bluuebunny/crossref_metadata_2025 huggingface dataset:
FERROELECTRIC NONVOLATILE MEMORY FIELD-EFFECT TRANSISTORS BASED ON A NOVEL BUFFER LAYER STRUCTURE
Authors: KIM HONG KOO , BASIT NASIR ABDUL
Published: April 2003

We have proposed and developed a ferroelectric nonvolatile field-effect transistor that incorporates a thin MgO buffer layer between a ferroelectric film and an oxidized Si substrate. The use of an MgO/SiO2 buffer for a ferroelectric gate is based on the following findings. First, a thin MgO buffer serves well as a template layer allowing the growth of highly oriented ferroelectric films on amorphous substrates. Second, MgO works well as a diffusion barrier between a ferroelectric film and a substrate, protecting the silicon FET channel region from interdiffusion or reaction that may occur during device processing. Third, thermal oxidation of Si is known to be one of the best ways of passivating silicon surfaces, thus to reduce high quality FET channels. The fabricated devices show excellent performance in ferroelectric polarization switching, memory retention, and fatigue resistance. The devices also demonstrate scalability in device dimension and operating voltage, i.e., they are suitable for low voltage operation (3-5 V or below) showing a sufficient memory window (1-2 V).
VLSI-COMPATIBLE PROCESSING AND LOW-VOLTAGE OPERATION OF MULTIEMITTER Si/SiGe HETEROJUNCTION BIPOLAR TRANSISTORS
Authors: ZASLAVSKY A. , MASTRAPASQUA M. , KING C. A. , JOHNSON R. W. , PILLARISETTY R. , LIU JUN , LURYI S.
Published: April 2003

Previously we demonstrated a new class of VLSI-compatible multiemitter Si/SiGe/Si npn HBTs with enhanced logic functionality. These devices have two (or more) emitter contacts and no base contact. Given a potential difference between any two emitter contacts, one of the emitter-base junctions is forward biased and injects electrons into the base, while the other junction is reverse biased and small controlling current flows by interband tunneling. Because of emitter contact symmetry, the device possesses exclusive or functionality. Our first devices provided current gain of ~400 at room temperature, at an operating voltage of ~2 V. Here we present an improved version that operates at 1 V, as well as a multiemitter HBT fabrication sequence that is not only fully compatible with a VLSI BiCMOS process, but even saves several processing steps comapred to a standard HBT.
ROOM-TEMPERATURE SINGLE ELECTRON DEVICES BY SCANNING PROBE PROCESS
Authors: MATSUMOTO KAZUHIKO
Published: April 2003

A single electron transistor (SET) and a single electron memory were fabricated using the improved pulse-mode AFM nano-oxidation process. A single electron transistor which works as an electrometer for detecting the potential of the memory node of the single electron memory showed clear Coulomb oscillation characteristics with the period of 2.1 V at room temperature. A single electron memory exhibited a hysteresis loop as the memory bias was scanned from 0 to 10 V and then back down to 0 V.
<111>-ORIENTED GaAs/AlGaAs AND InGaAs/GaAs QUANTUM WELL STRUCTURES FABRICATED BY MOVPE AND THEIR OPTICAL AND STRAIN-INDUCED PIEZOELECTRIC PROPERTIES
Authors: CHO SOOHAENG , SANZ-HERVÁS A. , KIM JONGSEOK , MAJERFELD A. , KIM B. W.
Published: April 2003

We report our recent results on the growth and properties of GaAs/AlGaAs and strained InGaAs/GaAs quantum well (QW) structures grown on (111)A GaAs substrates by atmospheric-pressure metalorganic vapor phase epitaxy. We have fabricated 25-period GaAs/AlGaAs multiquantum well structures with good crystal quality, high photoluminescence (PL) emission intensity and monolayer (ML) well width fluctuation. We also present the optical and piezoelectric properties of strained InGaAs/GaAs single quantum well structures grown on (111)A GaAs. Photoreflectance spectroscopy has been performed to analyze not only the excitonic transitions, but also the Franz-Keldysh oscillations to obtain the electric fields in the well and barriers, which are necessary to determine the actual QW potential profile and, thereby, to properly interpret the properties of the structures. A PL linewidth of 9.7 meV has been also achieved, which corresponds to a 1 ML interfacial roughness for an In0.14Ga0.86As well with a 40 Å width.
ELECTRON DRIFT VELOCITY OF THE TWO-DIMENSIONAL ELECTRON GAS IN COMPOUND SEMICONDUCTORS
Authors: DMITRIEV ALEXANDER , KACHOROVSKI VALENTIN , S. SHUR MICHAEL , STROSCIO MICHAEL
Published: April 2003

