshold current and Ion/Ioff ratio) between n and p-type JLFETs whilst varying the lattice temperature (T) from 300 K to 700 K using 2D numerical simulations. The oxide-SiC interface traps have shown minimum influence on the device current conduction characteristics. For the same one-micron channel length and an equal area of cross-section, the p-type JLFET exhibits lower off-state current (Ioff) leading to higher Ion/Ioff ratio, a higher threshold voltage (VTH) and lower subthreshold current in comparison to the n-type JLFET.
Dependence of the Carrier Removal Rate in 4H-SiC PN Structures on the Irradiation Temperature
Authors: Lebedev Alexander A. , Davydovskaya Klavdia S. , Kozlovski Vitalii V. , Korolkov Oleg , Sleptsuk Natalja , Toompuu Jana
Published: July 2019

The influence of 15 MeV proton irradiation temperatures (room temperature (RT) - 700 ° C) on the processes of defect formation in commercially available 4H-SiC JBS structures has been studied. It has been shown that the carrier removal rate does not depend on the irradiation temperature. At the same time, the irradiation temperature affected on the spectrum of introduced radiation defects. The conclusion about the possible influence of SiC crystal lattice structural defects on the processes of radiation defect formation has been made.
Influence of High-Temperature Bias Stress on Room-Temperature VT Drift Measurements in SiC Power MOSFETs
Authors: Habersat Daniel B. , Lelis Aivars J. , Green Ronald
Published: July 2019

Our results reinforce the notion of the need for an improved high-temperature gate bias (HTGB) test method — one which discourages the use of slow (greater than ~1 ms) threshold-voltage (VT) measurements at elevated temperatures and includes biased cool-down if room temperature measurements are performed, to ensure that any ephemeral effects during the high-temperature stress are observed. The paper presents a series of results on both state-of-the-art commercially-available devices as well as older vintage devices that exhibit enhanced charge-trapping effects. Although modern devices appear to be robust, it is important to ensure that any new devices released commercially, especially by new vendors, are properly evaluated for VT stability.
Design Considerations for Robust Manufacturing and High Yield of 1.2 kV 4H-SiC VDMOS Transistors
Authors: Schlichting Holger , Sledziewski Tomasz , Bauer Anton J. , Erlbacher Tobias
Published: July 2019

Production yield is a major factor for semiconductor device manufacturing. To produce high performance devices cost efficiently, it is important to know the process windows of the implemented production technology. This can influence the yield in different ways. One of the critical steps is the photolithography. In this work the impact of misalignment within the technological limits is analyzed and discussed. 4H-SiC VDMOS Transistors were produced and the electrical characteristics were compared with the overlay accuracy of the devices. Small change in channel length can lead to large impact on the electrical characteristic. Especially when the channel length reaches values near to the critical length for short channel effects (SCEs), small overlay inaccuracies influence the electrical characteristic of the devices in an increasing manner. Different cell designs were analyzed regarding their robustness to misalignment.
Evaluation of Basal Plane Dislocation Behavior in the Epitaxial Layer on a 4H-SiС Wafer Fabricated by the Solution Growth Method
Authors: Seki Kazuaki , Kusunoki Kazuhiko , Harada Shinsuke , Ujihara Toru
Published: July 2019

A 4H-SiC 4° off-wafer fabricated from a bulk crystal grown using the solution method has high quality with extremely low-density threading screw (TSD) and basal plane (BPD) dislocations. For application to electronic devices, we formed an epitaxial layer on the solution-method-prepared wafer via chemical vapor deposition and evaluated the BPD in the epitaxial layer using synchrotron X-ray topography and molten KOH etching. The BPD density of the epitaxial layer formed on the solution-grown crystals was extremely low. Bulk crystals fabricated as wafers by the solution method are expected to be applied to high-voltage bipolar devices that do not suffer from degradation of forward characteristics.
A Monolithic 500°C D-Flip Flop Realized in Bipolar 4H-SiC TTL Technology
Authors: Shakir Muhammad , Hou Shuo Ben , Zetterling Carl Mikael
Published: July 2019

