In this paper, an investigation of silicon nanocrystals-based sandwiched slot waveguides which are dispersion engineered for exciting optical solitons inside very short structures (only 3 mm long) is proposed. The possibility of using these structures for efficient surface sensing devices has been explored for the first time in cases of either air or water solution cover.

In this paper, a resonant sensor formed by a silicon-on-insulator waveguiding Bragg grating ring resonator working in linear and non-linear regime is proposed. In linear regime, the device shows a spectral response characterized by a photonic band gap (PBG). Very close to the band gap edges, it exhibits split resonant modes having a splitting magnitude equal to the PBG spectral extension, which is almost insensitive to the fabrication tolerances. When the device operates in nonlinear regime, exactly in that spectral region showing the split resonant mode structure, the sensing performance is strongly improved. This improvement has been demonstrated through a detailed model based on a set of full-vectorial equations taking into account not only all non-linear effects excited in the integrated silicon structure (i.e. Two Photon Absorption (TPA), TPA-induced Free Carrier Absorption, plasma dispersion, Self-Phase-Modulation and Cross-Phase-Modulation effects as induced by Kerr nonlinearity), but also the deleterious thermal and stress effects affecting the sensor performance.

A DC model of Carbon Nanotube Field Effect Transistors (CNTFETs) for CAD applications is proposed. The main objective is to obtain a very good agreement between measured and simulated I-V curves through a best-fitting procedure, particularly in the knee and saturation regions. To verify the accuracy of the model, the results have been compared with those of experimental data and of a numerical model online available, obtaining a negligible relative error in both cases. The proposed model can be easily implemented in an electrical simulator and the computational time is very short.

We present a compact, semi-empirical model of Carbon Nanotube Field Effect Transistors (CNTFETs) directly and easily implementable in simulation software. A new procedure, based on a best-fitting between the measured and simulated values of output device characteristics, is proposed in order to extract the optimal values of the CNTFET equivalent circuit elements. To verify the versatility of the proposed model, we use it in circuit simulators to design some electronic circuits. In particular we investigate about the effects of the CNT quantum resistances and inductances, then demonstrating their role for both analog and digital applications at frequencies over about ten THz.

In this paper we present a comparison among I-V models of CNTFETs proposed in literature in order to determine the model more easily implementable in simulation software for electronic circuit design. We have compared the CNTFETs model, already proposed by us, with Deng-Wong’s and Koswatta’s models. In particular our model, already structured to implement in simulator software, has been modified to characterize the I-V characteristics of CNTFETs below threshold. In this way it has been possible to have a more complete comparison, because the examined models consider the behaviour of device in sub-threshold regime.In spite of other models, our model seems to allow an easier implementation in the computer aided design of the most common analogue and digital circuits, showing a good agreement between the experimental and simulated characteristics, with processing times practically instant.

In this paper a simple procedure to determine the electronic properties of Carbon NanoTubes (CNTs) is proposed. In particular the model allows to evaluate the dispersion relationship and is based on the application to band-structure calculation of both of them the tight-binding approximation and the theory of Linear Combination of Atomic Orbitals (LCAO), obtaining a reduction of computational time compared to other methods proposed in literature, without losing in accuracy.

We present a compact, semiempirical model of carbon nanotube field effect transistor easily implementable in simulation SPICE software to design analog and digital circuits. The model is based on analytical approximations and parameters extracted from quantum mechanical simulations, having compared the results with those of the numerical model online available and of experimental data.

In this paper we present a simple model of Carbon Nanotube Field Effect Transistors (CNTFETs), whose main objective is to obtain a very good agreement between measured and simulated I-V curves through a best-fitting procedure, particularly in the knee and saturation regions. To verify the accuracy of the model, the results have been compared with those of experimental data and of a numerical model online available.

