Fraunhofer-Publica
The Fraunhofer-Publica has been successfully documenting the research results of the Fraunhofer-Gesellschaft for over 30 years. The platform enables the collaborative linking of research-relevant objects and disseminates within the international scientific community.
The Fraunhofer-Publica thus fulfils its responsibility to promote the transfer of knowledge and know-how to industry and society.
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Research outputs
As an application-oriented research organisation, Fraunhofer aims to conduct highly innovative and solution-oriented research - for the benefit of society and to strengthen the German and European economy.
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Projects
Fraunhofer is tackling the current challenges facing industry head on. By pooling their expertise and involving industrial partners at an early stage, the Fraunhofer Institutes involved in the projects aim to turn original scientific ideas into marketable products as quickly as possible.
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Researchers
Scientific achievement and practical relevance are not opposites - at Fraunhofer they are mutually dependent. Thanks to the close organisational links between Fraunhofer Institutes and universities, science at Fraunhofer is conducted at an internationally first-class level.
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Institutes
The Fraunhofer-Gesellschaft is the leading organisation for applied research in Europe. Institutes and research facilities work under its umbrella at various locations throughout Germany.
Recent Additions
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PublicationComparison of aluminum nitride thin films prepared by magnetron sputter epitaxy in nitrogen and ammonia atmosphere( 2024)Wurtzite-type aluminum nitride (AlN) thin films exhibiting high thermal conductivity, large grain size, and low surface roughness are desired for both bulk acoustic wave and surface acoustic wave resonators. In this work, we use ammonia (NH(3)) assisted reactive sputter deposition of AlN to significantly improve these properties. The study shows a systematic change in the structural, thermal, and morphological properties of AlN grown in nitrogen (N(2)) and N(2) + NH(3) atmosphere. The study demonstrates that NH(3) assisted AlN sputtering facilitates 2D growth. In addition, the study presents a growth model relating the 2D growth to improve the mobility of aluminum (Al) and nitrogen (N) ad-atoms in NH(3) atmosphere. Consequently, the thermal conductivity and roughness improve by ≈76%, and ≈35%, while the grain size increases by ≈78%.
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PublicationTwo-dimensional electron gases in AlYN/GaN heterostructures grown by metal-organic chemical vapor deposition( 2024)Wurtzite AlN alloyed with group 3 elements Sc and Y boosts the performance of GaN-based high-electron-mobility transistors (HEMTs) significantly as they increase the spontaneous polarization of the barrier layer and, thus, enhance the charge carrier density ns in the two-dimensional electron gas (2DEG) formed at the interface with the GaN channel. The emerging nitride Al1−xYxN additionally features an a lattice parameter matching to that of GaN at x = 0.07–0.11, allowing for the growth of strain-free barriers. Here, we demonstrate the growth of Al1−xYxN/GaN heterostructures for HEMTs by metal–organic chemical vapor deposition for the first time. The effect of the Y concentrations on the 2DEG is investigated in a Y concentration range from 3% to 15%. At 8% Y, a record mobility of 3200 cm2/(Vs) was measured at a low temperature (7 K). Room and low-temperature ns was at 1–2 × 1013 cm−2. Al0.92Y0.08N barriers were coherently strained to the GaN channel for barrier thicknesses from 5 to 15 nm. Finally, the deposition of Al1−xYxN/GaN heterostructures deposited on 4″ 4H–SiC wafers had a room-temperature mobility close to 1400 cm2/(Vs). AlYN/GaN heterostructures may offer advantages over AlScN/GaN heterostructures not only for the lower price and higher abundance of the raw material but also in terms of electrical characteristics and may be more suitable for power amplifying applications due to increased electron mobility.
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PublicationTowards Hybrid Computer Vision: Assurance of Deep Learning based Environmental Perception with traditional Computer Vision in Advanced Air Mobility( 2024-05-27)The application of autonomous unmanned aerial vehicles (UAVs) within the Advanced Air Mobility (AAM) vision has the potential to significantly contribute to the resolution of several challenges in the fields of transportation, logistics, industrial automation and space travel. In order to enable the safe and large scale deployment of autonomous UAVs, it is crucial to ensure a trustworthy perception of the environment. The complexity of environmental perception necessitates the utilization of deep learning (DL) solutions, which are characterized by their opacity and lack of traceability in decision-making processes. Given these considerations, there have already been first regulatory initiatives from the EU and EASA that require conceptual safeguards for DL based environmental perception. The Group of Highly Automated Flying at the Fraunhofer Institute for Transportation and Infrastructure Systems IVI in Ingolstadt is therefore conducting research into the development of trustworthy environmental perception as part of the VERUM research project, in which this master thesis is conceptually integrated. This thesis explores the potential of employing a framework based on traditional computer vision (CV) methods to assure the trustworthiness of DL based environmental perception for AAM. The aim of the framework is to utilize traditional CV methods, which enable the detection of matches or mismatches in the output of DL models and subsequent condence adjustments. By avoiding these potentially untrustworthy areas, accidents could be prevented and human lives could be protected in downstream decision-making processes. In the initial conceptualization phase, a comprehensive literature survey was conducted to identify traditional CV methods as potential candidates to assure semantic and topological DL model outputs. These traditional CV methods were further analyzed to design and develop approaches to assure these DL models. The results serve as the foundation for the subsequent design and implementation of the framework "Hybrid Computer Vision". The prototype of the developed framework was evaluated and examined to determine the extent to which trustworthy and untrustworthy areas were recognized in the environmental perception and assigned with increased or decreased confidence, respectively. The findings of this thesis demonstrate the capability to assure DL based environmental perception with traditional CV, thereby representing a first concrete solution to the conceptual regulations.
