The accelerated processes in vehicle development require new technologies for function development and validation. With this motivation, Function-in-the-Loop (FiL) simulation was developed as a link between Software-in-the-Loop (SiL) and Hardware-in-the-Loop (HiL) simulation. The combination of real Electronic Control Unit (ECU) hardware and software in conjunction with virtual components is very well suited for function development and testing. This approach opens up new possibilities for mechatronic systems that would otherwise require special test benches. For this reason, an Electric Power Steering (EPS) was transferred to a virtual environment using FiL simulation. This enables a wide range of applications, from EPS testing to the development of connected driving functions on an integrated platform. Right from the early development phases, the technology can be used purposefully with short integration cycles. Throughout the entire development process, function development and validation can be effectively controlled and quality increased.

Three-dimensional GaN microand nanorods with high aspect ratio have recently gained substantial interest in LED research, due to their reduced defect density, their non-polar sidewalls and their increased active area. Here, we present an alternative geometry for high aspect ratio 3D nanostructures: vertically standing GaN “walls”, so called GaN fins. With high aspect ratios, these GaN fins exhibit the same interesting characteristics as their rod counterparts mentioned above. Beyond that, due to their geometry, the respective material analysis and device https://doi.org/10.24355/dbbs.084-201912181044-0 2 processing can be expected to be less complex. We are able to demonstrate the highly reproducible selective area growth of these fins by continuous mode MOVPE. Fin heights of more than 50 μm (aspect ratios of nearly 14) could be achieved and growth rates are as high as 22.8 μm/h in the beginning of the growth. The sidewalls are smooth non-polar <11-20> a-planes, suitable for optoelectronic devices due to the missing quantum-confined Stark effect and less edge effects compared to rods. We investigate the influence of pattern orientation and geometry on the fin morphology. Moreover, the influence of silane flow, which is known to enhance the vertical growth rate, and other growth parameters are systematically explored. INTRODUCTION GaN is the material of choice for solid state lighting since many years. Conventional light emitting diodes (LEDs) based on the (Al,In,Ga)N material system are generally grown in a planar geometry using c-oriented thin film deposition. These planar GaN, AlGaN and InGaN films are characterized by a huge density of threading dislocations due to lattice mismatch to each other and to the underlying growth substrate, typically sapphire, SiC or silicon. The polar c-orientation of the layers leads to high piezoelectric fields in the multi quantum well (MQW) region. In spite of these properties, very high quantum efficiencies can be reached in LEDs for certain indium concentrations, but both high defect density and piezoelectric effects are viewed as being disadvantageous for certain applications like laser diodes or higher indium content quantum wells. The m-plane quantum wells of three-dimensional (3D) microor nanorods in a core-shell geometry are both defect free and free of piezoelectric effects1. In addition, the large sidewall surface allows for increasing the light emitting area of LED devices without increasing the necessary substrate area2, potentially reducing production cost per lumen substantially and increasing the luminous density. https://doi.org/10.24355/dbbs.084-201912181044-0 3 Three-dimensional (3D) GaN structures are usually either directly grown by MOVPE in a selective area growth (SAG) process in order to reduce the dislocation density due to the small footprint3, or deep etched into a GaN thin film in order to release its strain4. 3D n-GaN structures have already been used as the basis for core-shell LEDs with MQW and p-GaN shell layers5. These QWs do not exhibit the quantum-confined Stark effect (QCSE)6, since they are grown on non-polar moriented sidewalls. As already mentioned in literature, there are several advantages of core-shell rod LEDs over conventional planar LEDs7,8. In order to exploit these interesting advantages, the 3D geometry does not necessarily need to be rod-like, but could also be in a so-called fin shape, including a few distinct advantages in comparison to microrod structures. These fin structures are long, thin and high GaN walls with non-polar sidewalls and aspect ratios (height to width as well as length to height) much larger than one. The growth of III-nitrides in fine wall-shaped structures, mainly by molecular beam epitaxy (MBE), was already shown by Kishino and Kikuchi9. MOVPE growth of these fin structures was demonstrated by T.