The fiber optic transmission systems require a bandwidth of about 25 THz in the networks of telecommunications, for which it is necessary to resort to Dense Wavelength Division Multiplexing (DWDM) systems. These systems need optical filters to broadcast selectively or not in a given wavelength band. A very promising technology for these applications is the Photonic Crystals with forbidden band-gap (Photonic Band-Gap, PBG). In this chapter a powerful and efficient model to characterize photonic band-gap structures incorporating multiple defects, having arbitrary shape and dimensions, is reviewed. The importance of the defect-mode characterization in photonic band-gap materials is due to the intensive use of defects for light localization to design very promising optical devices. The model, based on the Leaky Mode Propagation method (LMP), provides to model defects in wave-guiding, finite-size photonic band gap devices and analytical and closed-form expressions for the reflection and transmission coefficients and out-of-plane losses, very useful and easy to be implemented for any operating conditions. Moreover, the method, implemented in a very fast code in FORTRAN 77 language, running on a personal computer, has been applied to look into the capabilities of wave-guiding photonic band gap devices in DWDM filtering applications. In particular the design of some optical filters has been carried out and optimal design rules have been drawn using the reviewed model.

In this paper we presents a DC thermal model of recessed gate P-HEMTs in which we propose several issues to allow an easy implementation in circuit simulators. In particular we identify transistor thermal parameters, which have greater influence on the device behaviour. In order to verify the accuracy of the proposed model, the results are compared with those of a model, already proposed, obtaining a negligible relative error. However the proposed simplified model can be easily used for CAD applications, with computational time very short.

In this paper we present a new medical device for cardioholter applications intended to overcome the limitations actually present in the commercial devices and to advance the state of the art. In particular we propose a system for ECG transmission by Bluetooth, embedded in a digital cardioholter with multiple leads. The system has been designed, prototyped and tested at the Electronic Devices Laboratory (Electrical and Information Engineering Department) of Polytechnic University of Bari, Italy, within a biomedical researcher program, sponsored by Italian Government.

In this work we propose an innovative system, which allows to the doctor to carry out a complete cardio-respiratory control on remote patients in real time. The proposed system, prototyped at the Electronic Devices Laboratory (Department of Electrical and Information Engineering) of Polytechnic University of Bari, Italy, has been also verified by the heart specialists of the U.O. of Cardiology in the General Hospital (Polyclinic) of the University of Bari, Italy.

In this paper we present an electronic system to perform a non-invasive measurement of the blood pressure based on the oscillometric method, which does not suffer from the limitations of the well-known auscultatory one. Moreover the proposed system is able to evaluate both the systolic and diastolic blood pressure values and makes use of a microcontroller and a Sallen-Key active filter. With reference to other similar devices, a great improvement of our measurement system is achieved since it performs the transmission of the systolic and diastolic pressure values to a remote computer. This aspect is very important when the simultaneous monitoring of multi-patients is required. The proposed system, prototyped and tested at the Electron Devices Laboratory (Electrical and Information Engineering Department) of Polytechnic University of Bari, Italy, is characterized by originality, by plainness of use and by a very high level of automation (so called “intelligent” system).

In this paper we have implemented the semi-empirical compact model for CNTFETs already proposed by us both in SPICE, using ABM library, and in Verilog-A in order to compare them. Typical analogue circuits and logic blocks have been simulated and results have been presented to validate the implementation of the proposed CNTFET model both in Verilog-A and in SPICE. The obtained results have been the same in static simulations and comparable in dynamic simulations, in which the differences are due to the better implementation of the capacitance model in Verilog-A. We have found many advantages using Verilog-A: the development time in writing the model is shorter, the simulation run time much shorter and the software is much more concise and clear than schemes using ABM blocks in SPICE.

In this paper we propose a new architecture of a non-invasive, continuous blood glucose monitoring system, based on dielectric spectroscopy. In particular we design the electrical circuit, the schematic and the PCB of a mixed signal system working in a frequency range 1 MHz – 160 MHz, where the best performances in terms of electrical changes in the blood can be achieved. The proposed architecture allows to acquire easily the dependence on frequency for both amplitude and phase of the dielectric constant from which the glucose levels in blood is estimated.