This work presents the design, in-house fabrication, and electrical characterization of a monolithic medium scale integrated (MSI) D-type flip-flop (DFF). It consists of 65 n-p-n bipolar transistors and 49 integrated resistors. The monolithic bipolar DFF is realized using basic gates by employing the structured way of implementation, whereas the basic gates are implemented by employing the conventional transistor-transistor logic (TTL). The positive-edge-triggered DFF, with synchronous active-low reset is characterized in the temperature range of 25-500 °C. The circuit has been tested in two modes of operation; data input mode and clock divider. Non-monotonous temperature dependence is observed for the flip-flop propagation-delay clock-to-output (tPCQ), rise-time and fall-time; decreases with the temperature in the range 25 °C to 300 °C, while it increases in the range 300 °C to 500 °C. The transient response has also been measured at a clock frequency of 100 kHz. At T = 400 °C and VCC = 15 V, the DFF consumes minimum energy ≈ 234 nJ.
A Study on Fastening the Switching Speed for Wide Bandgap Semiconductor Based Super Cascode
Authors: Wang Xiang Guo , Yamamoto Masayuki
Published: July 2019

The Super Cascode is a series connected structure with a normally-off low voltage Si-MOSFET and multiple normally-on wide bandgap semiconductors. It has low switching losses compared with silicon based bipolar devices, and low on-resistance and low cost compared with other single high voltage normally-off wide bandgap semiconductor devices. In practice, however, there are inevitable parasitic inductances, which result in the increase of switching losses. The method is proposed to eliminate the common-source inductances (CSIs), such as using stack-die configuration with each device and adding an additional inductance in the gate loop of Si-MOSFET. It is numerically shown that the rise and fall times of the proposed method were 33.5% and 7.2% faster than the conventional one, respectively.
Improving 5V Digital 4H-SiC CMOS ICs for Operating at 400°C Using PMOS Channel Implantation
Authors: Albrecht Matthaeus , Erlbacher Tobias , Bauer Anton J. , Frey Lothar
Published: July 2019

In this work, the impact of a shallow aluminum channel implantation on the channel properties of SiC p-MOSFETs and digital SiC CMOS devices is investigated. For this purpose, p-MOSFETs, CMOS inverters and ring oscillators with different channel implantation doses were fabricated and electrically characterized. The threshold voltage of the resulting p-MOSFETs was shifted from-5 V to-3.6 V whereas the effective channel mobility was slightly decreased from 11.8 cm2/Vs to 10.2 cm2/Vs for a p-MOSFET channel implantation dose of 2∙1013 cm-2 compared to the non-implanted channel. The resulting p-MOSFETs enable SiC CMOS logic circuits to operate with a 5 V power supply and to satisfy 5 V TTL input level specification over the whole temperature range of 25°C to 400°C. Furthermore the propagation delay time of inverters was reduced by 80% at 25°C and 40% at 400°C compared to inverters without p-MOSFET channel implantation.
Improved Offset Voltage Stability of 4H-SiC CMOS Operational Amplifier by Increasing Gamma Irradiation Resistance
Authors: Masunaga Masahiro , Sato Shintaroh , Kuwana Ryoh , Hara Isao , Shima Akio
Published: July 2019

We modified the active layout of an operational amplifier (op-amp) to exhibit high gamma irradiation resistance of over 100-kGy using our 4H-SiC complementary MOS technology, which can be applied for measuring instruments installed in nuclear power plants. The op-amp with the modified active layout features both a thin gate oxide and newly developed gate-electrode structure for suppressing the leakage current. From an experiment we conducted, the leakage current of the p-channel MOSFET with modified active layout remained unchanged from the initial value after irradiation, although that of it with the conventional layout we previously evaluated increased by about two orders of magnitude. The offset voltage of the improved op-amp was maintained below 2.8 mV up to 100-kGy irradiation. The improved op-amp also showed a healthy amplification characteristic without distortion.
Power Loss Comparison in a BOOST PFC Circuit Considering the Reverse Recovery of the Forward Diode
Authors: Shao Wei Hua , Li Xiao Ling , Jiang Hua Ping , Guo Xuan , Zeng Zheng , Ran Li , Mawby Philip  Andrew
Published: July 2019