-W. Yeh et al.10 and by A. K. Rishinaramangalam et al11. Due to the small footprint of fins and due to defect annihilation at the sidewall surfaces, lower defect densities can be expected as compared to planar GaN layers. In addition, core-shell fin LEDs have, under certain circumstances, an even larger active area ratio (AAR), i.e. active area (equivalent to surface area) to substrate area in comparison with core-shell rod LEDs: For hexagonally shaped rod LEDs in a hexagonal pattern AAAAAArrrrrr = 6 √3 HH∗DD PP2 with considering the height H, diameter D (defined as two times the circumradius of the hexagonal rod) and pitch P (defined as distance between the centers of neighboring structures) of the columns, respectively. If the end facets of the fins are neglected, for fin LEDs it is AAAAAAffffff = 2HH PP with the height H and pitch P of the fins, respectively. Taking the same diameter D (for rods) or width W (for fins) and https://doi.org/10.24355/dbbs.084-201912181044-0 4 the same height and pitch for rods and fins, there is an enhancement in the AAR of AAAAAAFFFFFF AAAAAArrrrrrrr = PP √3DD . For a pitch of more than 1.7 times the diameter or width, the AAR for fins is larger than that for rods. This prerequisite is fulfilled in most core-shell rod LED designs, since the outer shell layers, e.g. the p-GaN, need additional space in between the structures. Furthermore, the structures should have enough distance between each other to couple out light with high efficiency. If micro-grained optical converter materials filled into the 3D-ensemble are used for white light applications, even more space is required between the rods or fins. Besides the greater AAR of fins, the vertical current density in the fin LED core is less than in a rod core, assuming comparable active area and driving conditions. This is due to a larger footprint area per active area for fins than for rods. Thus, the current density in the base area is reduced and less problems regarding heating can be expected in fin LEDs. For rod LEDs the footprint ratio FFAArrrrrr = √3DD 8HH , while for fin LEDs it holds FFAAffffff = WW 2HH . Taking again the same diameter or width and the same height for rods and fins, there is an enhancement of FFAAffFFFF FFAArrrrrr = 4 √3 ≈ 2.31. Another advantage of GaN fins is their much easier fabrication: Less effort is needed for lithography masks since a precise pattern profile is necessary in one dimension only, which is less critical for nanoimprint lithography and allowing laser interference methods to be used. Also, the analysis of single fin LEDs is much easier. E.g. by cleaving the samples perpendicular to the fin longitudinal direction, a cross-sectional view into the structures can easily be achieved, which is extremely difficult for rod geometries. Also, GaN fins have higher mechanical stability than rods and therefore are less sensitive to further processing steps. Unlike GaN fins, rod structures offer six large edge lines between the sidewall facets. Therefore, boundary effects, like e.g. an increased indium content at the edges between two non-polar planes due to different strain relaxation12,13 https://doi.org/10.24355/dbbs.084-201912181044-0 5 could become an issue. In this respect, fins can be expected to be much more homogeneous. For the same reason, the current conducting path inside the n-GaN core could be more uniformly for GaN fins10. Last but not least, the fins provide relatively large non-polar surfaces, each of several thousand μm2, at a low cost. These surfaces could be viewed as “vertical a-plane GaN pseudo substrate” with low defect density, which can be used to study the properties of non-polar GaN without the necessity to use very expensive a-oriented GaN substrates. Such fins could be applied for LEDs10,11, but also for laser structures, Fin-FETs or HEMTs, waveguides14 and much more. GaN fins, also called nanowalls or nanosheets in other publications, with {1-100} non-polar sidewall planes and aspect ratios of two or more have already been fabricated by pulsed growth mode selective area in MOVPE10,11. In this article, we demonstrate the growth of GaN fins with {11-20} non-polar sidewalls by continuous growth mode selective area MOVPE. The growth rates are enhanced compared to pulsed growth mode and thus large vertical dimensions of the fins are shown. Aspect ratios of almost 14 could be achieved, the highest ever reported for bottom-up GaN fin geometries. The dependencies on pattern orientation, pattern geometry and growth conditions are described. EXPERIMENTAL SECTION The fin structures were grown by SAG on 2” wafer templates of two different kinds, either SiOx on GaN on sapphire or SiOx directly on sapphire. The 30 nm thick SiOx masking layer was structured by photolithography. Either a lift-off process with an image reversal lithography step and SiOx evaporation or a positive lithography step with subsequent dry etching of the SiOx (by inductively coupled plasma, using SF6) is applied. The photolithography is done with a 300 nm thick layer of AZ 5214E. Both techniques resulted in very comparable finlike structures. The lithography mask consists of different patterns of line openings with lengths of 10 μm, 25 μm, 50 μm, 100 μm, 250 μm, 500 μm and 1000 μm, with pattern widths (Wp) of 0.5 https://doi.org/10.24355/dbbs.084-201912181044-0 6 μm, 1 μm, 1.5 μm and 2 μm and pitches of three, six and nine times the width (see Figure 1). These patterns are repeatedly rotated by 15° relative to each other, arranged in a circle with six patterns of lines parallel to the a-direction (resulting in fins with m-plane sidewalls), six patterns of lines parallel to the m-direction (resulting in fins with a-plane sidewalls) and additional twelve patterns oriented in directions in between these two. Besides of this main circle of patterns, at the rim of the photolithography mask are structures with even longer line openings and with smaller rotation angles relative to mand a-direction. The orientation of the lines is given as the angle to the sapphire wafer flat, taking into account the 30° twist of GaN gr