The aim of this paper is to present a comparison of electro-thermal performance of two HBTs based on Si/SiGe and on AlGaAs/GaAs, by means of an analytical electro-thermal model, already proposed by us, able to calculate the temperature and current distribution for any integrated device, whose structure can be represented as an arbitrary number of superimposed layers with a 2-D embedded thermal source

In this paper a new sensor for the non-invasive monitoring of the oxygen saturation in blood has been designed, realized and tested to obtain an ultra-small device having very high noise immunity. This goal has been reached by using a particular integrated circuit, the PsoC (Programmable System on Chip), which integrates two programmable arrays, one analogue and one digital, to obtain a device with very large capabilities. We have configured the PsoC and developed the electronic interfaces. The proposed design allows the acquisition of the continuous component of the signal and the data elaboration has been done in place using a local CPU, without requiring to pass data to an external computer.

In this chapter an analytical model to optimize the thermal and electrical layout for multilayer structure electronic devices is reviewed. The model is based on the solution to the non-linear 3-D heat equation. The thermal solution is achieved by the Kirchhoff transform and the 2-D Fourier transform. The electro-thermal feedback is implemented by calculating the device current at the actual channel temperature. The model is general and can be easily applied to a large variety of integrated devices, provided that their structure can be represented as an arbitrary number of superimposed layers with a 2-D embedded thermal source, so as to include the effect of the package. This subject is very important for device designers, provided that the algorithm is reliable and not too difficult to realize practically. Moreover the model is independent on the specific physical properties of the layers, hence GaAs FETs, HBT and HEMTs as well as Silicon and Silicon-On-Insulator MOSFETs and heterostructure LASERs can be analysed.

Il presente volume costituisce una breve sintesi degli argomenti, trattati in modo completo ed esaustivo, nei miei libri, già pubblicati con la Casa Editrice Progedit: “Fondamenti di Dispositivi Elettronici” (2010) e “Dispositivi Elettronici Avanzati” (2011). Tali argomenti, che vanno dalle proprietà elettroniche dei materiali semiconduttori sino ai dispositivi FET in Si ed in GaAs, tra cui i MESFET con buffer in AlGaAs e gli HEMT, sono esposti in termini di formule essenziali ma esaustive, allo scopo di aiutare il lettore nelle applicazioni di analisi e progetto dei dispositivi elettronici. Inoltre, poiché la progettazione dei circuiti elettronici si avvale sempre più largamente delle tecniche CAD, ho ritenuto opportuno introdurre nella seconda parte del libro un breve manuale di avvio all'utilizzo di PSPICE, fornendo gli elementi essenziali per il progetto full-custom dei circuiti integrati, attraverso diversi esempi di simulazione circuitale, al fine di consentire al lettore di esercitarsi riproducendo ed arricchendo i risultati ottenuti. Nelle mie intenzioni è che questo libro, destinato agli studenti dei Corsi di Laurea Triennale e Magistrale in Ingegneria Elettronica, Fisica e Scienza dei Materiali, possa costituire un valido aiuto anche per i tecnici e studiosi che si occupano di progettazione elettronica.

