Faster Development of AUTOSAR compliant ECUs through simulation

International audienceVirtualization allows the simulation of automotive ECUs on a Windows PC executing in a closed-loop with a vehicle simulation model. This approach enables moving many development tasks from road or test rigs and HiL (Hardware in the loop) to PCs, where they can often be performed faster and cheaper. Technical challenge: How to port ECU tasks and basic software to Windows PC with reasonable effort, so that key development tasks can be performed on a PC, without the need of accessing real hardware such as vehicle prototypes, test rigs or HiL facilities. This paper presents a new solution for the use case of ECUs developed within the emerging AUTOSAR standard: First, the AUTOSAR authoring tool AUTOSAR Builder (Dassault Systèmes) is used to design the application software and system aspects of a single ECU or an distributed embedded system which is then stored as AUTOSAR XML descriptions. The application code can either be developed in the AUTOSAR Builder environment or auto-generated by tools such as Embedded Coder (MathWorks), TargetLink (dSPACE) or Ascet (ETAS). Once tested in AUTOSAR Builder, selected software components or compositions can be exported including an AUTOSAR OS (Operating System) and RTE (Run- Time Environment) as an FMU (Functional Mockup Unit). FMU [4] is a new exchange format for models that has been developed in the EU-funded MODELISAR project (2008 - 2011) and since then gained considerable acceptance across multiple industries and tools. The FMU can then be imported into the virtual ECU tool Silver (QTronic), where it can be co-simulated with vehicle models originating from a wide range of simulation tools, including Dymola, SimulationX, MapleSim and AMESim. Vehicle models are again provided as FMUs, or via proprietary binary export formats, typically Windows DLLs. Tools for measurement and calibration such as CANape (Vector Informatik) or INCA (ETAS) can then be connected to the virtual ECU running on PC, to directly measure or tune its parameters, like an engineer would do in a real car. Virtual ECUs are also used to move testing activities from test rigs and HiLs to Windows PC

Tunnel magnetoresistance in alumina, magnesia and composite tunnel barrier magnetic tunnel junctions

Using magnetron sputtering, we have prepared Co-Fe-B/tunnel barrier/Co-Fe-B magnetic tunnel junctions with tunnel barriers consisting of alumina, magnesia, and magnesia-alumina bilayer systems. The highest tunnel magnetoresistance ratios we found were 73% for alumina and 323% for magnesia-based tunnel junctions. Additionally, tunnel junctions with a unified layer stack were prepared for the three different barriers. In these systems, the tunnel magnetoresistance ratios at optimum annealing temperatures were found to be 65% for alumina, 173% for magnesia, and 78% for the composite tunnel barriers. The similar tunnel magnetoresistance ratios of the tunnel junctions containing alumina provide evidence that coherent tunneling is suppressed by the alumina layer in the composite tunnel barrier.Comment: 3 pages,4 figures, 1 tabl

Composition and electronic structure of SiOx/TiOy/Al passivating carrier selective contacts on n-type silicon solar cells

Carrier-selective and passivating SiOx/TiOy heterocontacts are an attractive alternative to conventional contacts due to their high efficiency potentials combined with relatively simple processing schemes. It is widely accepted that post deposition annealing is necessary to obtain high photovoltaic efficiencies, especially for full area aluminum metallized contacts. Despite some previous high-level electron microscopy studies, the picture of atomic-scale processes underlying this improvement seems to be incomplete. In this work, we apply nanoscale electron microscopy techniques to macroscopically well-characterized solar cells with SiOx/TiOy/Al rear contacts on n-type silicon. Macroscopically, annealed solar cells show a tremendous decrease of series resistance and improved interface passivation. Analyzing the microscopic composition and electronic structure of the contacts, we find that partial intermixing of the SiOx and TiOy layers occurs due to annealing, leading to an apparent thickness reduction of the passivating SiOx. However, the electronic structure of the layers remains clearly distinct. Hence, we conclude that the key to obtain highly efficient SiOx/TiOy/Al contacts is to tailor the processing such that the excellent chemical interface passivation of a SiOx layer is achieved for a layer thin enough to allow efficient tunneling through the layer. Furthermore, we discuss the impact of aluminum metallization on the above mentioned processes

Nanofabrication of spin-transfer torque devices by a PMMA mask one step process: GMR versus single layer devices

We present a method to prepare magnetic spin torque devices of low specific resistance in a one step lithography process. The quality of the pillar devices is demonstrated for a standard magnetic double layer device. For single layer devices, we found hysteretic switching and a more complex dynamical excitation pattern in higher fields. A simple model to explain the resistance spikes is presented.Comment: 22 pages, 6 figures, submitted to J. Appl. Phy

Plasma Profiling Time-of-Flight Mass Spectrometry for Fast Elemental Analysis of Semiconductor Structures with Depth Resolution in the Nanometer Range

Plasma profiling time of flight mass spectrometry (PP-TOFMS) has recently gained interest, as it enables the elemental profiling of semiconductor structures with high depth resolution in short acquisition times. As recently shown by Tempez et al., PP-TOFMS can be used to obtain the composition in the structures for modern field effect transistors [1]. There, the results were compared to conventional SIMS measurements. In the present study, we compare PP-TOFMS measurements of an Al-/In-/GaN quantum well multi stack to established micro- and nano-analysis techniques like cathodoluminescence (CL), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). We show that PP-TOFMS is able to resolve the layer structure of the sample even more than 500 nm deep into the sample and allows the determination of a relative elemental composition with an accuracy of about 10 rel. %. Therefore, it is an extremely rapid alternative method to obtain semiconductor elemental depth profiles without expensive and time consuming sample preparation as it is needed for TEM. Besides, PP-TOFMS offers better depth resolution and more elemental information than for example electrochemical capacitance-voltage (ECV), as the acquisition of all elements occurs in parallel and not only electrically (ECV) or optically (CL) active elements are observed