Electrical characterization of high k-dielectrics for 4H-SiC MIS devices

We report promising results regarding the possible use of AlN or Al 2 O 3 as a gate dielectric in 4H-SiC MISFETs. The crystalline AlN films are grown by hot wall metal organic chemical vapor deposition (MOCVD) at 1100 \ub0C. The amorphous Al 2 O 3 films are grown by repeated deposition and subsequent low temperature (200 \ub0C) oxidation of thin Al layers using a hot plate. Our investigation shows a very low density of interface traps at the AlN/4H-SiC and the Al 2 O 3 /4H-SiC interface estimated from capacitance-voltage (CV) analysis of MIS capacitors. Current-voltage (IV) analysis shows that the breakdown electric field across the AlN or Al 2 O 3 is ∼ 3 MV/cm or ∼ 5 MV/cm respectively. By depositing an additional SiO 2 layer by plasma enhanced chemical vapor deposition at 300 \ub0C on top of the AlN or Al 2 O 3 layers, it is possible to increase the breakdown voltage of the MIS capacitors significantly without having pronounced impact on the quality of the AlN/SiC or Al 2 O 3 /SiC interfaces

Использование принципа клиентоориентированности при формировании стратегии развития предприятий

Материалы межвуз. науч. конф. студентов, магистрантов и аспирантов, Гомель, 15 мая 2008 г

Targeted Energy Transfer in Bose-Einstein Condensates

Targeted Energy Transfer is a resonance phenomenon in coupled anharmonic oscillators. In this thesis we investigate if the concept of Targeted Energy Transfer is applicable to Bose-Einsteain condensates in optical lattices. The model used to describe Bose-Einstein condensates in optical lattices is based on the Gross-Pitaevskii equation. Targeted Energy Transfer in these systems would correspond to energy being transferred from one lattice site to another. We also try to expand the concept of Targeted Energy Transfer to a system consisting of three sites, where one of the sites are considered a perturbation to the system. We have concluded that it is possible to achieve Targeted Energy Transfer in a three-site system. The set-up of the system will in some of the cases studied lead to interesting properties, such as more energy being transferred to the acceptor site than what was initially localized on the donor site

Exploiting and defending open digital platforms with boundary resources

Digital platforms can be opened in two ways to promote innovation and value generation. A platform owner can open access for third-party participants by establishing boundary resources, such as APIs and an app store, to allowcomplements to be developed and shared for the platform. Furthermore, to foster cooperation with the complementors, the platform owner can use an open-source license boundary resource to open and share the platform's core resources. However, openness that is too wide renders the platform and its shared resources vulnerable to strategic exploitation. To our knowledge, platform strategies that promote such negative outcomes have remained unexplored in past research. We identify and analyze a prominent form of strategic exploitation called platformforking in which a hostile firm, i.e., a forker, bypasses the host's controlling boundary resources and exploits the platform's shared resources, core and complements, to create a competing platform business. We investigate platform forking on Google's Android platform, a successful open digital platform, by analyzing the fate of five Android forks and related exploitative activities. We observe several strategies that illustrate alternative ways of bundling a platform fork from a set of host, forker, and other resources. We also scrutinize Google's responses, which modified Android's boundary resources to curb exploitation and retain control. In this paper, we make two contributions. First, we present a theorization of the competitive advantage of open digital platforms and specifically expose platform forking as an exploitative and competitive platform strategy. Second, we extend platform governance literature by showing how boundary resources, which are mainly viewed as cooperative governance mechanisms, are also used to combat platform forking and thus sustain a platform's competitive advantage.Peer reviewe

The Origin and Formation Mechanism of an Inclined Line-like Defect in 4H-SiC Epilayers

