| 41. |
- Abermann, S., et al.
(författare)
-
Processing and evaluation of metal gate/high-k/Si capacitors incorporating Al, Ni, TiN, and Mo as metal gate, and ZrO2 and HfO2 as high-k dielectric
- 2007
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 84:5-8, s. 1635-1638
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Tidskriftsartikel (refereegranskat)abstract
- We evaluate various metal gate/high-k/Si capacitors by their resulting electrical characteristics. Therefore, we process MOS gate stacks incorporating aluminium (Al), nickel (Ni), titanium-nitride (TiN), and molybdenum (Mo) as the gate material, and metal organic chemical vapour deposited (MOCVD) ZrO2 and HfO2 as the gate dielectric, respectively. The influence of the processing sequence - especially of the thermal annealing treatment - on the electrical characteristics of the various gate stacks is being investigated. Whereas post metallization annealing in forming gas atmosphere improves capacitance-voltage behaviour (due to reduced interface-, and oxide charge density), current-voltage characteristics degrade due to a higher leakage current after thermal treatment at higher temperatures. The Flatband-voltage values for the TiN-, Mo-, and Ni-capacitors indicate mid-gap pinning of the metal gates, however, Ni seems to be thermally unstable on ZrO2, at least within the process scheme we applied.
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| 42. |
- Abid, Jean-Pierre, et al.
(författare)
-
Controlled reversible adsorption of core : Shell metallic nanoparticles at the polarized water/1,2-dichloroethane interface investigated by optical second-harmonic generation
- 2007
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 111:25, s. 8849-8855
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Tidskriftsartikel (refereegranskat)abstract
- We report the observation of the reversible adsorption of core-shell gold-silver nanoparticles at the polarized water/1,2-dichloroethane interface using the nonlinear optical technique of surface second-harmonic generation. This study unambiguously demonstrates the excellent stability against aggregation of these core-shell nanoparticles, namely, gold core nanoparticles coated with silver layers of variable thickness, in the presence of an electrolyte salt like lithium chloride. Furthermore, it is also demonstrated that the adsorption of the nanoparticles is reversible by modulating the applied potential at water/1,2-dichloroethane interface. The analysis of these results is performed within the Debye-Huckel approximation of the electrostatic interactions between the nanoparticles. This approach shows that the stability of core-shell nanoparticles can be attributed to the formation of a silver oxide layer at the Surface of the particles.
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| 43. |
- Abom, A.E., et al.
(författare)
-
Characterization of the metal-insulator interface of field-effect chemical sensors
- 2003
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 93:12, s. 9760-9768
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Tidskriftsartikel (refereegranskat)abstract
- The metal-insulator interface of hydrogen-sensitive metal-insulator-semiconductor capacitors, with SiO2 as the insulator and Pt as the metal contact, was discussed. It was found that the difference in hydrogen response between differently prepared devices was explained by a difference in concentration of available adsorption sites. The analysis showed that the concentration of Pt atoms in contact with the oxide affected both the hydrogen response and the metal-oxide adhesion.
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| 44. |
- Abom, A.E., et al.
(författare)
-
Experimental evidence for a dissociation mechanism in NH3 detection with MIS field-effect devices
- 2003
-
Ingår i: Sensors and actuators. B, Chemical. - 0925-4005 .- 1873-3077. ; 89:1-2
-
Tidskriftsartikel (refereegranskat)abstract
- The gas response mechanism of ammonia detection with Pt-based metal-insulator-semiconductor (MIS) field-effect sensors was investigated. An experimental model system was designed which compares the responses of thick continuous Pt layers with controlled morphology and surface chemical composition, with the response of thin, discontinuous layers. The surface of a thick, continuous sputter-deposited Pt film is modified, either by (i) the deposition of a thin SiO2 overlayer, (ii) reactive sputter deposition of PtOx, or (iii) co-deposition of Pt with SiO2 in Ar + O2 atmospheres. We show that the ammonia response is caused by the formation of atomic hydrogen through the dissociation of NH3 at temperatures <200 °C. It is found that the modified surfaces exhibit increased ammonia selectivity compared to a pure Pt film. Results from this work indicate that the reason for the changed selectivity is the appearance of an oxidized PtOx phase or triple phase boundaries between Pt, SiO2 and the ambient gas, rather than for solely morphological reasons. © 2002 Elsevier Science B.V. All rights reserved.
