As the efficiency potential for the industrial P-type Al-BSF silicon solar cell reaches its limit, new solar cell technologies are required to continue the pursuit of higher efficiency solar power at lower cost. It has been demonstrated in literature that among possible alternative solar cell structures, cells featuring a local BSF (LBSF) have demonstrated some of the highest efficiencies seen to date. Implementation of this technology in industry, however, has been limited due to the cost involved in implementing the photolithography procedures required. Recent advances in solar cell doping techniques, however, have identified ion implantation as a possible means of performing the patterned doping required without the need for photolithography. In addition, past studies have examined the potential for building solar cells on N-type silicon substrates, as opposed to P-type. Among other advantages, it is possible to create N-type solar cells which do not suffer from the efficiency degradation under light exposure that boron-doped P-type solar cells are subject to. Industry has not been able to capitalize on this potential for improved solar cell efficiency, in part because the fabrication of an N-type solar cell requires additional masking and doping steps compared to the P-type solar cell process. Again, however, recent advances in ion implantation for solar cells have demonstrated the possibility for bypassing these process limitations, fabricating high efficiency N-type cells without any masking steps. It is clear that there is potential for ion implantation to revolutionize solar cell manufacturing, but it is uncertain what absolute efficiency gains may be achieved by moving to such a process. In addition to development of a solar specific ion implant process, a number of new thermal processes must be developed as well. With so many parameters to optimize, it is highly beneficial to have an advanced simulation model which can describe the ion implant, thermal processes, and cell performance accurately. Toward this goal, the current study develops a process and device simulation model in the Sentaurus TCAD framework, and calibrates this model to experimentally measured cells. The study focuses on three main tasks in this regard: Task I - Implant and Anneal Model Development and Validation This study examines the literature in solar and microelectronics research to identify features of ion implant and anneal processes which are pertinent to solar cell processing. It is found that the Monte Carlo ion implant models used in IC fabrication optimization are applicable to solar cell manufacture, with adjustments made to accommodate for the fact that solar cell wafers are often pyramidally textured instead of polished. For modeling the thermal anneal processes required after ion implant, it is found that the boron and phosphorus cases need to be treated separately, with their own diffusion models. In particular, boron anneal simulation requires accurate treatment of boron-interstitial clusters (BICs), transient enhanced diffusion, and dose loss. Phosphorus anneal simulation requires treatment of vacancy and interstitial mediated diffusion, as well as dose loss and segregation. The required models are implemented in the Sentaurus AdvancedModels package, which is used in this study. The simulation is compared to both results presented in literature and physical measurements obtained on wafers implanted at the UCEP. It is found that good experimental agreement may be obtained for sheet resistance simulations of implanted wafers, as well as simulations of boron doping profile shape. The doping profiles of phosphorus as measured by the ECV method, however, contain inconsistencies with measured sheet resistance values which are not explained by the model. Task II - Device Simulation Development and Calibration This study also develops a 3D model for simulation of an N-type LBSF solar cell structure. The 3D structure is parametrized in terms of LBSF dot width and pitch, and an algorithm is used to generate an LBSF structure mesh with this parametrization. Doping profiles generated by simulations in Task I are integrated into the solar cell structure. Boundary conditions and free electrical parameters are calibrated using data from similar solar cells fabricated at the UCEP, as well as data from lifetime test wafers. This simulation uses electrical models recommended in literature for solar cell simulation. It is demonstrated that the 3D solar cell model developed for this study accurately reproduces the performance of an implanted N-type full BSF solar cell, and all parameters fall within ranges expected from theoretical calculations. The model is then used to explore the parameter space for implanted N-type local BSF solar cells, and to determine conditions for optimal solar cell performance. It is found that adding an LBSF to the otherwise unchanged baseline N-type cell structure can produce almost 1% absolute efficiency gain. An optimum LBSF dot pitch of 450um at a dot size of 100um was identified through simulation. The model also reveals that an LBSF structure can reduce the fill factor of the solar cell, but this effect can be offset by a gain in Voc. Further efficiency improvements may be realized by implementing a doping-dependent SRV model and by optimizing the implant dose and thermal anneal. Task III - Development of a Procedure for Ion Implanted N-type LBSF Cell Fabrication Finally, this study explores a method for fabrication of ion-implanted N-type LBSF solar cells which makes use of photolithographically defined nitride masks to perform local phosphorus implantation. The process utilizes implant, anneal, and metallization steps previously developed at the UCEP, as well as new implant masking steps developed in the course of this study. Although an LBSF solar cell has not been completely fabricated, the remaining steps of the process are successfully tested on implanted N-type full BSF solar cells, with efficiencies reaching 20.0%.