We show that, as a consequence of an enhanced electron runaway for two-dimensional (2D) electrons, the peak electron drift velocity and peak electric field in compound semiconductors are smaller than in bulk semiconductors. This prediction agrees with the results of Monte-Carlo simulations for the 2D electrons at a GaAs/GaAlAs heterointerface and with the measured peak velocities in InGaAs/InAlAs quantum wells.
FRONTIERS IN ELECTRONIC NOISE: FROM SUBMICRON TO NANO STRUCTURES
Authors: REGGIANI L. , PENETTA C. , TREFÁN GY. , VAISSIERE J. C. , VARANI L. , GRUZHINSKIS V. , REKLAITIS A. , SHIKTOROV P. , STARIKOV E. , GONZALES T. , MATEOS J. , PARDO D. , BULASHENKO O. M.
Published: April 2003

We survey recent results on electronic noise in nanostructured devices. Three kinds of excess noise referring to hot-carriers in submicron n+nn+ diodes, shot noise in mesoscopic structures, resistance fluctuations in thin film conductors, are considered. The influence of down-sizing on fluctuations is illustrated in each case.
FACTORS LIMITING THE MAXIMUM OPERATING VOLTAGE OF MICROWAVE DEVICES
Authors: ZANONI ENRICO , MENEGHESSO GAUDENZIO , DI CARLO ALDO , LUGLI PAOLO , ROSSI LORENZO
Published: April 2003

The operating voltage of advanced microwave devices is currently limited by impact-ionization and breakdown effects. An extended study of the effects of hot carriers on the breakdown behavior and reliability of GaAs-based and InP-based HEMTs (high electron mobility transistors) has been carried out by means of pulsed measurements, electroluminescence spectroscopy and microscopy and Monte Carlo simulations. We show that the parasitic bipolar effect, which explains kink effects in HEMTs, can also induce regenerative phenomena eventually leading to on-state breakdown. Results concerning the effects of hot carrier aging on GaAs-based and InP-based HEMTs are summarized.
WHY CAN SMART CUT® CHANGE THE FUTURE OF MICROELECTRONICS?
Authors: AUBERTON-HERVÉ A. J. , BRUEL MICHEL
Published: April 2003

Deposition techniques like chemical vapor deposition (CVD) offer to the semiconductor industry the initial flexibility to deposit thin films of key materials on many kinds of substrates. The homoepitaxy or hetroepitaxy techniques using CVD or molecular beam epitaxy (MBE) add the flexibility to get a pure monocrystalline thin film but with a major limitation: the starting substrate has to be monocrystalline. The missing technology has always been the one which allows the growth of a thin monocrystalline film on any kind of substrate. Hydrogen induced splitting (known today as Smart Cut®), discovered at the LETI laboratory in 1991, provides a unique opportunity to get crystalline layers on any kind of substrate. Therefore, a new tool is offered to the semiconductor industry, for new material developments and new structures. This technique is in use in production today on a first application: silicon-on-insulator (SOI) wafers which consist of a monocrystalline film of silicon on a thin amorphous silicon dioxide layer, on top of a silicon wafer. We will discuss the SOI application of the Smart Cut® technology and present other recently demonstrated breakthroughs in new material development, including SiC, compound semiconductor or 3D structures.
ADVANCED SENSORS AND MICROSYSTEMS ON SOI
Authors: MOKWA WILFRIED
Published: April 2003