A methodology based on the use of Electron Beam Lithography for contacting individual nanowires on top of non-flat micromembranes and microhotplates has been implemented, and the practical details have been exhaustively described. The different fabrication steps have been adapted to the substrate's topology, requiring specific holders and conditions. The methodology is demonstrated on individual SnO2 nanowires, which, after fabrication, have been characterized as functional resistive gas nanosensors towards NH3 and benchmarked against similar devices fabricated using more conventional Dual Beam Focused Ion Beam techniques, demonstrating the superior properties of the here presented methodology, which can be further extended to other non-conventional suspended substrates and nanomaterials.

Pulsed sputter deposition has been demonstrated to be a viable process for the growth of high quality GaN and InGaN/GaN LEDs. It enables the fabrication of nitride LEDs with a red emission wavelength at large areas. In this study, we explore details on the epitaxial sputter deposition of GaN with a particular emphasis on ion damage. By changing the argon to nitrogen ratio, we adjust the growth mode from island to layer growth. TEM revealed speckles in the epitaxial GaN, which could be identified as isolated basal stacking faults, acting as non-radiative recombination centers. Using Monte Carlo methods, we modeled the energies of backscattered and sputtered atoms in order to get information on the ion damage mechanisms. Considering the collisions on the way from the target to the substrate, we found energetic nitrogen to induce the speckles. A shielding mechanism based on metallic gallium has been identified, leading to the strongly increased luminescence quality in comparison to the non-shielded material.

GaN fins on GaN‐on‐sapphire templates are fabricated by continuous mode selective area metalorganic vapor phase epitaxy. The fins exhibit high aspect ratios and smooth nonpolar a‐plane sidewalls with an ultra‐low threading dislocation density of a few 105 cm−2 making them ideally suited for optoelectronic to electronic applications. A detailed analysis of the inner structure of GaN fins is provided by the help of marker layer experiments and correlation of results from fins fabricated under different growth conditions, leading to the development of a growth model to explain the final geometry and optical as well as electrical properties of these high aspect ratio fins. Distinctly different material properties for the central and outer parts of the fins are detected. Whereas the outer sidewalls represent high quality GaN surfaces with very low defect densities, a strong quenching of near band edge emission (NBE) in the central part of the fins is accompanied by heavy compensation of free electrons. A possible explanation is the incorporation of excessive point defects, like intrinsic defects or carbon impurity. The sidewall regions, however, prove to be highly suitable for device applications due to their strong NBE emission, low dislocation density, and high free carrier concentration.