The origin and the formation mechanism of a surface morphological defect in 4H-SiC epilayers are reported. The defect appears on the surface of an epilayer as an inclined line-like feature at an angle of +/- 80 degrees to the step-flow direction [ 11 2 over bar 0 ] . The defect is confirmed to originate from a threading screw dislocation intersecting the surface and its orientation is controlled by the sign of the Burgers vector of the dislocation. The defect forms through the interaction of local spiral growth associated with threading screw dislocations and step-flow growth related to the substrate offcut. The defect mainly appears in the epilayers grown through chloride-based chemistry, where in situ surface preparation of the substrate is performed in H-2 + HCl at a relatively high temperature.Funding Agencies|Swedish Energy Agency Energimyndigheten project [43611-1]</p

Wafer Scale On-Axis Homoepitaxial Growth of 4H-SiC(0001) for High-Power Devices: Influence of Different Gas Phase Chemistries and Growth Rate Limitations

On-axis homoepitaxy of 4H-SiC has the advantage of producing epilayers that are free of basal plane dislocations. Such layers can be highly beneficial for SiC-based high-power bipolar electronic devices which otherwise suffer from bipolar degradation phenomena related to basal plane dislocations in epilayers. In this study, we have developed on-axis homoepitaxy on the Si-face of 100 mm diameter 4H-SiC wafers with only 4H polytype in the epilayer excluding the edges of the wafer. We have also compared standard and chloride-based growth, the influence of different ambient conditions on surface preparation of the substrate, the influence of the histories of different growth cells, and the geometry of the susceptors regarding 4H-polytype stability in the epilayer. Substrate surface preparation, growth temperature, C/Si ratio, and Si/H ratio are found to be the most influential parameters to achieve homoepitaxy. On-axis homoepitaxial growth rate is limited to a very low value of amp;lt;10 mu m/h. We have performed a systematic study to understand the influence of different growth parameters and gas phase chemistries to determine whether on-axis growth rate can be enhanced and, if not, what the limiting factors are. Our experimental evidence suggests that the on-axis growth rate is not limited by the gas phase chemistry or diffusion, but it is limited by the surface kinetics. A significantly low step density on on-axis substrates lowers the surface reaction rates and limits the growth rate to lower values. It may not be possible to further improve the growth rate even with chloride-based growth using epitaxial growth conditions.Funding Agencies|Swedish Energy Agency Energimyndigheten Project [43611-1]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Electronic Component Systems for European Leadership Joint Undertaking under Project OSIRIS [662322]</p

QA and Enhancement Marketplace for HEIs – An Erasmus+ project

International audienceImproving European education and training system quality has been set as a key target in Europe's strategy to become a smart, sustainable and inclusive economy by 2020 (European Commission 2010). These objectives are more specifically defined in the so called Modernisation Agenda (European Commission 2011). More specifically it sets a goal to improve the quality and relevance of higher education. In this process external evaluation and self-assessment are seen in a key role! In the CDIO approach the 12 CDIO standards provide a framework for continuous improvement. Each institution/institutional department are encouraged to regularly do the self-evaluation using the CDIO Standards. Eight European universities identified a need for further enhancement of the self-evaluations and creation of processes with peers to reduce the inertia of heavy accreditations/evaluations in HEIs. In September 2014 these universities started an Erasmus+ project (QAEMarketPlace4HEI) aiming at (1) Developing a collaborative, comprehensive and accessible evaluation process model, methods and tools for HEIs to complement the accreditation systems; (2) Promoting, increasing and exploiting further the European collaboration in the evaluation processes and the exchange of best practices; (3) Disseminating the model, best practices and widen the cooperation to new HEIs in Europe through the partner networks

Four Tactics for Implementing a Balanced Digital Platform Strategy

Digital platforms, such as Apple’s iOS and Google’s Android, face two major challenges in maintaining their competitive positions. First, the ever-increasing variety of thirdparty apps risks fragmenting a platform and requires the platform owner to use controls to maintain platform unity. Second, a too-open approach may invite competitors to exploit a platform. A balanced digital platform strategy requires a platform owner to deploy four tactics—leverage, control, exploit, and defense—to make the necessary trade-offs between variety and unity, and open and closed