In the recent decade microsystem technologies (MST) have become a very important field. A lot of miniaturized sensors and microsystems based on silicon technologies have been developed and are in production now. Airbag control for example is mostly based on silicon acceleration sensors. Besides the existing products new products are emerging like drug delivery systems, labs on chip for DNA-analysis or electronic noses. Using SOI new sensor and actuator concepts have become possible. Dielectric insulation offers new possibilities concerning mechanical, thermal or electrical behavior. Microsensors for high temperature application including CMOS electronics are under development. This paper concentrates on SOI with silicon dioxide as insulating material. It will give examples of sensing and actuating devices based on SIMOX and on bonded wafer technology. In addition an example of a more complex microsystem, a retina implant system, will be given.
OPTIMIZED DESIGN OF THE SUBBAND STRUCTURE IN MOS INVERSION LAYERS FOR REALIZING HIGH PERFORMANCE AND LOW POWER Si MOSFETS
Authors: TAKAGI SHIN-ICHI
Published: April 2003

Enhancement of inversion-layer mobility becomes more important in scaled CMOS from the viewpoints of both higher performance and lower power consumption. The severe influence of inversion-layer capacitance prevents MOSFETs with ultra-thin gate oxides from operating at low supply voltage. This paper presents an engineering scenario of the subband structure in the inversion layer for the enhancement of electron mobility in n-MOSFETs. A key factor is to enlarge the difference in the subband energies of the two-fold and four-fold valleys and, as a result, the electron occupancy of the two-fold valleys. The electrical characteristics of two device structures based on this engineering, strained-Si MOSFETs and SOI MOSFETs with SOI films thinner than the inversion layer of bulk MOSFETs, are shown mainly through theoretical calculations. Advantages and disadvantages of these devices are addressed and the possibility of an alternative device structure, which can overcome the drawbacks, is discussed.
PRESENT STATUS AND FUTURE TRENDS OF THE ASIAN SEMICONDUCTOR INDUSTRY
Authors: CHANG C. Y.
Published: April 2003

The Asian semiconductor industry toward the year 2010 is growing rapidly. The major players are Japan, Korea, Taiwan, China, and Singapore. Among them, Taiwan is the fastest-growing country. Taiwan has a strong demand for ICs because of her No. 1 PC manufacturing capability. Japan is still the leader and the major technology driver. Korea will remain No. 1 in DRAM manufacturing. Taiwan is No. 1 in foundry service. The enterprise infrastructure is vertical disintegrated but corporative, which is dynamic, flexible and quick responsive. China comprises a huge market for ICs and is No. 1 in TV production. Singapore is an excellent bridge among Europe, the U.S. and Asia. Hong Kong has a promising future in software and EDA development business. The rest of Asia has a tremendous opportunity for software development and export processing.
THE DRAM ODYSSEY: FROM KILOBITS TO GIGABYTES AND BEYOND
Authors: LEE HEE-GOOK , LEE KYUNG-HO , YOON KYU-HAN , ROH JAE-SUNG , AHN JIN-HONG
Published: April 2003

The evolution of the DRAM industry and technology over the last three decades is described as the most representative ULSI phenomenon. The business nature will be described and key topics in DRAM specific device and process technology such as MOSFET design, cell capacitor and the refresh characteristics will be discussed. The future of this important commodity business will be projected.
TO FILL THE GAP BETWEEN SI-ULSI AND NANODEVICES
Authors: HIRAMOTO TOSHIRO
Published: April 2003

A gap between silicon ULSI and nanodevices and a measure to fill the gap are described. It is shown that there are three phases in the development of silicon nanodevices. In the first phase where we are now, the quantum and single electron charging effects are just troublesome phenomena for ULSI. The most critical and important phase is the second phase, in which new physical phenomena are positively utilized in ULSI and nanodevices are merged into ULSI. The third phase will be the realization of silicon nanodevices that fully utilize the quantum and single electron charging effects. Some examples of favorable quantum and single electron effects that would break the miniaturization limitation of ULSI are reviewed.
INNOVATIVE INTEGRATION BASED ON SILICON-CORE TECHNOLOGIES FOR SENSOR AND COMMUNICATIONS APPLICATIONS
Authors: NAGATSUMA TADAO , MACHIDA KATSUYUKI , ISHII HIROMU , SAHRI NABIL , SHINAGAWA MITSURU , KYURAGI HAKARU , YAMADA JUNZO
Published: April 2003

