Devenlopment of Compact Small Signal Quasi Static Models for Multiple Gate Mosfets

En esta tesis hemos desarrollado los modelos compactos explícitos de carga y de capacitancia adaptados para los dispositivos dopados y no dopados de canal largo (DG MOSFETs dopados, DG MOSFETs no dopados, UTB MOSFETs no dopados y SGT no dopados) de un modelo unificado del control de carga derivado de la ecuación de Poisson. El esquema de modelado es similar en todos estos dispositivos y se adapta a cada geometría. Los modelos de la C.C. y de la carga son completamente compatibles. Las expresiones de la capacitancia se derivan del modelo de la carga. La corriente, la carga total y las capacitancias se escriben en términos de las densidades móviles de la carga en los extremos de fuente y drenador del canal. Las expresiones explícitas e infinitamente continuas se utilizan para las densidades móviles de la carga en la fuente y drenador. Las capacitancias modeladas demuestran el acuerdo excelente con las simulaciones numéricas 2D y 3D (SGT), en todos los regímenes de funcionamiento. Por lo tanto, el modelo es muy prometedor para ser utilizado en simuladores del circuito. Desafortunadamente, no mucho trabajo se ha dedicado a este dominio de modelado. Las cargas analíticas y las capacitancias, asociadas a cada terminal se prefieren en la simulación de circuito. Con respecto al SGT MOSFET, nuestro grupo fue el primero en desarrollar y publicar un modelo de las cargas y de las capacitancias intrínsecas, que es también analítico y explícito. La tesis es organizada como sigue: el capítulo (1) presenta el estado del arte, capítulo (2) el modelado compacto de los cuatro dispositivos: DG MOSFETs dopados, DG MOSFETs no dopados, UTB MOSFETs no dopados y SGT no dopados; en el capítulo (3) estudiamos las capacitancias de fricción en MuGFETs. Finalmente el capítulo (4) resuma el trabajo hecho y los futuros objetivos que necesitan ser estudiados. Debido a la limitación de los dispositivos optimizados disponibles para el análisis, la simulación numérica fue utilizada como la herramienta principal del análisis. Sin embargo, cuando estaban disponibles, medidas experimentales fueron utilizadas para validar nuestros resultados. Por ejemplo, en la sección 2A, en el caso de DG MOSFETs altamente dopados podríamos comparar nuestros resultados con datos experimentales de FinFETs modelados como DG MOSFETs. La ventaja principal de este trabajo es el carácter analítico y explícito del modelo de la carga y de la capacitancia que las hace fácil de implementar en simuladores de circuitos. El modelo presenta los resultados casi perfectos para diversos casos del dopaje y para diversas estructuras no clásicas del MOSFET (los DG MOSFETs, los UTB MOSFETs y los SGTs). La variedad de las estructuras del MOSFET en las cuales se ha incluido nuestro esquema de modelado y los resultados obtenidos, demuestran su validez absoluta. En el capítulo 3, investigamos la influencia de los parámetros geométricos en el funcionamiento en RF de los MuGFETs. Demostramos el impacto de parámetros geométricos importantes tales como el grosor de la fuente y del drenador o, el espaciamiento de las fins, la anchura del espaciador, etc. en el componente parásito de la capacitancia de fricción de los transistores de la múltiple-puerta (MuGFET). Los resultados destacan la ventaja de disminuir el espaciamiento entre las fins para MuGFETs y la compensación entre la reducción de las resistencias parásitas de fuente y drenador y el aumento de capacitancias de fricción cuando se introduce la tecnología del crecimiento selectivo epitaxial (SEG). La meta de nuestro estudio y trabajo es el uso de nuestros modelos en simuladores de circuitos. El grupo de profesor Aranda, de la Universidad de Granada ha puesto el modelo actual de SGT en ejecución en el simulador Agilent ADS y buenos resultados fueron obtenidos.In this thesis we have developed explicit compact charge and capacitance models adapted for doped and undoped long-channel devices (doped Double-Gate (DG) MOSFETs, undoped DG MOSFETs, undoped Ultra-Thin-Body (UTB) MOSFETs and undoped Surrounding Gate Transistor (SGT)) from a unified charge control model derived from Poisson's equation. The modelling scheme is similar in all these devices and is adapted to each geometry. The dc and charge models are fully compatible. The capacitance expressions are derived from the charge model. The current, total charges and capacitances are written in terms of the mobile charge sheet densities at the source and drain ends of the channel. Explicit and infinitely continuous expressions are used for the mobile charge sheet densities at source and drain. As a result, all small signal parameters will have an infinite order of continuity. The modeled capacitances show excellent agreement with the 2D and 3D (SGT) numerical simulations, in all operating regimes. Therefore, the model is very promising for being used in circuit simulators. Unfortunately, not so much work has been dedicated to this modelling domain. Analytical charges and capacitances, associated with each terminal are preferred in circuit simulation. Regarding the surrounding-gate MOSFET, our group was the first to develop and publish a model of the charges and intrinsic capacitances, which is also analytic and explicit. The thesis is organized as follows: Chapter (1) presents the state of the art, Chapter (2) the compact modeling of the four devices: doped DG MOSFETs, undoped DG MOSFETs, undoped UTB MOSFETs and undoped SGT; in Chapter (3) we study the fringing capacitances in MuGFETs. Finally Chapter (4) summarizes the work done and the future points that need to be studied. Due to the limitation of available optimized devices for analysis, numerical simulation was used as the main analysis tool. However, when available, measurements were used to validate our results. The experimental part was realised at the Microelectronics Laboratory, Université Catholique de Louvain, Louvain-la Neuve, Belgium. For example, in section 2A, in the case of highly-doped DG MOSFETs we could compare our results with experimental data from FinFETs modeled as DG MOSFETs. The main advantage of this work is the analytical and explicit character of the charge and capacitance model that makes it easy to implement in circuit simulators. The model presents almost perfect results for different cases of doping (doped/undoped devices) and for different non classical MOSFET structures (DG MOSFET, UTB MOSFETs and SGT). The variety of the MOSFET structures in which our modeling scheme has been included and the obtained results, demonstrate its absolute validity. In chapter 3, we investigate the influence of geometrical parameters on the RF performance in MuGFETs. We show the impact of important geometrical parameters such as source and drain thickness, fin spacing, spacer width, etc. on the parasitic fringing capacitance component of multiple-gate field-effect transistors (MuGFET). Results highlight the advantage of diminishing the spacing between fins for MuGFETs and the trade-off between the reduction of parasitic source and drain resistances and the increase of fringing capacitances when Selective Epitaxial Growth (SEG) technology is introduced. The goal of our study and work is the usage of our models in circuit simulators. This part, of implementing and testing our models of these multi gate MOSFET devices in circuit simulators has already begun. The group of Professor Aranda, from the University of Granada has implemented the SGT current model in the circuit simulator Agilent ADS and good results were obtained