A new type of photolithography, Pattern-Integrated Interference Lithography (PIIL), was demonstrated. PIIL is the first-ever integration of pattern imaging with interference lithography in a single-exposure step. The result is an optical-intensity distribution composed of a subwavelength periodic lattice with integrated functional circuit elements. To demonstrate the PIIL method, a Pattern-Integrated Interference Exposure System (PIIES) was developed that incorporates a projection imaging capability in a novel three-beam interference configuration. The purpose of this system was to fabricate, in a single-exposure step, representative photonic-crystal structures. Initial experimental results have confirmed the PIIL concept, demonstrating the potential application of PIIL in nano-electronics, photonic crystals, biomedical structures, optical trapping, metamaterials, and in numerous subwavelength structures. In the design of the PIIES configuration, accurate motif geometry models were developed for the 2D plane-group symmetries possible via linearly-polarized three-beam interference, optimized for maximum absolute contrast and primitive-lattice-vector direction equal contrast. Next, a straightforward methodology was presented to facilitate a thorough analysis of effects of parametric constraints on interference-pattern symmetries, motif geometries, and their absolute contrasts. With this information, the design of the basic PIIES configuration was presented along with a model that simulates the resulting optical-intensity distribution at the system sample plane. Appropriate performance metrics were defined in order to quantify the characteristics of the resulting photonic-crystal structure.

Diese Arbeit beschäftigt sich mit der Synthese neuer photoreaktiver Polymere, die bei Bestrahlung mit Licht (Hg-Dampflampe, fs-gepulster Ti:Sa-Laser) definierte Reaktionen durchlaufen. Mittels kontrolliert-radikalischer Polymerisation und anschließender polymeranaloger Reaktion wurden verschiedene Azobenzen-Derivate, Arylazosulfonat-Derivate und photolabil geschützte Aminogruppen (Nitroveratryloxycarbonyl, Nvoc) in Methacrylat-Polymere eingeführt. Diese Strukturen wurden ausführlich hinsichtlich ihrer Struktur und vor allem ihrer photochemischen Eigenschaften (Extinktionskoeffizienten, Zerfallskinetik) untersucht. Dünne Schichten (d<30nm) der so hergestellten Materialien wurden bei der Entwicklung einer neuen photolithographischen Methode, der plasmonischen Nanolithographie, eingesetzt.

