In the trends of high clock rate, lower voltage, small volume, and portable requirement for present electric products, the noise immunity of high speed digital circuit becomes a critical factor for system designer. ESD problem becomes more and more important for electric products because of the triboelectricity caused by human body and synthetic material. It¡¦s an important issue for designer to understand the ESD phenomena in grounding and floating system accurately. In this thesis, a reliable setup for the ESD measurement is proposed both in grounding and floating systems. ESD behavior and protection devices are studied in detail and a corresponding SPICE model is built up for simulation validation.

The trends of present design in electronic systems are towards high speed, small size, and lower voltage levels. The noise immunity of high speed digital circuit decreases. ESD problem becomes more and more important for electric products because of the triboelectricity caused by human body with synthetic material. In this thesis we introduce the phenomenon in real life ESD caused by a charged human body source. Then we provide a good measurement method of ESD which enhances the repetition that gives a reliable and accurate result. Finally we try to build the numerical model for the air and contact discharge simulation by FDTD to provide a good measurement validation.

<p>This thesis deals with the reliability and life-time ofelectronic components and ways to determine these factors.Plastic encapsulated and open test circuits were assessed atdifferent humidity and temperature conditions. From the resultsan acceleration factor could be derived using the Arrheniusrelation. This factor is used to determine failure rates atdifferent drift conditions under accelerated test conditions. Aformula for the factor containing both relative humidity andtemperature could be established and was found to hold also formeasurements published by others.</p><p>Electrostatic discharge (ESD) transients were studiedexperimentally and by simulation with good agreement. A verysensitive method to detect latent failures of two kinds wasintroduced by nonlinearity measurements utilizing the thirdharmonic of a test signal. The ESD-susceptibility dependence ondesign and technology is shown and can be used to improvebuilt-in reliability.</p><p>Influences in the performance of semiconductor devices fromdefects like fixed charges and ions were interpreted for thefirst time by simulation using a 2D- finite element componentprogram. Significant results gave an application to a MOSFETdevice showing parameter derating, especially the change of thethreshold value. A short description of later development insimulation methods with new, more powerful tools improvingcomponent performance and reliability is given.</p><p>Charged thin films of Teflon, so called<i>electrets</i>, are used as microphone membranes. Theelectret voltage is a suitable reliability factor. Fromexperimental results a mathematical relation including thetemperature was established for the rate of decay of theelectret voltage with time. A method to charge the electretswith radioactive sources is outlined and described in apatent.</p><p>Finally an attempt was done to analyze the reliability ofthin film circuits by mathematical methods. Bell Labsintroduced<i>RC</i>-feedback filters realized in tantalum thin filmtechnology. The phase shift of the filter is about π or180°. A mathematical apparatus was developed to calculatethe change in frequency and attenuation from small componentvariations in resistors and capacitors. First and higher ordercorrections were derived, using expansion by the Taylor seriesfor the higher order.</p><p><b>Keywords:</b>reliability, failure mechanism, accelerationtests, ESD, latent failure, plastic encapsulation, electret,thin film</p>

Low-energy electron scattering was used as a tool to study electron-stimulated processes at complex interfaces. The electron diffraction in each complex interface is theoretically treated by a multiple scattering formalism for quantitative analysis. Mathematical descriptions of electron-stimulated processes and a multiple scattering expansion extended from the single-scattering case are presented. This analysis method was applied in three research topics: These are 1) electron-stimulated desorption of Cl+ from Si surfaces, 2) characterization of epitaxial graphene on Si-terminated SiC(0001), and 3) low-energy electron induced DNA damage. Zone-specific desorption of Cl+ from Si(111)- 7X7:Cl surfaces was demonstrated. Graphene epitaxially grown on SiC(0001) surfaces was analyzed using Auger electron diffraction and Raman scattering spectroscopy. Finally, the roles of interfacial water and dissociative electron attachment resonances in low-energy electron-induced DNA damage were revealed. Electron scattering calculations using the "path approach" were applied in all of the above mentioned studies. The combination of theory and experiment has lead to insight regarding electron scattering with complex targets.