Il volume è dedicato allo studio dei meccanismi di funzionamento dei dispositivi elettronici più avanzati. In particolare vengono presi in esame dispositivi elettronici basati su eterogiunzioni (Cap. 1), quali HBT (Cap. 2), MESFET ed HEMT (Cap.3), illustrandone gli aspetti innovativi e mettendo in evidenza anche i risultati più originali ed interessanti della mia ricerca nel settore della fisica, caratterizzazione e modellistica dei dispositivi in GaAs, svolta in un trentennio di attività universitaria. Per ciascun dispositivo sono esaminati i modelli matematici necessari per formalizzarne i principi fisici di funzionamento ed i vari modelli circuitali, per grandi e piccoli segnali e di rumore (Cap. 4). Una particolare attenzione viene posta ai modelli di dispositivi dedicati al CAD di circuiti integrati e nella descrizione dei cosiddetti “effetti del secondo ordine”. In questo ambito, un intero capitolo (Cap. 5), dedicato all’analisi ed al progetto full-custom dei circuiti integrati con l’ausilio del calcolatore, rappresenta una utile e veloce guida all’impiego del simulatore PSPICE. Il Cap. 6 affronta lo studio delle principali tecniche di processo per la realizzazione di circuiti ULSI. In particolare vengono studiati i dispositivi bipolari e MOS nanometrici, mettendo in evidenza le problematiche connesse ad una miniaturizzazione spinta del dispositivo e le soluzioni tecnologiche previste. Nel Cap. 7, dal momento che le memorie a semiconduttore hanno assunto un ruolo sostanziale nell’attuale scenario tecnologico mondiale, mi è sembrato opportuno esaminare alcune delle tecnologie impiegate per realizzare dispositivi per le memorie, a partire dalla classica struttura del MOS floating gate, del FLOTOX, del MNOS, del SONOS, proseguendo per le innovative memorie a nanocristalli fino ad arrivare alle memorie di ultimissima generazione ferroelettriche e magnetiche. Lo studio dei nanotubi di carbonio, con particolare riguardo ai CNTFET, e l’esame delle problematiche connesse all’insorgenza di effetti quantistici nei dispositivi nanoelettronici sono affrontati nei Cap. 8 e 9. Infine il Cap. 10 è dedicato all’esame dei principali dispositivi optoelettronici, con l’obiettivo di dare al testo connotazioni di completezza, per quanto possibile, in un settore così vasto e complesso. Nelle mie intenzioni è che il testo possa essere particolarmente adatto agli studenti dei Corsi di Laurea Magistrale in Ingegneria, Fisica e Scienza dei Materiali.

In recent years the Internet spreading has carried to an increasing request of wider band and electronic integration for telecommunication network. This aspect leads to define new technologies, as Photonic BandGap (PBG) crystals, in order to obtain a faster data treatment. PBG crystals are able to overcome the typical integration limits of traditional optical circuits, allowing a scale of integration similar to the electronic ULSI. PBG crystals are materials able to influence the light propagation analogously it occurs for the propagation of the electrons in semiconductors. In fact, in photonic crystals, to propagate some light quanta (or photons) a principle similar to what is seen for the semiconductor crystals will be exploited, as the crystal periodicity is artificially realized by means of alternation of dielectric macroscopic materials. According to their geometrical characteristics, photonic crystals inhibit the light propagation in one or more directions, depending on the working frequency: if so, a band gap exists, i.e. a frequency range in which the wave cannot propagate. The introduction of defects inside the periodical structure of a photonic crystal determines the forming of photonic states located in the gap. Such characteristic is exploited to carry out devices with high capabilities, for example optical micro-resonators (in which a column is removed) or low losses waveguides, which are based on the presence of a bandgap and not on the total internal reflection. In this paper, after a brief description of operation principle of photonic crystals, we present a review of the most important photonic crystals devices, describing, in particular, the main steps required to model and to design resonant cavities and particle accelerators.

In this paper we review an analytical electrothermal model, already proposed by us, able to calculate the temperature and current distribution for any integrated device, whose structure can be represented as an arbitrary number of superimposed layers with a 2-D embedded thermal source, so as to include the effect of the package. The model allows to optimize the device layout through the solution of the non-linear 3-D heat equation. The thermal solution is achieved by the Kirchhoff transform and the 2-D Fourier transform. Moreover the model is independent on the specific physical properties of the layers, hence GaAs FETs, HBT and HEMTs can be analysed. The model has been applied to characterize the electrical and thermal performances of a multifinger GaAs FET and of a Si/SiGe Heterojunction Bipolar Transistor.