This work focusses on the advances of organic light-emitting diodes (OLEDs) for large area display and solid-state-lighting applications. OLED technology has matured over the past two decades, aided by the rapid advances in development of the novel material and device concepts. State-of-the-art OLEDs reach internal efficiencies of 100% and device lifetimes acceptable for commercial display applications. However, further improvements in the blue emitter stability and the device performance at the high brightness are essential for OLED technology to secure its place in the lighting market. As the current passing through the device increases, a rapid decrease in OLED efficiency, so-called efficiency roll-off, takes place, which hinders the use of OLEDs wherever high brightness is required. In addition, white OLEDs comprising multiple emitter molecules suffer from the emission colour change as the operating conditions are varied or as the devices age. Despite side-by-side structuring of the monochrome OLEDs could in principle circumvent most of bespoke issues, the limitations imposed by the shadow mask technique, employed to structure vacuum deposited films, renders such approach impractical for fabrication of the devices on a large scale. In order to address these issues, photolithographic patterning of OLEDs is implemented. Highly efficient state-of-the-art devices are successfully structured down to tens of micrometers with the aid of orthogonal lithographic processing. The latter is shown to be a promising alternative for the shadow mask method in order to fabricate the full-colour RGB displays and solid-state-lighting panels. Photo-patterned devices exhibit a virtually identical performance to their shadow mask counterparts on a large scale. The high performance is replicated in the microscale OLEDs by a careful selection of functional layer sequence based on the investigation of the morphological stability and solubility of vacuum deposited films. Microstructured OLEDs, fabricated in several different configurations, are investigated and compared to their large area counterparts in order to account for the observed differences in charge transport, heat management and exciton recombination in bespoke devices. The role of the Joule heat leading to the quenching of the emissive exciton states in working devices is discussed. Structuring the active OLED area down to 20 micrometer is shown to improve the thermal dissipation in such devices, thus enabling the suppression of the efficiency roll-off at high brightness in white-emitting electroluminescent devices based on side-by-side patterned OLEDs. / Die vorliegende Arbeit beschäftigt sich mit den neusten Errungenschaften von organischen Licht-emittierenden Dioden (OLEDs) für großflächige Beleuchtungs- und Displayanwendungen. Die OLED-Technologie hat sich in den letzten zwei Jahrzehnten, begünstigt von neuartigen Material- und Bauteilkonzepten, weit entwickelt. Im aktuellen Stand der Technik erreichen OLEDs sowohl interne Effizienzen von 100% als auch Lebensdauern die für die kommerzielle Nutzung in Displays ausreichend sind. Nichtsdestotrotz sind weitere Verbesserungen für die Stabilität blauer Emitter und die Leistungsfähigkeit bei hohen Leuchtstärken erforderlich, damit die OLED Technologie ihren Platz auf dem Markt behaupten kann. Mit steigender Stromstärke, die durch ein solches Bauteil fließt, sinkt die Effizienz rapide (der sogenannte Effizienz-Roll-Off), was die Nutzung von OLEDs verhindert, wann immer hohe Leuchtstärken erforderlich sind. Zusätzlich verändern weiße OLEDs ihre Farbkomposition durch die unterschiedliche Alterung der unterschiedlichen Emittermoleküle oder veränderte Einsatzbedingungen. Obwohl die laterale Strukturierung nebeneinander aufgebrachter, monochromer OLEDs diese Probleme umgehen könnte, ist diese Herangehensweise durch die aktuelle Schattenmasken-Technologie limitiert, welche zur Strukturierung vakuumprozessierter Dünnschichten eingesetzt wird, und somit unpraktikabel für die Massenproduktion. Um diese Problemstellungen zu umgehen, wird hier die photolithographische Strukturierung von OLEDs angewendet. Mithilfe der orthogonalen Lithographie können hocheffiziente Bauteile damit erfolgreich auf Größenordnungen von 10 Mikrometer strukturiert werden. Dies zeigt, dass die orthogonale Prozessierung eine vielversprechende Alternative für die Schattenmasken-Technologie darstellt und für die Herstellung von RGB-Displays und Beleuchtungspanelen geeignet ist. Photostrukturierte Bauteile zeigen dabei eine nahezu identische Leistungsfähigkeit zu solchen, die großffächig mittels Schattenmasken hergestellt wurden. Diese hohe Leistungsfähigkeit kann hierbei durch eine sorgfältige Auswahl der einzelnen funktionellen Schichten erreicht werden, welche auf Untersuchung von morphologischer Stabilität und Löslichkeit dieser Schichten basiert. Mikrostrukturierte OLEDs in verschiedenen Konfigurationen werden mit ihren großflächigen Gegenstücken verglichen, um beobachtete Abweichungen im Ladungstransport, der Wärmeverteilung, sowie der Exzitonenrekombination zu erklären. Die Rolle der Joule'schen Wärme, die zur Auslöschung der emittierenden Exzitonenzustände führt, wird hier diskutiert. Die thermische Dissipation kann dabei verbessert werden, indem die aktive Fläche der OLED auf 20 Mikrometer herunterstrukturiert wird. Folglich kann der Effizienz-Roll-Off bei hohen Leuchtstärken in lateral strukturierten weißen elektrolumineszenten Bauteilen unterdrückt werden.