This paper describes an innovative system integration scheme wherein heterogeneous materials and devices, including photonic devices as well as electronics, are organically integrated on silicon-core circuitry to achieve better performance, higher functionality and lower cost. First, some general integration technology trends in semiconductor electronics are described. Then, after a discussion of new heterogeneous integration schemes based on silicon-core technologies, recent attempts and applications are shown such as low power LSIs, sensors and micromachine switches on silicon and milimeter-wave photonics.
ULTIMATE MOSFETs ON SOI: ULTRA THIN, SINGLE GATE, DOUBLE GATE, OR GROUND PLANE
Authors: CRISTOLOVEANU S. , ERNST T. , MUNTEANU D. , OUISSE T.
Published: April 2003

We tentatively present possible architectures of Silicon On Insulator (SOI) transistors for the final stages of the scaling of silicon microelectronics. The scaling trends for conventional partially depleted and fully depleted SOI MOSFETs are critically examined. A ground plane can considerably attenuate short-channel effects. The manufacturability of extremely thin MOSFETs is demonstrated. Based on quantum calculations, we discuss the merits of double-gate transistors with volume inversion.
STRADDLE-GATE TRANSISTOR: A MOSFET IN THE LIMIT OF USEFUL FIELD-EFFECT
Authors: TIWARI SANDIP , KUMAR A. , WELSER J. J.
Published: April 2003

For transistor, the limit of usable field-effect is defined by tunneling between the source and the drain - the mechanism that competes with field-effect as device dimensions shrink to near deBroglie wavelength. This is a more fundamental constraint in the operation of a field-effect transistor than random dopants, oxide thickness, doping magnitudes and depth, gate resistivity, soft-error rates, etc. We describe here a MOSFET structure, the straddle-gate transistor, that uses inversion regions as virtual source and drain, operates within the limits placed by the other constraints, and operates at acceptable power levels with good power gain and output conductance at 10 nm channel lenth. Experimental behavior of the straddle geometry are also described to summarized the advantages accrued using electron injection from the thin inversion regions.
COOL MULTITHREADING IN HTMT SPELL-1 PROCESSORS
Authors: DOROJEVETS MIKHAIL
Published: April 2003

A COOL-1 multiprocessor shared memory system based on superconductor Rapid Single-Flux Quantum (RSFQ) technology is being developed at SUNY (Stony Brook, USA) within the framework of the Hybrid Technology Multithreaded architecture (HTMT) petaflops project led by JPL. This paper describes a multithreading approach proposed in the COOL-I architecture and mechanisms to exploit the thread level parallelism in RSFQ processors called SPELL-1. Up to 128 fine-grain threads called (instruction) streams arranged in 16 groups of 8 streams each can run in parallel within a SPELL-1 processor. All eight streams comprising each COOL stream cluster can communicate and synchronize directly via shared registers. Fast creation and termination of streams including speculative stream execution are also supported.
ROLE OF DISLOCATIONS IN InGaN-BASED LEDs AND LASER DIODES
Authors: NAKAMURA SHUJI
Published: April 2003

UV InGaN and GaN single-quantum-well structure light-emitting diodes (LEDs) were grown on epitaxially laterally overgrown (ELOG) and sapphire substrates. When the emission wavelength of UV InGaN LEDs was shorter than 380 nm, the external quantum efficiency (EQE) of the LED on ELOG was much higher than that on sapphire only at high-current operation. At low-current operation, both LEDs had the same EQE. When the active layer was GaN, EQE of the LED on sapphire was much lower than that on ELOG at both low- and high-current operation due to the lack of localized energy states formed by In composition fluctuations. In order to improve the lifetime of laser diodes (LDs), ELOG had to be used because the operating current density of the LDs is much higher than that of LEDs. A violet InGaN multi-quantum-well GaN/AlGaN separate-confinement-heterostructure LD was grown on ELOG on sapphire. The LDs with cleaved mirror facets shows an output power as high as 40 mW under room-temperature continuous-wave (CW) operation. The stable fundamental transverse mode was observed at an output power of up to 40 mW. The estimated lifetime of the LDs at a constant output power of 10 mW was more than 2,000 hours under CW operation at an ambient temperature of 60°C.
DISTRIBUTED BALANCED PHOTODETECTOR FOR RF PHOTONIC APPLICATIONS
Authors: SAIF ISLAM M. , CHAU TAI , ITOH TATSUO , WU MING C. , SIVCO DEBORAH L. , CHO ALFRED Y.
Published: April 2003