GaN fins are 3D architectures elongated in one direction parallel to the substrate surface. They have the geometry of walls with a large height to width ratio as well as small footprints. When appropriate symmetry directions of the GaN buffer are used, the sidewalls are formed by non-polar {1 1 −2 0} planes, making the fins particularly suitable for many device applications like LEDs, FETs, lasers, sensors or waveguides. The influence of growth parameters like temperature, pressure, V/III ratio and total precursor flow on the fin structures is analyzed. Based on these results, a 2-temperature-step-growth was developed, leading to fins with smooth side and top facets, fast vertical growth rates and good homogeneity along their length as well as over different mask patterns. For the core–shell growth of fin LED heterostructures, the 2-temperature-step-growth shows much smoother sidewalls and less crystal defects in the InGaN QW and p-GaN shell compared to structures with cores grown in just one step. Electroluminescence spectra of the 2-temperature-step-grown fin LED are demonstrated.

3D GaN structures attract a lot of attention since they are expected to open up new routes to solid state-based high power light engines. In this paper we present different technologies employed by the Institute of Semiconductor Technology at TU Braunschweig to manufacture 3D GaN structures with a core-shell geometry or an axially embedded light emitting structure. Especially the core-shell design offers a dramatically enhanced active area per chip, since the active area is scaling with the height of the 3D structures. New metrological approaches to analyze these nanostructures are necessary, as conventional "planar" techniques cannot be applied. By combining high resolution scanning electron microscopy with electrical and optical measurements we could achieve insight into these structures. Besides the optical characterization of ensembles and single structures we also present a way to model the paths of light emitted by single microLEDs inside an ordered pattern of LED structures.

Three-dimensional GaN micro- and nanorods with a high aspect ratio have recently gained substantial interest in light-emitting diode research, due to their reduced defect density, their nonpolar sidewalls, and their increased active area. Here, we present an alternative geometry for high aspect ratio three-dimensional nanostructures: vertically standing GaN "walls", so-called GaN fins. With high aspect ratios, these GaN fins exhibit the same interesting characteristics as their rod counterparts mentioned above. Beyond that, because of their geometry, the respective material analysis and device processing can be expected to be less complex. We are able to demonstrate the highly reproducible selective area growth of these fins by continuous mode metalorganic vapor phase epitaxy. Fin heights of more than 50 mu m (aspect ratios of nearly 14) could be achieved, and growth rates are as high as 22.8 mu m/h in the beginning of the growth. The sidewalls are smooth nonpolar <11<(2)over bar>0> a-planes, suitable for optoelectronic devices due to the missing quantum-confined Stark effect and less edge effects compared to rods. We investigate the influence of pattern orientation and geometry on the fin morphology. Moreover, the influence of silane flow, which is known to enhance the vertical growth rate, and other growth parameters are systematically explored.

Summary form only given. GaN nanorods and related high aspect ratio 3D GaN nanostructures recently attracted a lot of attention since they are expected to be an exciting new route towards extending the freedom for device design in GaN technology. Such structures offer large surfaces, defect free high quality material, as well as non-polar surface orientations, including the possibility to use very large area foreign substrates without implementing large area strain. All of these aspects are difficult or impossible to achieve when planar substrate approaches are used. Meanwhile, such 3D high aspect ratio GaN based nanostructures can reproducibly be fabricated with high aspect ratios and good homogeneity, and more and more device and application aspects are under investigation.Details on the MOCVD growth of such high aspect ratio structures will be given, and the influence of growth parameters (and particularly the silicon doping) on the properties of the quantum wells will be discussed. Silicon is shown to lead to passivation effects at m-plane sidewall surfaces, which hinder the high quality growth of InGaN quantum wells. Strategies to circumvent this problem will be discussed, leading to InGaN quantum wells with PL-IQE values of 60% at room temperature. This talk will give an overview on the state of the art of our 3D GaN research, pointing out the necessity for further epitaxy related research, but also describing the increasingly interesting demonstration of 3D devices and their substantial potential for solid state lighting.