Transparent electrodes (TEs) have become important components of displays, touch screens, and solar photovoltaic (PV) energy conversion devices. As electrodes, they must be electrically conductive while being transparent. Transparent materials are normally poor conductors and materials with high electrical conductivity, such as metals, are typically not transparent. From the few candidate materials, indium tin oxide (ITO) is currently the best available, but indium is an expensive material and ITO cost has risen with increasing demand. Therefore, alternative materials or methods are sought to encourage production needs of applications and help in reducing their price. This thesis presents and discusses results of experimental work for a method, field-directed chaining, to produce a TE device which is nanowire-based, with a figure of merit FoM= 2.39 x10E-4 Ohm E-1, comparable to ITO but with potential for far lower cost. Using electric field-directed chaining, multiple parallel long chains of metal nanowires are assembled on inexpensive transparent materials such as glass by field directed nanowire chaining, using methods first demonstrated in our laboratory. In this work, we have improved the fraction of functional chains, by tuning the field/voltage, a key step in increasing the FoM and lowering the cost. The effect of operating parameters on TE optical and electrical properties has been studied and identified as well. From experiments with twenty seven substrates, each with a range of electric field and nanowire concentration, the highest light transmission achieved is 78% and the lowest sheet resistance achieved is 100 Ohm/sq. Among all the operating parameters, the electric field has the most significant influence on the fraction of nanowire chains that are functional. In the operating range of electric field strength available to us, we observed a monotonic increase in the fraction of functional nanowire chains. We found a counter-intuitive change in TE properties in a sub-range of nanowire concentration, associated with a change in the structure of chained patterns. / Graduate

ASICs estruturados com leiautes regulares representam uma das soluções para a perda de rendimento de fabricação de circuitos integrados em tecnologias nanométricas causada pela distorção de fotolitografia. Um método de projeto de circuitos integrados ainda mais restritivo resulta em ASICs estruturados configuráveis apenas pelas camadas de vias, que são compostos pela repetição do mesmo modelo de bloco em todas as camadas do leiaute, exceto as camadas de vias. A escolha do modelo de bloco tem grande influência nas características do circuito final, criando a demanda por novas ferramentas de CAD que possam avaliar e comparar tais modelos em seus diversos aspectos. Esta tese descreve um ambiente de CAD baseado em SAT, capaz de avaliar o aspecto de capacidade lógica em padrões de blocos configuráveis por vias. O ambiente proposto é genérico, podendo tratar quaisquer padrões de bloco definido pelo usuário, e se comporta de maneira eficiente quando aplicado aos principais padrões já publicados na literatura. / Structured ASICs with regular layouts comprise a design-based solution for IC manufacturing yield loss in nanometer technologies caused by photolithography distortions. Via-configurable structured ASICs is even a more restrictive digital IC design method, based on the repetition of a block template comprising all layout layers except the vias one. The choice of such a design strategy impacts greatly the final circuit characteristics, arising the need for specific CAD tools to allow template evaluation and comparison in different aspects. This work presents a SAT-based CAD environment for evaluating the logical capacity aspect of via-configurable block templates. The proposed environment is able to support any user-defined template, and behaves efficiently when applied to block templates presented in related literature.