A novel velocity-matched distributed balanced photodetector operating at 1.3 and 1.55 μm wavelengths has been proposed and experimentally demonstrated. Distributed absorption and velocity matching of the optical and microwave signals are employed to achieve high saturation photocurrent. The velocity matching between the incident optical wave and the output microwave signal allows the detector length and effective absorption volume to increase without penalizing the bandwidth. A common-mode rejection ratio greater than 27 dB has been achieved over a wide range of photocurrents. More than 24-dB suppression of the relative intensity noise of the laser source and EDFA added noise has been achieved in a broadband RF link experiment. Shot-noise limited performance has been achieved with significant improvements in the signal-to-noise ratio over a wide range of frequencies and phase mismatch of input RF signals. The experimental results indicate that the distributed balanced photodetector will have a major impact on most RF photonic systems with its superior potential of reaching very high power levels.
NOVEL MULTIWAVELENGTH MODE-LOCKED SEMICONDUCTOR LASERS: PHYSICS AND APPLICATIONS
Authors: DELFYETT P. J. , MATHASON B. , NITTA I. , SHI H.
Published: April 2003

We develop and study the physics of a novel hybrid wavelength-division-multiplexed, optical timedivision-multiplexed (WDM-OTDM) mode-locked semiconductor laser for applications in ultra-high data rate communication links, computer interconnects, and optical sampling applications. The key philosophy behind using a hybrid approach is that state-of-the-art system performance can be achieved without the necessity of operating at the limits of a either a pure WDM or OTDM technology platform.
MICROCAVITIES, PHOTONIC CRYSTALS AND SEMICONDUCTORS: FROM BASIC PHYSICS TO APPLICATIONS IN LIGHT EMITTERS
Authors: WEISBUCH C. , BENISTY H. , HOUDRÉ R.
Published: April 2003

Photon confined systems in the form of microcavities and photonic crystals overcome the main stumbling block to high efficiency light emitters, i.e. the extraction of photons from high-index materials. On the more fundamental side, they lead to the modification of lifetime for sharp transitions (the Purcell effect), recently observed for quantum dots in micropillars, and to strong light-matter coupling for quantum wells embedded in planar microcavities.
ADVANCED SEMICONDUCTOR LASERS IN THE 3-10 μm WAVELENGTH RANGE
Authors: RAZEGHI MANIJEH
Published: April 2003

Since their first discovery, semiconductor infrared lasers have found many varied applications in the military, communications, medical, and industrial sectors. In this paper, the current status of semiconductor infrared lasers will be reviewed and the advantages and disadvantages of different methods and techniques will be discussed.
HETERODIMENSIONAL CONTACTS AND OPTICAL DETECTORS
Authors: NABET BAHRAM , CASTRO FRANCISCO , ANWAR AMRO , COLA ADRIANO
Published: April 2003

The structures of systems of different dimensions and their interface can be called heterodimensional devices. In this paper we discuss a family of photodetector devices that are based on embedding three dimensional (3D) to two dimensional (2D) contacts by employing modulation doping of a layered heterostructure and contacting the resultant two dimensional electron gas by Schottky metal. The process of current transport between 3D and 2D is analyzed showing barrier enhancement mechanisms due to electron confinement. Optical spectral behavior is also discussed showing the effect of quantized energy levels as well as the electric field present in these multilayer structures.
HIGH FREQUENCY CIRCUITS BASED ON GaAs PHEMT TECHNOLOGY FOR MODERN SENSOR AND COMMUNICATION SYSTEMS
Authors: SCHLECHTWEG M.
Published: April 2003

For sensor and communication system applications, monolithic microwave integrated circuits (MMICs) feature performance, functionality, reliability, and competitive price. In this paper, the potential of PHEMT ICs for communication and sensor applications up to 100 GHz is discussed. Specifically, I will address the application of coplanar waveguide technology for rf ICs, millimeter-wave multifunctional ICs and power amplifiers, as well as mixed-signal ICs and OEICs. A 77-GHz transceiver MMIC designed for automotive collision avoidance radar is presented as an example of a very compact, multifunctional mm-wave chip. A chip set for active and passive imaging at 94 GHz includes low noise and high gain amplifiers, low phase noise oscillators, and phase shifters. An FMCW module is conceived for material characterization. A family of coplanar power amplifier MMICs for wireless communication in the range of 20 to 60 GHz with output powers up to 1 W is presented. Finally, integrated circuits for high-speed data transmission at 40 Gbit/s will be discussed.
A HISTORY OF SURFACE ACOUSTIC WAVE DEVICES
Authors: Morgan David P.
Published: April 2003