The perspective of spatio-temporal variability of Romanian economy in European space

Interrelation of economic and financial phenomena and processes, characterized by varying degrees of intensity of events in time and space, generates, sometimes, difficulties for public authorities of all times, both economic and noneconomic nature. Disparities between countries and economic disparities and also the impact of adverse shocks on the economy represent in recent years an intense topic of debate for researchers and professionals, making up the analysis of their economic theories that shape it in time and space dynamics of various economic indicators. Since every economic size is characterized as spatial and temporal dimensions and relations of dependency with other economic indicators, the statistical approach to spatial and temporal variability of the Romanian economy, sought to highlight this trend compared with the EU, as level of development, we proposed using an index composed Romania - European Union. Outcomes show that the Romanian economy is not prepared to face competitive pressure from European Union forces, is still facing eternal problem of solving cyclical temporary shocks.economic and financial phenomena, economic disparities, cyclical temporary shocks

THE CONSTITUTIONAL AND LEGAL STATUS OF THE ROMANIAN COURT OF ACCOUNTS

In order to follow the way in which all incomes are charged and the expenses approved by the state budget are used, the Parliament has set up an independent and neutral specialised institution that is meant to exercise a detailed control over the formation, administration and use of all the financial resources of the state and of the public sector. This independent and neutral body is the Romanian Court of Accounts which represents an autonomous, central specialised authority, regulated by the IV Heading of the Romanian Constitution, revised and republished in 2003. Considering the necessity of strengthening the financial discipline in the formation, administration and use of public funds, the Court of Accounts (CoA) assumes its role of watchdog in upholding the law in all matters mentioned above. Such a role is even more important as besides national public funds there are also an important number of non-reimbursable credits granted to our country by the European Union. From this point of view, the CoA should reinforce its status of strong, fully independent institution with wide and complex responsibilities .Court of Accounts, constitution, independent and neutral body, central specialized authority, autonomous character, public funds, legality.

The Necessity of Reconsidering the Concept of Non-formal Education

AbstractReaching the educational finalities that derive from the educational ideal of the Romanian school, stipulated into the National Education Law no. 1/2011, article 1, line (3), is conditioned by the ensuring of a functional complementarity between the three forms of education: formal, non-formal and informal.In the present study we suggest both a re-consideration and a re-signification of the concept of non-formal education taking into consideration the current educational paradigms, the conceptual, curricular and methodological current evolutions and the legal context

Historical Biogeography of Subterranean Beetles – “Plato’s Cave” or Scientific Evidence?