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| 45. |
- Abom, A.E., et al.
(författare)
-
Influence of gate metal film growth parameters on the properties of gas sensitive field-effect devices
- 2002
-
Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 409:2, s. 233-242
-
Tidskriftsartikel (refereegranskat)abstract
- Thin films of Pt have been grown as gate metals on the oxide surface of gas sensitive field-effect devices. Both electron beam evaporation and dc magnetron sputtering has been used. The energy of the impinging Pt atoms, the substrate temperature and the thickness of the Pt film were used as parameters in this study. The influence of the growth parameters on the gas response has been investigated and compared with the properties of the films, studied by transmission electron microscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The conditions during growth of the Pt film are found to have a large impact on the properties of the device. As expected, crystallinity, morphology and the metal/substrate interfacial structure are also affected by processing parameters. Three different growth processes stand out as the most promising from gas sensor considerations, namely room temperature evaporation, sputtering at high pressures and sputtering at high temperatures. The correlation between gas responses and properties of the gas sensitive layer is discussed. © 2002 Elsevier Science B.V. All rights reserved.
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| 46. |
- Abom, A.E., et al.
(författare)
-
Thin oxide films as surface modifiers of MIS field effect gas sensors
- 2002
-
Ingår i: Sensors and actuators. B, Chemical. - 0925-4005 .- 1873-3077. ; 85:1-2, s. 109-119
-
Tidskriftsartikel (refereegranskat)abstract
- The catalytic activity at the surface of Pt based MIS field effect gas sensors is modified by the deposition of thin films of SnO2, Al2O3 and SiO2, grown by reactive sputtering. It is found that a very thin layer (<10 nm) of SiO2 and SnO2 changes the catalytic activity towards higher NH3 selectivity, but with thicker films the sensor response vanishes. Since the response mechanism for these sensors is dependent on dissociation of molecules, it is likely that at low temperatures (140 °C), neither dissociation on nor transport/diffusion through the thicker films takes place. However, with Pt in conjunction with SiO2 or SnO2, the surface reactions will be altered, with enhanced NH3 selectivity as a result. A thin film of Al2O3, on the other hand, has a much smaller influence on the gas response to the test gases used in this work. Furthermore the sputtering process is found to strongly influence the sensor responses, and specifically reduce the sensitivity of the sensor. A thin intermediate layer of evaporated Pt does not completely protect the underlying structure from sputter induced damage. © 2002 Elsevier Science B.V. All rights reserved.
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| 47. |
- Abrahamsson, Johan, et al.
(författare)
-
Magnetic bearings in kinetic energy storage systems for vehicular applications
- 2011
-
Ingår i: Journal of Electrical Systems. - 1112-5209. ; 7:2, s. 225-236
-
Tidskriftsartikel (refereegranskat)abstract
- The rotating Kinetic Energy Storage System (KESS) is suitable as temporary energy storage in electric vehicles due to its insensitivity to the number of charge-discharge cycles and its relatively high specific energy. The size and weight of the KESS for a given amount of stored energy are minimized by decreasing the moment of inertia of the rotor and increasing its speed. A small and fast rotor has the additional benefit of reducing the induced gyroscopic moments as the vehicle turns. The very high resulting rotational speed makes the magnetic bearing an essential component of the system, with the Active Magnetic Bearing (AMB) being the most common implementation. The complexity and cost of an AMB can be reduced by integration with the electric machine, resulting in a bearingless and sensorless electric machine. This review article describes the usage of magnetic bearings for FESS in vehicular applications.