This paper gives a historical account of the development of Rayleigh-wave, or surface-acoustic-wave (SAW), devices for applications in electronics. The subject was spurred on initially by the requirements of pulse compression radar, and became a practical reality with the planar interdigital transducer, dating from 1965. The accessibility of the propagation path gave rise to substantial versatility, and a huge variety of devices were developed. Passive SAW devices are now ubiquitous, with applications ranging from professional radar and communications systems to consumer areas such as TV, pagers and mobile phones.

The paper describes the extensive work, particularly in the 1970s, to investigate SAW propagation in crystalline media, including piezoelectric coupling, diffraction and temperature effects. This led to identification of many suitable materials. Concurrently, many devices began development, including pulse compression filters, bandpass filters, resonators, oscillators, convolvers and matched filters for spread spectrum communications. In the 1970s, many of these became established in professional systems, and the SAW bandpass filter became a standard component for domestic TV.

In the 1980s and 90s, SAW responded to the new call for low-loss filters, particularly for mobile phones. With losses as low as 2 dB required (and subsequently achieved) at RF frequencies around 900 MHz, a raft of new technologies was developed. Additionaly, for IF filters special techniques were evolved to reduce the physical size needed for narrow bandwidths. Such devices are now manufactured in very large quantities. In order to satisfy these needs, new types of surface wave, particularly transverse leaky waves, were investigated, and materials using such waves now have their place alongside more traditional materials.
THIN-FILMS FOR SAW DEVICES
Authors: S. HICKERNELL FRED
Published: April 2003

Thin-films play a significant role in surface acoustic wave (SAW) technology. Thin metal films are essential for the generation and detection of SAWs on piezoelectric subtrates, can provide for directional control, influence the velocity and propagation loss, and can be configured to produce a wide variety of time and frequency signal processing functions for electronic systems. Dielectric films have been used to selectively modify the propagation properties of surface waves, protect the surfce, and improve the coupling efficiency and temperature characteristics of SAW devices. Piezoelectric films have extended SAW device developments to amorphous and nonpiezoelectric crystals for enhanced frequency and loss performance, lower cost, and microelectronic integration. Semiconductor, optical, and magnetic films have shown promise for active acoustoelectronic, acoustooptic, and magnetoacoustic devices. Chemically sensitive films are the basis for SAW sensor developments. Active research continues today in improving the properties and utilization of thin films on SAW substrates through advances in processing and characterization.
BULK AND SURFACE ACOUSTIC WAVES IN ANISOTROPIC SOLIDS
Authors: L. ADLER ERIC
Published: April 2003

In this paper methods for analyzing acoustic propagation characteristics for bulk and surface acoustic waves in anisotropic piezoelectric multilayers are described. The methods's conceptual usefulness is demonstrated by examples showing how problems of guided wave propagation in complicated layered surface acoustic wave device geometries are simplified. The formulation reduces the acoustoelectric equations to a first order ordinary matrix differential equation in the variables that must be continuous across interfaces. The solution to these equations is a transmission matrix that maps the variables from one layer face to the other. Interface boundary conditions for a planar multilayer are automatically satisfied by multiplying the individual transmission matrices in the appropriate order thus reducing the problem to imposing boundary conditions appropriate to the remaining free surface. The dimensionality of the problem being independent of the number of layers is a significant advantage. A classification scheme for reducing problem dimensionality, based on an understanding of crystal symmetry properties, further simplifies surface acoustic wave problems.
ANALYSIS OF SAW EXCITATION AND PROPAGATION UNDER PERIODIC METALLIC GRATING STRUCTURES
Authors: HASHIMOTO KEN-YA , OMORI TATSUYA , YAMAGUCHI MASATSUNE
Published: April 2003