The last two decades were particularly prolific in historical biogeography because of new information introduced from other sciences, such as paleogeography, by the development of quantitative methods and by molecular phylogeny. Subterranean beetles represent an excellent object of study for historical biogeography because they are the group with the best representation in the subterranean domain. In addition, species have reduced mobility, display different degrees of adaptations to life in caves and many specialists work on this group. Three processes have shaped the present distribution of the tribe Leptodirini (Coleoptera Cholevinae) in the world: dispersal, vicariance, and extinction. Therefore, three successive stages can be established in the space-time evolution of Leptodirini: (1) dispersal from a center of origin in the present area(s); (2) dispersal, extinction and vicariance among the present area(s); and (3) colonization and speciation in the subterranean domain. The Romanian Leptodirini, especially those from Western Carpathians is examined with respect to these processes. Their pattern of distribution in different massifs and at different altitudes is discussed, with possible explanations from a historical biogeographic point of view

Financial instruments designed to increase the competiveness of the European firms

In the new global economy based on knowledge, the maintenance, the increase of life standards and social stability is related to the assurance of competitiveness of the economic structures of any state,regardless their constitutional order and system administration or whether they belong or not to a form of association. The nowadays financial and economic crisis has increased transparency, but it also amplified by contagion the negative effects of structural disparities between different areas and regions spatially dispersed. Anticipating economic and social change, the Member States have decided to restructure the priorities of the resources allocated through the Community financial instruments and programs. They complete the efforts of the European states, towards increasing the competitiveness, which becomes the basic resource for sustainable economic growth. Methods of collecting and processing data and information highlights the performance gaps of the Union at the economic and financial triad, showing the existence of structural problems increased by the last two expansions, the globalization of the market, the demographic decline and the population aging

Correlation between electoral cycle and fiscal policy decisions in Romania

Economic reality has shown that current enforcement techniques will produce the desired finalities, avoiding distortion under psychological decision of all members of society and reduce the current costs of tax administration. Therefore, taxation is the product of social factors, which determine, before any other factors widely and work closely on the social physiognomy, which causes various and numerous effects, that could be considered synthetic, two-way, as expressed sequence all taxpayers reactions taxes, such as tastes and scale transformation of values, the redistribution of costs, savings, debt and changing conditions of work and life, in general.The functioning of a democratic regime depends not only institutions which carry out the division of labor between the executive and legislature, but also of a number of formal rules and informal procedures through which political actors influence the operation of the system. The objective is to provide some empirical evidencies of relation between fiscal policy and electoral cicles. The main output consist in this thesis that some support could be found for this, in Roumania

PRIORITETI UPRAVLJANJA JAVNIM KOMUNALNIM USLUGAMA U ZAPADNOJ RUMUNJSKOJ

Public utility services are an important vector for the development of regional and local communities. Providing these services is equally important to citizens, central, regional and local authorities, and academics. The management of public utility services needs to be completed in the spirit of an efficient and performant process. This paper highlights the perception of the users of public utility services regarding the quality of various public services. Also, it identifies potential improvement measures that can be adopted by the authorities with competences in the field of utility services. In this respect, we apply a methodology based on the survey method, considering a sample of 220 respondents, between December 2014 and April 2015 at the level of the Western Region of Romania, namely the counties of Timis, Caras-Severin, Arad and Hunedoara. The main conclusion of the study reveals users’ dissatisfaction with the quality of public utility services provision, as well as the lack of communication between authorities and citizens.The results of the present paper can form a basis for well-grounded proposals for efficient measures which need to be implemented by local and regional authorities in order to improve the provision of public utility services.Javne komunalne usluge važan su vektor razvoja regionalnih i lokalnih zajednica. Te usluge jednako su važne građanima, središnjim, regionalnim i lokalnim vlastima, ali i akademskoj zajednici. Upravljanje javnim komunalnim uslugama mora biti učinkovit i djelotvoran proces. Ovaj rad bavi se percepcijom kvalitete javnih komunalnih usluga od strane njihovih korisnika. Također navodi moguće mjere za poboljšanje tih usluga koje mogu uvesti tijela nadležna za upravljanje komunalnim uslugama. U radu se koristi metoda ankete te se analizira uzorak odgovora 220 ispitanika prikupljenih u razdoblju od prosinca 2014. do travnja 2015. u zapadnoj Rumunjskoj, točnije u općinama Timis, Caras-Severin, Arad i Hunedoara. Zaključak studije otkriva nezadovoljstvo korisnika kvalitetom pružanja javnih komunalnih usluga, ali i nedostatak komunikacije između nadležnih tijela i građana. Rezultati ovog rada mogu biti temelj za predlaganje mjera koje lokalne i regionalne vlasti mogu provesti kako bi poboljšale kvalitetu komunalnih usluga