Wireless power transmission using laser beaming can be realized with arrays of high power semiconductor laser diodes. In this paper we present a complete model for a single power emitter diode characterized by a tapered amplifying section and a quantum well active layer. The band mixing technique has been used for gain calculation and the Transmission Line Laser Modelling (TLLM) for evaluating the electromagnetic propagation inside a tapered waveguide. Moreover we present a complete time domain analysis, which allows to include non linear effects. The model has been completed with a proper set of rate equation for carrier distribution and sources to take into account the Amplified Spontaneous Emission (ASE) noise. A real device has been simulated and the results are reported and discussed. In particular we have demonstrated that mode conversion becomes overestimated when less than 600 sections are used in the proposed model, or when the step size is greater than 1.5 μm.

In this chapter we review a very accurate and fast model of Photonic Band-Gap (PBG) structure characterized by a two-dimensional (2D) periodic change of the refractive index and finite height, therefore named quasi 3D PBG. The model is based on the Floquet-Bloch formalism and allows to find all the propagation characteristics, including the space harmonics and the total field distribution, the propagation constants, the guided and radiated power and modal loss induced by the 2D grating. A clear explanation of the physical phenomena occurring when a wave propagates inside the 2D periodic structure is presented, including the photonic band gap formation and the radiation effects. The approach does not require any theoretical approximation, and can be applied to rigorously study any PBG-based multilayer structures. We have applied the model to investigate several structures for both optical and microwave applications.

The techniques used for the design of circuits for space applications are not different from those used for commercial applications. However the technology and the fabrication processes must be oriented to obtain an average life of the circuit and/or component higher than the expected service offered from the satellite. For these applications the Monolithic Microwave Integrated Circuit (MMIC) design techniques must satisfy requirements that include also specifications such as the reliability and the final production yield. In this chapter we review a MMIC design technique oriented to the optimization of the production yield. This method, based on a sensitivity analysis, i.e. on the circuit behavior for value variations of passive elements from their nominal value, and on the contemporary determination of the production yields, allows the identification the circuit elements to obtain high production yield. Moreover it allows an appropriate choice of the circuit topology. As example, this technique has been applied to design a MMIC to employ on a Synthetic Aperture Radar (SAR) in X band.

The aim of this paper is to model and characterize the current voltage characteristics of Schottky Barrier (SB) Carbon NanoTube Field Effect Transistors (SB-CNTFETs) below and above threshold, in order to evaluate the noise margin and output voltage swing, whose values are necessary in the design of digital circuits

In this paper we present the status and future challenges of ferroelectric and magnetic memories, which are the promise for dramatic improvements in the speed, endurance and power consumption of non-volatile semiconductor memories.

We present a model of Carbon NanoTube Field Effect Transistors (CNTFETs) directly and easily implementable in simulation SPICE software for electronic circuit design. The model is based on analytical approximations and parameters extracted from quantum mechanical simulations of the device and depending on the nanotube diameter and on the oxide capacitance. The comparison of the simulated output and transfer characteristics with those of a numerical model available online and with experimental data shows a relative error less than 5% in both cases. In order to determine the values of CNTFET equivalent circuit elements, a new procedure, based on a best-fitting between the measured and simulated values of output device characteristics, has been proposed. To verify the versatility of the proposed model, we use it in the SPICE simulator to design some A/D electronic circuits, demonstrating the importance of the quantum capacitance dependence on polarization voltages and examining the effects of the CNT quantum resistances.

In this chapter we analyze a compact, semi-empirical model of Carbon Nanotube Field Effect Transistors (CNTFETs) directly and easily implementable in simulation software. The model is based on the hypothesis of fully ballistic transport in a mesoscopic system between two non-reflective contacts and analytical approximations are introduced to avoid the resort to self-consistency. A new procedure, based on a best-fitting between the measured and simulated values of output device characteristics, is proposed. This procedure allows to extract, from the measured output characteristics of the device, the optimal values of the CNTFET equivalent circuit elements. To verify the versatility of the proposed model, we use it in circuit simulators to design some electronic circuits. In particular we investigate about the effects of the CNT quantum resistances and inductances, then demonstrating their role for both analog and digital applications at frequencies over about ten THz.