Focusing on the ‘Sustainable schools’ strategy, a programme launched in 2006 by the former United Kingdom government, this thesis examines the relationship between sustainable development and schools. It analyses how the abstract and contested concept of sustainable development (Scott & Gough 2003), is translated into education practices in state-funded primary schools in England and Portugal. The collection of data in two different countries is explained by the fact that it was in England that the ‘Sustainable schools’ policy was developed. Portugal was selected due to a requirement from my Portuguese sponsor, providing a valuable opportunity to explore the role of the context in the development of education for sustainable development (ESD) in primary schools. Taking a sociological approach, this study explores the practices of education for sustainable development and the factors that shape those practices. It looks at the way schools make choices, what they prioritise, and what the key elements influencing the development of ESD are. ‘What does one want ESD for?’; this is the underlying question behind the research, and so practices are contrasted with motivations, interests, agendas and expected outcomes. There is no single definition of ESD, given the complexity involved, and so to accept the importance of the concept of sustainability for education is to accept something that constitutes a problem (Corcoran & Wals 2004). Sustainability itself is a normative ethical principle, not a scientific concept as such, and since it has both necessary and desirable characteristics, there is no single model of a sustainable society (Robinson 2001). By providing robust data on how schools interpret, organise, decide, and implement ESD, my research contributes to the discussion of the role of schools in the transition to a ‘fairer and greener’ world. Literature claims, policy ideas and school practices are compared and contrasted with the aim of ‘demystify’ ESD and question the intentions, the expectations and the projected ESD outcomes The key research question of this study aims to identify the limitations of ESD in the shift to a ‘greener and fairer’ world. In order to do that, this thesis researched three other sub-questions: a) how is sustainability translated into practice in state-funded primary schools? b) how important is the promotion of ESD in primary schools’ agendas? and c) how was the ‘Sustainable schools’ project designed to prepare pupils for current and future environmental and social challenges. On the search for answers, several dilemmas were identified: of teaching about sustainable development versus practising it; of promoting critical thinking versus promoting specific knowledge, values and behaviours; of accepting the sustainable development concept or challenging it; of reducing the school’s environmental impact or developing the curriculum. These must all be faced by those dealing with ESD. Using a mixed methods approach, I explored these particular issues by researching five state-funded primary schools in England, some of which considered exemplary of the best practice of ESD. The case-studies research was followed by an online questionnaire sent to selected schools in England and Portugal. The questionnaire was used mainly to develop further the understanding of the results gathered with the case studies, providing a more robust image of ESD practices and its context. My research concludes that schools value ESD and tend to deal with its complexity by dividing the main ideas within the concept of sustainable development, into specific themes and activities, such as recycling, turning off lights or growing vegetables. The development of the school’s grounds, the investment in eco-features, and the activity-based projects are the most common practices found in the different schools. In this sense, there is a significant degree of standardisation in the projects developed, combined with a diverseness of specificities explained by the context, or the way the diverse factors, such as the location, the size, and the resources of the school, are used and combined. The limitations of ESD in the shift to a ‘greener and fairer’ world are plentiful, related to schools’ internal and external constraints, revealing the need to adjust expectations and resources to the projects developed by schools.

No description available.

The thesis introduces new semiconductor structures that are used as protections against Electrostatic Discharge occuring in integrated circuits. The fundamental structure for modeling and simulation has been lateral Silicon Controlled Rectifier. This SCR structure has been modificated to enable tuning of the triggering and holding voltages by changing geometrical mask dimensions. On the base of modeling and simulation the new proposed structures have been published. Also several protection structures have been designed to be manufactured and measured on a testchip. The final electrical behavior has been verified by measurement. Finally, the focus has been aided to protection circuit with bipolar transistor. This approach has been also simulated and verified by measurement. Advantages and disadvantages of the proposed protection structures are commented in the thesis.