Orientador: Prof. Dr. Marcos Roberto da Rocha Gesualdi / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2017. / Estudos da aplicação de moduladores espaciais de luz do tipo LCoS (Liquid Cristal on Silicon) e técnicas holográficas em substituição às máscaras no processo de fotolitografia são apresentados. Hologramas Gerados por Computador (HGC) a partir de duas imagens com dimensões conhecidas, simulando uma máscara de campo claro e uma máscara de campo escuro, foram aplicados a um modulador espacial de luz LCoS conectado a um arranjo óptico capaz de reduzir as imagens reconstruídas, permitindo o levantamento dos parâmetros de maior relevância no processo de fotolitografia para fabricação de estruturas micrométricas e, a partir da sua caracterização, identificar os limites impostos pelo modulador espacial de luz LCoS nesse processo. Registro das imagens, com diferentes dimensões, adquiridas à partir da reconstrução dos HGC provenientes das máscaras de campo claro e campo escuro, foram realizados através de uma câmera CCD e filmes de alta resolução. Os resultados permitiram a visualização e medição de estruturas com até 13 Pm e representam uma base de estudo na busca de alternativas para substituição das máscaras em processos de fotolitografia / Application studies of the Spatial Light Modulators LCoS type (Liquid Crystal on Silicon) and holographic techniques to replace the masks in the photolithography process are presented. Computer-generated Holograms (HGC) from two images with known dimensions, simulating a clear field mask and a dark field mask, were applied to a Spatial Light Modulators LCoS connected to an optical arrangement capable of reducing the reconstructed images, allowing the survey of the parameters of greater relevance in the process of photolithography to fabricate micrometric structures and from its characterization to identify the limits imposed by the Spatial Light Modulators LCoS in this process. Recording of the images, with different dimensions, acquired from the reconstruction of the HGC from clear field and dark field masks, were performed through a CCD camera and high resolution films. The results allowed the visualization and measurement of structures up to 13 ìm and represent a base of study in the search of alternatives for replacing the masks in photolithography processes.

ASICs estruturados com leiautes regulares representam uma das soluções para a perda de rendimento de fabricação de circuitos integrados em tecnologias nanométricas causada pela distorção de fotolitografia. Um método de projeto de circuitos integrados ainda mais restritivo resulta em ASICs estruturados configuráveis apenas pelas camadas de vias, que são compostos pela repetição do mesmo modelo de bloco em todas as camadas do leiaute, exceto as camadas de vias. A escolha do modelo de bloco tem grande influência nas características do circuito final, criando a demanda por novas ferramentas de CAD que possam avaliar e comparar tais modelos em seus diversos aspectos. Esta tese descreve um ambiente de CAD baseado em SAT, capaz de avaliar o aspecto de capacidade lógica em padrões de blocos configuráveis por vias. O ambiente proposto é genérico, podendo tratar quaisquer padrões de bloco definido pelo usuário, e se comporta de maneira eficiente quando aplicado aos principais padrões já publicados na literatura. / Structured ASICs with regular layouts comprise a design-based solution for IC manufacturing yield loss in nanometer technologies caused by photolithography distortions. Via-configurable structured ASICs is even a more restrictive digital IC design method, based on the repetition of a block template comprising all layout layers except the vias one. The choice of such a design strategy impacts greatly the final circuit characteristics, arising the need for specific CAD tools to allow template evaluation and comparison in different aspects. This work presents a SAT-based CAD environment for evaluating the logical capacity aspect of via-configurable block templates. The proposed environment is able to support any user-defined template, and behaves efficiently when applied to block templates presented in related literature.