The nature of diode reverse recovery is analyzed in this paper, and the reverse recovery loss is evaluated in a BOOST PFC converter using a silicon (Si) or silicon carbide (SiC) diode in the forward branch. Mathematical models of the forward conduction and reverse recovery losses are established to assess the influence of Si and SiC diodes. To characterize and quantify the losses related to diode reverse recovery, an 85~265V AC to 400V DC, 2kW BOOST PFC prototype is built with switching frequencies of 65kHz. It is found that the reverse-recovery inherent in a Si diode cannot be neglected. The switching loss is substantially smaller when the diode is a SiC one. In order to investigate further, a double pulse test rig is established, with the switch and the diode being either Si or SiC. The experimental results demonstrate that with a SiC diode, not only the diode conduction losses but also the transistor turn-on loss is greatly reduced.
Social Media Marketing and Customer Engagement: A Review on Concepts and Empirical Contributions
Authors: Dissanayake D. M. R. , Siriwardana A. , Ismail N.
Published: July 2019

The present context of digitalized business era reshapes marketing promotional strategies whilst social media plays a pivotal role within. Empirical investigations found clarifying how modern marketing communications connect brands into consumer life whilst claiming further investigations. Alongside, paper attempted to investigate the use of Social media in penetrating consumer engagement within the digital context. Additionally, it examines the application of web based social media marketing strategies whilst an extended focus is made on user generated contents (UGC) and social network sites (SNS) in digital business era.  A deductive method was followed to execute a comprehensive literature review as the main research tool to build a constructive explanation. Accordingly, paper content empirical discussions published within the scopes of social media, consumer behavior and online businesses in overall. Paper discusses the key insights based on the literature review. Finally, it concludes the major thoughts of the paper whilst future research directions are suggested.  Empirical explanations are found across the markets and product contexts unveiling how digitalized media strategies connect users to integrate with brands promoted. Such studies provide arguments and directions to overview the effectiveness of new media like social media options in business perspectives. In brief, arguments are still found claiming further studies to reveal the strategic role of social media within digitalized business era. Paper highlights the possibilities of using social media as a tool enhancing consumer engagements results brand-related behaviors. Empirical insights are discussed on how user generates contents (UGC) and social network sites (SNS) could be used in marketing applications.
Application of Sample6 DETECT™ HT/L Kit for the Detection of Listeria in Mixed Leafy Greens
Authors: Arias-Rios Elba Veronica , Tenney Kristina , Mai Tam , Cantera Ruth Marie , Selover Brandon , Lorr Joseph , Davidson Seana K , Nadala Lourdes M , Samadpour Mansour
Published: July 2019

Background: Early and accurate detection of Listeria in foods is vital. Current methods require 24 h enrichment for detection. Objective: This study aimed to demonstrate enhanced early detection of Listeria in mixed leafy greens using Sample6 DETECT™ HT/L, a phage-based detection system. Methods: A method comparison between the reference method (U.S. Food and Drug Administration Bacteriological Analytical Manual Chapter 10) for the detection of Listeria spp. and the Sample6 DETECT HT/L using a new proprietary R2 Medium was performed in mixed leafy greens. Results: Using the R2 Medium enrichment with Sample6 DETECT HT/L, detection of L. innocua was possible at 12 h (with a centrifugation step), and L. monocytogenes was detected by 18 h, with equivalent performance as the 24 h enrichments using the reference method detection. The Sample6 DETECT HT/L gave an equivalent performance for L. innocua at 15 h as the reference method at 24 h. Detection was accomplished by the addition of reagents in the kit, following the package insert, and reading results in a detection chamber using a 96-well plate reader that detects a fluorescent signal. Conclusions: Results indicate the new R2 Medium and Sample6 DETECT HT/L allowed for earlier detection of Listeria spp. in mixed leafy greens. Highlights: Sample6 DETECT HT/L with the new R2 Medium allowed the early detection of Listeria spp. and may be applied in other food matrices and environmental samples.
Die hessische Landtagswahl vom 28. Oktober 2018: Fortsetzung der schwarz-grünen Wunschehe mit starken Grünen und schwacher CDU
Authors: Debus Marc , Faas Thorsten
Published: July 2019