Electrostatic Discharge (ESD) phenomenon is a common phenomenon in daily life and it could damage the integrated circuit throughout the whole cycle of product from the manufacturing. Several ESD stress models and test methods have been used to reproduce ESD events and characterize ESD protection device's performance. The basic ESD stress models are: Human Body Model (HBM), Machine Model (MM), and Charged Device Model (CDM). On-chip ESD protection devices are widely used to discharge ESD current and limit the overstress voltage under different ESD events. Some effective ESD protection devices were reported for low speed circuit applications such as analog ICs or digital ICs in CMOS process. On the contrast, only a few ESD protection devices available for radio frequency integrated circuits (RF ICs). ESD protection for RF ICs is more challenging than traditional low speed CMOS ESD protection design because of the facts that: (1) Process limitation: High-performance RF ICs are typically fabricated in compound semiconductor process such as GaAs pHEMT and SiGe HBT process. And some proved effective ESD devices (e.g. SCR) are not able to be fabricated in those processes due to process limitation. Moreover, compound semiconductor process has lower thermal conductivity which will worsen its ESD damage immunity. (2) Parasitic capacitance limitation: Even for RF CMOS process, the inherent parasitic capacitance of ESD protection devices is a big concern. Therefore, this dissertation will contribute on ESD protection designs for RF ICs in all the major processes including GaAs pHEMT, SiGe BiCMOS and standard CMOS. iv The ESD protection for RF ICs in GaAs pHEMT process is very difficult, and the typical HBM protection level is below 1-kV HBM level. The first part of our work is to analyze pHEMT's snapback, post-snapback saturation and thermal failure under ESD stress using TLP-like Sentaurus TCAD simulation. The snapback is caused by virtual bipolar transistor due to large electron-hole pairs impacted near drain region. Postsnapback saturation is caused by temperature-induced mobility degradation due to IIIV compound semiconductor materials' poor thermal conductivity. And thermal failure is found to be caused by hot spot located in pHEMT's InGaAs layer. Understanding of these physical mechanisms is critical to design effective ESD protection device in GaAs pHEMT process. Several novel ESD protection devices were designed in 0.5um GaAs pHEMT process. The multi-gate pHEMT based ESD protection devices in both enhancementmode and depletion-mode were reported and characterized then. Due to the multiple current paths available in the multi-gate pHEMT, the new ESD protection clamp showed significantly improved ESD performances over the conventional single-gate pHEMT ESD clamp, including higher current discharge capability, lower on-state resistance, and smaller voltage transient. We proposed another further enhanced ESD protection clamp based on a novel drain-less, multi-gate pHEMT in a 0.5um GaAs pHEMT technology. Based on Barth 4002 TLP measurement results, the ESD protection devices proposed in this chapter can improve the ESD level from 1-kV (0.6 A It2) to up to 8-kV ( > 5.2 A It2) under HBM. v Then we optimized SiGe-based silicon controlled rectifiers (SiGe SCR) in SiGe BiCMOS process. SiGe SCR is considered a good candidate ESD protection device in this process. But the possible slow turn-on issue under CDM ESD events is the major concern. In order to optimize the turn-on performance of SiGe SCR against CDM ESD, the Barth 4012 very fast TLP (vfTLP) and vfTLP-like TCAD simulation were used for characterization and analysis. It was demonstrated that a SiGe SCR implemented with a P PLUG layer and minimal PNP base width can supply the smallest peak voltage and fastest response time which is resulted from the fact that the impact ionization region and effective base width in the SiGe SCR were reduced due to the presence of the P PLUG layer. This work demonstrated a practical approach for designing optimum ESD protection solutions for the low-voltage/radio frequency integrated circuits in SiGe BiCMOS process. In the end, we optimized SCRs in standard silicon-based CMOS process to supply protection for high speed/radio-frequency ICs. SCR is again considered the best for its excellent current handling ability. But the parasitic capacitance of SCRs needs to be reduced to limit SCR's impact to RF performance. We proposed a novel SCR-based ESD structure and characterize it experimentally for the design of effective ESD protection in high-frequency CMOS based integrated circuits. The proposed SCR-based ESD protection device showed a much lower parasitic capacitance and better ESD performance than the conventional SCR and a low-capacitance SCR reported in the literature. The physics underlying the low capacitance was explained by measurements using HP 4284 capacitance meter. vi Throughout the dissertation work, all the measurements are mainly conducted using Barth 4002 transimission line pulsing (TLP) and Barth 4012 very fast transmission line pulsing (vfTLP) testers. All the simulation was performed using Sentaurus TCAD tool from Synopsys.