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| 48. |
- Abrahamsson, Johan, et al.
(författare)
-
Prototype of electric driveline with magnetically levitated double wound motor
- 2010
-
Ingår i: Electrical Machines (ICEM), 2010 XIX International Conference on.
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the ongoing work of constructing a complete driveline for an electric road vehicle, using a flywheel as auxiliary energy storage. The flywheel energy storage system (FESS) is connected in series between the main energy storage (batteries) and the wheel motor of the vehicle, allowing the batteries to deliver power to the system in an optimized way, while at the same time making efficient use of regenerative braking. A double wound permanent magnet electric machine is used to electrically separate the two sides. In order to minimize losses, the machine has a double rotor configuration and is suspended with magnetic bearings. A bench test set-up is being constructed to investigate the properties of this system in detail. This set-up will achieve a level of power and energy close to that of a full scale system. This will allow measurements of complete drive cycles to be performed, improving the understanding of the constituting components and optimization of the complete system.
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| 49. |
- Abrahamsson, Mats, et al.
(författare)
-
Dynamic effectiveness : Improved industrial distribution from interaction between marketing and logistics strategies
- 2005
-
Ingår i: Journal of Marketing Channels. - 1046-669X .- 1540-7039. ; 12:2, s. 83-112
-
Tidskriftsartikel (refereegranskat)abstract
- Based on different observations, in theory as well as in practice, we have identified strategies and operations following two different tracks, striving in different directions, despite it being well known they should go hand in hand. For companies challenged by a more and more dynamic business environment with heavier market segmentation, additional marketing channels, increasing globalisation on supplier and customer side, and high pressure on profit margins, the result from this is competitive weakness. The purpose of this article is to switch focus from operational effectiveness and strategic positioning as static success concepts on how to improve industrial distribution, to dynamic challenges of how to continuously manage the interaction between marketing strategies and operations (e.g., logistics) under the influence of a dynamic business environment. From theories in market strategies, logistics, flexibility, and marketing channels together with empirical experience from a best practice case study, we are introducing a model for dynamic effectiveness, describing the different characteristics of a company and what to focus on in order to become more dynamic. In order to constantly move to new market positions, and at the same time, restructure logistics and improve operational effectiveness, we have identified the dynamic capabilities of an organisation to be the key to success in industrial distribution. We define dynamic effectiveness as "how fast-and-well a company can go from one strategic positioning and productivity frontier to another." It tells that a frequent interaction between new strategic moves and actions for higher operational effectiveness is required to be in pace with the dynamic and changing business environment and to stay ahead of competition. As a part, of this, best, practice logistics performance makes it possible not only to be more agile to new strategic moves, but also to drive strategic development from a high operational level. This is achieved by designing logistics to be a resource base to support and be an enabler for new strategic moves on the market. © 2004 by The Haworth Press, Inc. All rights reserved.
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| 50. |
- Abrahamsson, R., et al.
(författare)
-
Elimination of leakage and ground-bounce effects in ground-penetrating radar data
- 2001
-
Ingår i: Proceedings of the 11th IEEE Signal Processing Workshop on Statistical Signal Processing, 2001. - 0780370112 ; , s. 150-153
-
Konferensbidrag (refereegranskat)abstract
- We address the problem of removing specular ground surface reflections and leakage/cross-talk from downward looking stepped frequency ground-penetrating radar (GPR) data. A new model for the ground-bounce and the leakage/cross-talk is introduced. An algorithm that jointly estimates these effects from collected data is presented. The algorithm has the sound foundation of a nonlinear least squares (LS) fit to the presented model. The minimization is performed in a cyclic manner where one step is a linear LS minimization and the other step is a non-linear LS minimization where the optimum can efficiently be found using, e.g., the chirp-transform algorithm. The results after applying the algorithm to measured GPR data, collected at a US army test range, are also shown
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