This paper reviews numerical techniques used for the analysis of excitation and propagation properties of surface acoustic waves (SAWs) under periodic metallic grating structures. First, the finite element method (FEM), the boundary element method (BEM) and the spectral domain analysis (SDA) are compared for the SAW field analysis. Then it is shown how skillfully excitation and propagation properties are characterized by using the FEM/SDA technique. Extended FEM/SDA theories are also detailed for the analysis of multi-finger grating structures.
HIGH-PERFORMANCE SURFACE TRANSVERSE WAVE RESONATORS IN THE LOWER GHz FREQUENCY RANGE
Authors: AVRAMOV IVAN D.
Published: April 2003

Since the first successful surface transverse wave (STW) resonator was demonstrated by Bagwell and Bray in 1987, STW resonant devices on temperature stable cut orientations of piezoelectric quartz have enjoyed a spectacular development. The tremendous interest in these devices is based on the fact that, compared to the widely used surface acoustic waves (SAW), the STW acoustic mode features some unique properties which makes it very attractive for low-noise microwave oscillator applications in the 1.0 to 3.0 GHz frequency range in which SAW based or dielectric resonator oscillators (DRO) fail to provide satisfactory performance. These STW properties include: high propagation velocity, material Q-values exceeding three times those of SAW and bulk acoustic waves (BAW) on quartz, low propagation loss, unprecedented 1/f device phase noise, extremely high power handling ability, as well as low aging and low vibration sensitivity. This paper reviews the fundamentals of STW propagation in resonant geometries on rotated Y-cuts of quartz and highlights important design aspects necessary for achieving desired STW resonator performance. Different designs of high- and low-Q, low-loss resonant devices and coupled resonator filters (CRF) in the 1.0 to 2.5 GHz range are characterized and discussed. Design details and data on state-of-the-art STW based fixed frequency and voltage controlled oscillators (VCO) with low phase noise and high power efficiency are presented. Finally, several applications of STW devices in GHz range data transmitters, receivers and sensors are described and discussed.
SAW ANTENNA DUPLEXERS FOR MOBILE COMMUNICATION
Authors: HIKITA MITSUTAKA
Published: April 2003

Mobile communications systems such as cellular radios have recently become very widespread and important to both business and personal users. A key component in the radio transceiver is an antenna duplexer, which makes it possible to use a single antenna to transmit and receive RF signals simultaneously. In this chapter, block diagrams of radio transceivers are shown and the frequency characteristics required for duplexers are discussed with regard to the system requirements. Procedures for designing duplexers using SAW-resonator-coupled filters and experimental results relevant to several systems are presented. Non-linear characteristics of the duplexers are also discussed.
LADDER TYPE SAW FILTER AND ITS APPLICATION TO HIGH POWER SAW DEVICES
Authors: SATOH YOSHIO , IKATA OSAMU
Published: April 2003

SAW filters with one-port SAW resonators being connected in a ladder structure, which is called ladder type SAW filter, have many features such as low insertion-loss, wide pass-band and simple filter design and so on. The design methodology, features of characteristics, and developments of higher frequency filter are described for an application in cellular phones. Furthermore, in order to apply to high power SAW devices such as the antenna duplexer of cellular phones, the material of inter-digital transducers (IDT) was improved to have high power durability. The optimum design in a ladder type SAW filter, the improvement in materials for IDT, and the optimum design of the package, all contributed the success of realizing a small SAW antenna duplexer.
COUPLING-OF-MODES ANALYSIS OF SAW DEVICES
Authors: PLESSKY VICTOR , KOSKELA JULIUS
Published: April 2003

The coupling-of-modes approach for modeling and analyzing surface-acoustic wave devices is reviewed. We discuss the established formalism and survey the modifications introduced to account for phenomena such as resistivity, dispersion and in particular, the effects related to surface transverse wave and leaky surface-acoustic wave devices. The extraction of the COM parameters from experiments and theoretical simulations are considered. The design of various SAW devices such as resonators and resonator filters as well as practical aspects are discussed. Finally, the unresolved modeling problems are addressed.
NEW PIEZOELECTRIC SUBSTRATES FOR SAW DEVICES
Authors: KOSINSKI JOHN A.
Published: April 2003