Federal politics has often influenced elections to the Hesse state parliament . This was also true for the election 2018, which was not only decisive for the future of the incumbent black-green coalition government led by Prime Minister Volker Bouffier (CDU), but also for the fate of the federal party chairs of CDU and SPD, Angela Merkel and Andrea Nahles, at the federal level . Compared to previous election campaigns in Hesse, the 2018 campaign was less polarized, visible also in the openness of CDU, SPD, Greens and FDP in terms of forming coalition governments . The election result continued the transformation of the German party system into one with six parliamentary parties . After some vote counting problems, the incumbent coalition, which won a small parliamentary majority, was - in line with established theories of government formation - renewed . As a result of their gains in votes, the Greens’ position was stronger than five years ago, which led to more offices and to a stronger bargaining power in the coalition negotiations .
Rechtliche Regelungen des Fraktionsausschlusses im Bundestag und in den Landesparlamenten. Versuch einer Bestandsaufnahme
Authors: Leunig Sven
Published: July 2019

Expulsions of delegates from parliamentary factions are impactful, albeit rare, events . Following a discussion in the German Association for Parliamentary Affairs in 2004, the procedural rules of more than two-thirds of the parliamentary parties represented in Germany’s federal and state assemblies between February 2017 and February 2019 are examined on how such expulsions are regulated: A vast majority of parliamentary groups have made arrangements for such a case . However, significant differences persist with regard to what preconditions need to be met and what quorum is required for expulsion . From a constitutional point of view, it appears especially problematic that many parliamentary groups allow expulsions due to a loss of party membership, without mandating a formal expulsion process . Also, parliamentary groups which entered parliament in more recent years tended to have more specified rulebooks than those of more senior parties .
Fraktionsausschluss. Zum Urteil des Verfassungsgerichtshofs Rheinland-Pfalz vom 29. Januar 2019 – VGH O 18/18
Authors: Jutzi Siegfried
Published: July 2019

A member of the Rhineland-Palatine state parliament failed in his appeal to the state Constitutional Court against his expulsion from the parliamentary group AfD (Alternative for Germany) . His parliamentary group had excluded him due to his contacts to right-wing extremists . Expulsions of this type are subject to a decision by the political group assembly, which must be taken in accordance with a minimum procedure under the rule of law and must be free from arbitrariness . The Constitutional Court regarded these conditions as given and emphasized that the parliamentary group had considerable room for maneuver in this respect which is not subject to constitutional control . This applies both to the investigation and to the assessment of the facts underlying the expulsion from the group .
Psychometric properties of the satisfaction with love life among Palestinian college students
Authors: Nazzal Filasteen , Cruz Orlanda , Neto Félix
Published: July 2019

The main goal of this investigation is to examine the psychometric characteristics of the Satisfaction with Love Life Scale (SWLLS) among Palestinian college students. This scale assesses a person’s global evaluation of love satisfaction. The factorial structure, the reliability, and validity of this measure were examined. The sample included 201 college students aged 18-26 years. Confirmatory factor analysis of the SWLLS confirmed a single underlying dimension among Palestinian college students. The SWLLS evidenced satisfactory psychometric properties, with good internal consistency. Furthermore, corroboration of validity was also evidenced by means of the relationships between SWLLS score, and love status, love styles and well-being constructs. As expected, students “in love now” declared more satisfaction with love life than those “not in love now”. Erotic, pragmatic, and agapic orientations correlated significantly with the SWLLS scores. There were also significant positive correlations between the scores of the SWLLS and life satisfaction, and self-esteem. Significant negative correlations were observed between the scores of the SWLLS and loneliness. The results showed that satisfaction with love life contributes significantly and in an unique way to loneliness and self-esteem, even after controlling for participants’ sex and age. The findings of the current study suggest that the Arabic version of the SWLLS makes up a brief psychometrically sound instrument to assess love life satisfaction.
Manic episode, aggressive behavior and poor insight are significantly associated with involuntary admission in patients with bipolar disorders
Authors: Luo Chenyuli , Chen Hui , Zhong Shaoling , Guo Huijuan , Li Qiguang , Cai Weixiong , Girolamo Giovanni de , Zhou Jiansong , Wang Xiaoping
Published: July 2019