We review a compact, semi-empirical model of Carbon Nanotube Field Effect Transistors (CNTFETs), in which we have proposed several issues to allow an easy implementation in the most common circuit simulators. The CNTFET equivalent circuit is similar to a common MOSFET one, where the quantum capacitances have been computed from the charge in the channel. A new procedure, based on a best-fitting between the measured and simulated values of output device characteristics, is proposed in order to extract the optimal values of the CNTFET equivalent circuit elements. Moreover, in order to utilize the proposed model also in the design of basic digital circuits, we have modified our model to characterize the I-V characteristics of CNTFETs below threshold. Finally we have implemented our model both in SPICE, using ABM library, and in Verilog-A in order to compare them. Typical analogue circuits and logic blocks have been simulated and results have been presented to validate the implementation of the proposed CNTFET model both in Verilog-A and in SPICE. The obtained results have been the same in static simulations and comparable in dynamic simulations, in which the differences are due to the better implementation in Verilog-A of the intrinsic capacitance model.

Prediction through modelling forms the basis of engineering design. The computational power at the fingertips of the professional engineer is increasing enormously and techniques for computer simulation are changing rapidly. Engineers need models which relate to their design area and are adaptable to new design concepts. They also need efficient and friendly ways of presenting, viewing and transmitting the data associated with their models. This book collects five chapters and provides a detailed guide for the design and test of electronic and optoelectronic devices allowing engineers to simulate individual devices and electronic circuits and performing a large number of different analyses needed for tasks such as verification of circuit designs and prediction of circuit performance. A particular attention is devoted to scaling of transistors, which in the last half of century has been the driving force for electronics. A wide variety of devices are also being explored to complement or even replace silicon transistors at molecular scales. Similarities between nanoscale and microscale transistors exist, but nanotransistors also behave in drastically different ways. For example, ballistic transport and quantum effects become much more important. Moreover the downscaling of power integrated devices and the increase of the dissipated power density emphasise the importance of a proper thermal analysis during the design process. Particularly in GaAs technology, one of the main problems to overcome is the low thermal conductivity of the semiconductor, which focuses the designer’s interest both on the device layout and package thermal optimization when good reliability is to be achieved. Ideal as a reference for professional engineers or as a text for courses in electronic and optoelectronic device modelling, the proposed book presents: • a combination of background device physics and technology; • a review of existing device models; • a set of new and improved models compatible with the most advanced technology, which I have already proposed in literature during a period of over thirty years of my research activity; • descriptions of device models and examples of circuit simulations. In the first chapter an analytical model to optimize the thermal and electrical layout for multilayer structure electronic devices is reviewed. The model is based on the solution to the non-linear 3-D heat equation. The thermal solution is achieved by the Kirchhoff transform and the 2-D Fourier transform. In the second chapter the authors review a very accurate and fast model of Photonic Band-Gap (PBG) structure characterized by a two-dimensional (2D) periodic change of the refractive index and finite height, therefore named quasi 3D PBG. The model is based on the Floquet-Bloch formalism and allows to find all the propagation characteristics, including the space harmonics and the total field distribution, the propagation constants, the guided and radiated p

A Verilog-A compact model for Carbon NanoTube Field Effect Transistors (CNTFETs) has been implemented to study basic digital circuits. The model, based on the hypothesis of fully ballistic transport in a mesoscopic system between two non-reflective contacts, has been structured to allow an easy implementation in Verilog-A language and has been compared with experimental data, showing a good agreement between simulation and experimental results, particularly in the saturation region, where the relative error is practically negligible. Moreover the Verilog-A model has been utilized to design a digital NOT gate with complementary technology and a NAND gate, in which the quantum capacitance dependence on polarization voltages has been considered.