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PublicationEntwicklung und Anwendung einer Methode zur Bewertung der Plausibilität und Qualität von Unfallszenarien der TASC-Datenbank( 2024-05)Die vorliegende Arbeit beschreibt die Entwicklung einer Methode zur Bewertung der Plausibilität und Qualität von simulierten Unfallszenarien aus der TASC-Datenbank. Der erste Teil der Arbeit legt die theoretischen Grundlagen dar und beleuchtet den Entstehungsprozess der relevanten Daten, um mögliche Fehler und Ungenauigkeiten zu identifizieren. Bislang beschränkt sich die Qualitätsbewertung auf vereinzelt im Entstehungsprozess der TASC-Daten verankerten Mechanismen. Diese umfassen die Bewertung der Skizzenpräzision durch den Zeichner und die Einschätzung des Übereinstimmungsgrades der Referenzfälle über das GIDAS-Level. Nach der Simulation werden Plausibilitätsprüfungen, einschließlich Querbeschleunigungs- und Kollisionsprüfungen, durchgeführt, wobei unplausible Fälle aussortiert werden. Eine umfassende Bewertungsmethode der vollständigen TASC-Daten besteht derzeit noch nicht. Die vorliegende Arbeit soll einen ersten Schritt leisten, um eine umfassende Bewertung der TASC-Daten zu etablieren. Die konzipierten Bewertungsparameter umfassen im Wesentlichen die Abweichungen zwischen den vorgegeben und de simulierten Pfaden der Beteiligten sowie die diskreten Abstände und die zeitlichen Differenzen der Kollision. Der entwickelte Maßstab zur Einschätzung der Qualität der Parameterwerte beruht auf gruppenspezifischer statistischer Auswertung der Verteilung der Parameterwerte. Somit entsteht eine dynamische Bewertung der Daten durch die Individualisierung des Bewertungsmaßstabes. Die Umsetzung der Bewertungsmethode gelingt durch einen Programmcode in der Programmiersprache R, welcher es ermöglicht eine große Anzahl von Fällen in wenigen Sekunden auszuwerten.
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PublicationQualitative evaluation of flip chip solder bumps produced by stencil printing of solder paste on various electroless nickel/gold metallizations( 2006)Stencil printing of solder paste in conjunction with electroless Ni/Au UBM on Al metallization offers the most economical method for wafer bumping either for Flip chip applications or for WLCSP packages. This paper deals in detail with the bumping process of 6? wafers at 300µm and 200µm pitch and investigates the bump interface integrity for different Au flash thicknesses on 5µm Ni. The bump height produced is 108±5µm with Sn63Pb37 and Sn4Ag0.5Cu compositions. Bumped chips have undergone high temperature storage at 150oC and up to 10 multiple reflow passes. Interesting results show that the shear strength of bumps with 5µmNi/26nmAu/Sn4Ag0.5Cu interface is about 97.1±8.3 MPa; very close to the standard 5µmNi/80nmAu UBM used so far in electroless processes. Furthermore, Sn4Ag0.5Cu bumps with only 5µm Ni UBM (without flash Au) has shown significant shear strength of about 80.4 ± 8.9 MPa which corresponds to about 17% reduction in strength. The prevailing shear fracture mode for all bumped chips is solder bulk fracture. The results imply that a possible reduction in Au flash thickness or a complete absence of Au can be potentially applied without any compromise in the mechanical integrity and robustness of the bumps.
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PublicationAlgorithm for the Automatic Verification of Complex Mixed-Signal ICs regarding ESD-Stress( 2005)In this publication, an algorithm is described which automates the verification of a com¬p¬lex integrated circuit (IC) with regard to the behavior under transient high voltage impulses (e.g. ESD). Here, the complexity of the whole circuit diagram is being reduced in a first step in order to carry out a transient simulation with high current simulation models time-efficiently in a second step. The nowadays usual manual extraction of the relevant circuit parts for such a transient analysis is then automated and therefore, the error susceptibility of this process is minimized as well. The algorithm is embedded in a commercial design frame¬work for IC-design and uses the data structures already existing.