The fabrication and use of silicon nanowire (SiNW) array-patterned microcantilever sensors for enhancing aerosol mass detection are described. Surface modification of the cantilever is performed selectively by combining the processes of nanoimprint lithography, photolithography and inductively coupled plasma cryogenic reactive ion etching. Cylindrical wire structures of 300 nm diameter with aspect ratios of 3-7 can be realised for the current SiNWs, which can be altered depending on the nanoimprint stamp size and etching recipe. Owing to the rise in the collection surface area of the sensor provided by vertical SiNWs, an increase of aerosol sampling efficiency can be obtained during cigarette smoke exposure, which is a factor of 1.5 higher than that of a corresponding plain cantilever. This proposed structure is intended to be used as a sensor module of a personal aerosol mass detector.

In this paper, silicon nanowire (SiNW) array-patterned microcantilever sensors excited in the in-plane resonance mode have been designed, fabricated, characterized, and used for enhanced detection of atmospheric aerosols (i.e., cigarette smoke and carbon black aerosols). The selective surface modification of the cantilever is mainly performed by a combination of nanoimprint lithography (NIL), photolithography, and inductively coupled plasma (ICP) cryogenic dry etching. Diameter and aspect ratio of the vertical SiNWs can be adjusted depending on the nanoimprint stamp and etching performance, with the currently realized cylindrical structure diameter of 300 nm and varied aspect ratios of 3 - 7. In resonance characterization, the fabricated sensors exhibit high measured quality factors (Q-factors) of 7000 +- 1300 during in-plane mode operation in air. The aerosol sampling efficiency can be increased by a factor of 1.5 higher than that of a corresponding plain cantilever in a cigarette smoke exposure experiment because of the rise in collection surface area of the sensor given by the SiNWs. Moreover, the calibrated mass concentration of carbon black nanoparticles (CBNPs) monitored by the SiNW-patterned cantilever is found to be close to that measured by a standard aerosol NP monitoring instrument (fast mobility particle sizer: FMPS, TSI 3091, TSI Inc.).

This paper presents the design, fabrication, and use of silicon nanowire (SiNW) arrays-patterned microcantilever sensors excited in the in-plane resonance mode to enhance the detection of airborne particulate matter (PM). Electrothermal excitation elements of p-diffused heating resistors were introduced in the current sensor system to replace the formerly used external piezoceramic stack actuator. The sensors exhibited high measured quality factors (Q-factors) of 4702 ± 102 during their in-plane mode operations in air, which are four times larger than those of the fundamental out-of-plane mode. To selectively define arrays of vertical SiNWs on the surface of the micromechanical cantilever, nanoimprint lithography (NIL) is combined with conventional photolithography. The diameter and position of the SiNWs can be adjusted depending on the nanoimprint stamp with the smallest cylindrical pattern possible down to 50 nm in diameter. By modifying the resonator surface, the PM sampling efficiency can be improved by a factor of 1.5 greater than that of a corresponding plain cantilever in a cigarette smoke exposure experiment because of the rise in collection surface area of the sensor given by the SiNWs.

Silicon resonant sensors with large surface area-to-volume ratios provide high weighing sensitivity. This fact implies the possibility for detection of slight mass changes [i.e. by attached nanoparticles (NPs)]. Vertical silicon nanowire (SiNW) resonators are therefore suitable for exposure assessment or airborne NPs. SiNW arrays are top-down fabricated by nanolithography and subsequent inductively coupled plasma reactive ion etching at cryogenic temperature. Nanolithography is performed by conventional UV-lithography and nanoimprint for even smaller structures. Wire diameters are further reduced by multiple thermal oxidations and oxide stripping at times. Parameter effects of cryogenic dry etching are studied for SiNW arrays.

The invention relates to a method for producing a surface-structured article by means of an imprint lithography method, are removed in the after the imprint step of imprint lithography method of the surface of the produced surface-structured article to be removed Extrahenten means of mechanical machining of this object. The invention further relates to the use of at least one side adhesive film.