Ces travaux s'inscrivent dans un contexte où les contraintes vis-à-vis des décharges électrostatiques sont de plus en plus fortes, les circuits de protection sont un problème récurrent pour les circuits fonctionnant à hautes fréquences. La capacité parasite des composants de protection limite fortement la transmission du signal et peut perturber fortement le fonctionnement normal d'un circuit. Les travaux présentés dans ce mémoire font suite à une volonté de fournir aux concepteurs de circuits fonctionnant aux fréquences millimétriques un circuit de protection robuste présentant de faibles pertes en transmission, avec des dimensions très petites et fonctionnant sur une très large bande de fréquences, allant du courant continu à 100 GHz. Pour cela, une étude approfondie des lignes de transmission et des composants de protection a été réalisée à l'aide de simulations électromagnétiques et de circuits. Placés et fragmentées le long de ces lignes de transmission, les composants de protection ont été optimisés afin de perturber le moins possible la transmission du signal, tout en gardant une forte robustesse face aux décharges électrostatiques. Cette stratégie de protection a été réalisée et validée en technologies CMOS avancées par des mesures fréquentielles, électriques et de courant de fuite. / Advanced CMOS technologies provide an easier way to realize radio-frequency integrated circuits (RFICs). However, the lithography dimension shrink make electrostatic discharges (ESD) issues become more significant. Specific ESD protection devices are embedded in RFICs to avoid any damage. Unfortunately, ESD protections parasitic capacitance limits the operating bandwidth of RFICs. ESD protection size dimensions are also an issue for the protection of RFICs, in order to avoid a significant increase in production costs. This work focuses on a broadband ESD solution (DC-100 GHz) able to be implemented in an I/O pad to protect RFICs in advanced CMOS technologies. Thanks to the signal transmission properties of coplanar / microstrip lines, a broadband ESD solution is achieved by implementing ESD components under a transmission line. The silicon proved structure is broadband; it can be used in any RF circuits and fulfill ESD target. The physical dimensions also enable easy on-chip integration.

Allt levande på jorden är beroende av de tillgångar som erhålls av naturens olika ekosystem. På senare tid har dock människans påverkan på miljön och naturen fått stora konsekvenser som utsätter livet på jorden för fara. Mot denna bakgrund har ett intresse utvecklats för hur lärare bedriver undervisning om hållbar utveckling i syfte att utbilda samhällsmedborgare som besitter handlingsberedskap och konsekvenstänkande. Syftet med studien är därför att undersöka och analysera hur lärare undervisar ämnesövergripande om hållbar utveckling i NO och teknik i årskurs 4-6, samt vilken inställning lärare har till vikten av att behandla hållbar utveckling i dessa åldrar. De forskningsfrågor som används handlar om hur undervisningen organiseras, hur den bedrivs med fokus på de didaktiska frågorna vad, hur och varför samt hur lärarna beskriver att elever mottar undervisning om hållbar utveckling. För att uppnå syftet används en kvalitativ metod i form av semistrukturerade intervjuer med åtta lärare i Sävsjö kommun. Materialet analyseras med hjälp av metoden kvalitativ innehållsanalys. Genom att använda grundtankar ur det sociokulturella perspektivet och gestaltad didaktik möjliggörs ett djup i materialanalysen. Resultatet visar att lärarna i studien anser att hållbar utveckling är ett viktigt ämnesinnehåll i årskurs 4-6. Vidare framhävs att lärarna är medvetna om lärandemiljöns betydelse för inlärning och konkreta exempel ges på hur samtliga lärare arbetar ämnesövergripande om hållbar utveckling i NO och teknik. Lärarna uttrycker att det finns eventuella hinder för ämnesövergripande arbete med hållbar utveckling, men samtidigt är de fördelar som räknas upp övervägande i förhållande till antalet hinder. I beskrivningen av hur elever uppfattar undervisning om hållbar utveckling visar resultatet att de flesta är medvetna och engagerade. Slutsatsen är att ämnesövergripande arbete är positivt för elevers utvecklande av helhetsförståelse för hållbar utveckling. / Life on earth is depending on the assets received from different ecosystems. Lately, the human impact on the environment and nature has resulted in enormous consequences that imply danger to life on earth. Due to this fact, an interest evolved towards how education for sustainable development conducts with the aim to educate citizens to take action and think about the consequences of their choices. The aim of this study is therefore to investigate and analyse how teachers teach sustainable development interdisciplinary in science and technology in grades 4-6 and how important it is according to the teachers. The research questions that are being used is about how education is organized, how it is conducted with focus on the didactic questions what, how and why and how students receive education for sustainable development according to the teachers. To achieve the aim of the study it is carried through by a qualitative method in form of semi-structured interviews with eight teachers in the county of Sävsjö in Sweden. The material is analysed through qualitative content analysis. By using fundamental ideas from the sociocultural perspective on learning and didactics in terms of concretized teaching and learning a wider analysis is enabled. The result indicates that the teachers in the study think that education for sustainable development is important in grades 4-6. Furthermore, it is highlighted that the teachers are conscious about the importance of different learning environments and concrete examples of how all teachers work interdisciplinary with sustainable development in science and technology is presented. The teachers express that there are some eventual problems with teaching sustainable development interdisciplinary, however the positive aspects that are mentioned is predominant in relation to the problems. The description of how students receive education for sustainable development is mostly positive since they are conscious and dedicated. The conclusion is that interdisciplinary teaching is positive in developing students holistic understanding of sustainable development.