Dans cette thèse, nous développons des micro-concentrateurs de lumière en vue d’applications dans l’infrarouge. Les optiques, plates, de dimensions comparables à la longueur d’onde, sont formées d’une couche micronique de métamatériau, constituée de polymère structuré par des trous d’air. Une focalisation dans la zone de Fresnel des structures est recherchée en réalisant un gradient d’indice, obtenu en variant le diamètre des inclusions d’air (de λ//20 à λ/8). Des simulations électromagnétiques sont d’abord effectuées pour valider un design. La fabrication de ces concentrateurs repose sur la structuration d’une couche de photorésine à l’aide d’une technique de lithographie optique 3D à deux photons. Les mesures obtenues par l’imagerie infrarouge des structures montrent l’obtention d’une focalisation en accord avec les simulations pour un volume de concentrateur de 1,5 λ³, en dépit de l’absorption résiduelle de la résine choisie. Les structures proposées sont invariantes dans la direction axiale et peu épaisses, et peuvent donc être transférées dans d’autres types de matériaux ayant des indices de réfraction plus importants, comme le silicium. Les structures proposées peuvent également servir de plateforme pour réaliser un confinement sub-longueur d’onde par l’ajout d’antennes plasmoniques / In this thesis, we develop flat light concentrators for infrared applications. The structures have dimensions comparable with the wavelength and are made of a metamaterial layer (few microns) made of polymer with air holes inclusions. Light focusing in the Fresnel zone of the structures is achieved by a gradient index profile obained by chirping the holes diameter (from λ//20 to λ/8). Electromagnetic simulations are first performed to validate a design. The fabrication of these concentrators is then made by direct laser writing using a 3D two-photon lithography technique. Infrared imaging of the structures reveals a clear focusing of the infrared light for concentrators volume as small as 1,5 λ³, in agreement with the electromagnetic simulations. Considering that the metamaterial concentrator slabs are invariant in the axial direction and not too thick, similar structures can be transferred in transparent substrates such as silicon using deep reactive ion etching. A subwavelength light confinement can also be exploited by adding plasmonic antenna on the top surface of the flat concentrators

Le contexte du réchauffement climatique entraîne un développement des technologies CSP (Concentrated Solar Power). La réduction des coûts de production de ces technologies passe par une amélioration de la durabilité et de l'efficacité des composants des centrales solaires. Les températures de fonctionnement élevées du CSP (250-600°C) nécessitent d'employer des absorbeurs spectralement sélectifs afin de limiter les pertes par radiation. Cette thèse propose une architecture originale d'absorbeurs sélectifs stables à haute température sous air en combinant un dépôt de TiAlN en couches minces avec un réseau de diffraction. L'ajout d'une texturation de surface augmente l'absorption solaire du dépôt par un effet d'absorption et de gradient des indices optiques effectifs conduisant à une augmentation du rendement photothermique de l'absorbeur. Dans ce mémoire, la modélisation du comportement optique des absorbeurs texturés, les méthodes de fabrication du réseau de diffraction ainsi que le dépôt des couches minces par PVD et PECVD seront abordés et les mesures expérimentales seront comparées aux modélisations. L'analyse des absorbeurs texturés fabriqués confirme un gain de rendement photothermique pouvant atteindre +3% ainsi qu'une stabilité thermique remarquable à 500°C sous air jusqu'à 300 h de recuit / The global warming context reinforces the development of CSP technologies. Cost reduction of CSP requires the improvement of component durability and efficiency. The solar absorbers should be spectrally selective since the high working temperatures of CSP plants increase the radiative thermal losses. This thesis proposes an original, spectrally selective absorber structure combining TiAlN based coatings and diffractive gratings. The surface texturing provided by the diffractive gratings improves the solar absorption of the thin coating by an effective optical index gradation effect leading toincreased photothermal efficiency. In this thesis, the modeling of the textured absorber’s optical behavior, fabrication methods of diffractive gratings, as well as layer deposition by PVD/PECVD will be discussed. Experimental measurements will be compared to the theoretical modelling. The experimental analysis of textured absorbers confirms the increase of photothermal efficiency by almost 3%, as well as a good thermal stability at 500°C in air for 300 hours of annealing