Objective(s)

Serious mental illnesses, such as bipolar disorders and schizophrenia, are closely associated with involuntary admission. Many studies have focused on involuntary admission in people with schizophrenia, but little is known about the factors associated with involuntary admission in Chinese patients with bipolar disorders. This study aimed to investigate socio-demographic and clinical factors associated with involuntary admission in Chinese patients with bipolar disorders.

Methods

In this multi-center cross-sectional survey in China, a total of 155 newly admitted patients with bipolar disorders were consecutively recruited from 16 psychiatric institutions from 15 March to 14 April, 2013. Patients’ socio-demographic and clinical data were collected from their medical records. The Modified Overt Aggression Scale and the Insight and Treatment Attitudes Questionnaire were used to measure patients’ level of aggression and insight of current psychiatric illness.

Results

The prevalence of involuntary admission was 52% in this sample of Chinese inpatients with bipolar disorders. In multiple logistic regression, a high level of aggression (odds ratio (OR) = 2.48), diagnosis of manic episode (OR = 3.65), poor insight (OR = 7.52), and a low level of education (OR = 3.13) were significantly associated with involuntary admission.

Conclusion

Manic episode, aggressive behavior, and poor insight were the significant contributing factors to involuntary admission in Chinese patients with bipolar disorders.
Rückbau eines Dükers durch die Unterelbe bei Hetlingen
Authors: Groß Thomas , Waßmuth Klaus
Published: July 2019

Im Jahr 1973 wurde für den Gastransport sowie Telekommunikationskabel ein Düker, bestehend aus drei Stahlrohren mit 700 mm Durchmesser, gebaut. Aktuell fehlte hier im Rahmen der anstehenden Elbvertiefung die nötige Überdeckung für die Betriebssicherheit des Dükers. Aus diesem Grund musste nach dem Bau eines neueren, tiefer gelegenen Dükers der alte Düker ausgebaut werden. Über die Technik und die Besonderheiten des Dükerrückbaus wird hier berichtet. Die Bauaufgabe war einmalig und neu. Sie stellte die Planung und Ausführung vor große Herausforderungen.
A four‐stage longitudinal study exploring pupils’ experiences, preparation and support systems during primary–secondary school transitions
Authors: Jindal‐Snape Divya , Cantali Dianne
Published: July 2019

A longitudinal study was conducted over four stages of three school years across the primary–secondary transition. The purpose was to understand the dynamic transition experience of pupils, investigate the effectiveness of preparation by schools to support transitions and understand pupils’ most important support networks. Using online questionnaires, data were collected from pupils at four time points, twice from secondary school professionals and their parents, and once from primary school professionals. Results highlight the ongoing and dynamic nature of transitions. What pupils were excited about were still seen to be good once they were in secondary school, and aspects that worried them declined over time. Some pupils experienced problems and adapted at different times, whereas for some, problems emerged later. It seems that those who anticipated problems when in primary school were more likely to experience problems; this has implications for the discourse around transitions and its impact on pupils’ anticipation of transition experience. Although transition planning and preparation by schools were important and varied, they were not always effective, not provided in a timely manner and did not tap into their naturally occurring support networks in the home and community. This study makes unique contributions in terms of highlighting the dynamic transitions process and change in pupils’ experience over time; various aspects of transitions that children are excited and concerned about and how these changed over time; professionals’ conceptualisations of transitions; pupils’ and parents’ views of the effectiveness of transition practices at various stages; and pupils’ real support networks.