Recent developments in single crystal piezoelectric materials have focused on the search for "ideal" materials with zero temperature coefficient of frequency orientations featuring jointly high piezoelectric coupling, high intrinsic Q, zero power flow angle, and minimized diffraction effects. In addition, the desired materials should have no low temperature phase transitions, and a physical chemistry conducive to repeatable, low cost growth and wafer scale device production. As difficult as it might seem to find such "ideal" materials, three completely different but strong candidate materials have emerged recently: the quartz homeotype gallium orthophosphate, the quartz isotype calcium gallo-germanates (langasite, langanite, langatate, etc.), and diomignite (lithium tetraborate). The current state-of-the-art and prospects for future development of these materials are considered.
SAW DEVICE BEYOND 5 GHz
Authors: ODAGAWA HIROYUKI , YAMANOUCHI KAZUHIKO
Published: April 2003

Here we describe recent high frequency SAW technology based on ultra-fine fabrication techniques using electron beam (EB) exposure direct writing and low-loss wide-band filter applications beyond 5 GHz. We especially consider the propagation property of SAWs in the 10 GHz range, which is important for low-loss characteristics, the fabrication technology, and some examples of low-loss filters using unidirectional transducers and ladder type SAW filters.
WIRELESS SAW IDENTIFICATION AND SENSOR SYSTEMS
Authors: SCHMIDT F. , SCHOLL G.
Published: April 2003

Identification and sensor systems based on surface acoustic waves exhibit intriguing properties which have hitherto remained unexploited by semiconductor-based systems. They offer a long readout distance of up to more than 20 meters with purely passive surface acoustic wave (SAW) devices. SAW devices operate with no battery or wiring, withstand extreme temperatures and work reliably and maintenance-free over many decades even in harsh industrial environments. Because they operate at frequencies in the GHz range, SAW identification and sensor systems are well protected from the electromagnetic interference that often occurs in the vicinity of industrial equipment such as motors and high-voltage lines. The fundamentals and design rules of numerous passive wireless SAW sensor and identification systems for industrial and domestic applications as well as relevant practical work will be presented.
INTERACTION OF SURFACE ACOUSTIC WAVES, ELECTRONS, AND LIGHT
Authors: WIXFORTH ACHIM
Published: April 2003

The interaction of surface acoustic waves with free carriers in semiconductor nanostructures has turned out to yield a powerful tool not only for the investigation of the dynamic conductivity of such quantum systems. The latter has been shown in the study of the dynamics of the fractional and integer quantum Hall effect and many other interesting physical phenomena. The interaction is based on a relaxation type and impedance matching effect. However - to make practical use of this strong interaction, the electromechanical coupling coefficients of state-of-the-art semiconductor layered systems are too small. A hybrid technique, merging the strong piezoelectricity of LiNbO 3 or similar substrates with the excellent electronic properties of band gap engineered semiconductor quantum wells tackles this problem. Based on this new hybridization technique, several acoustoelectric high frequency devices have been realized. But also optically generated free electrons and holes in a semiconductor efficiently interact with the piezoelectric fields and potentials accompanying the surface wave. Those are able to field-ionize optically generated excitons leading to an acoustically induced quenching of the photoluminescence of a semiconductor quantum well, and to a system in which photonic signals can be efficiently converted into spatially separated electrons and holes which then can be transported over macroscopic distances along the quantum well. Finally - at a predetermined time and location on the sample – they can be reassembled into photonic signals. But also much simpler photonic devices can be realized using surface acoustic waves on semiconductor samples. For instance, we report on a simple, yet efficient camera type of device for pattern recognition and image processing.
HIGH-PERFORMANCE Si and SiGe BIPOLAR TECHNOLOGIES AND CIRCUITS
Authors: WURZER MARTIN , MEISTER THOMAS F. , BÖCK JOSEF , SCHÄFER HERBERT , AUFINGER KLAUS , BOGUTH SABINE , KNAPP HERBERT , REST MIRJANA , SCHREITER RENATE , TREITINGER LUDWIG
Published: April 2003

In this paper we present Si and SiGe bipolar technologies and circuits suited for present and future high-performance communication systems. The silicon bipolar technology described has an implanted base and, without increase in process complexity in comparison to current production technologies, transit frequencies of 52 GHz and maximum oscillation frequencies of 65 GHz are achieved. The transistors of the described epitaxial SiGe-base technologies exhibit transit frequencies of 81 GHz and maximum oscillation frequencies of 95 GHz. Measurement results of circuits realized in these technologies for low power and high-speed applications are presented: a 43 GHz low power dynamic frequency divider, a 23 GHz monolithically integrated oscillator, a 40 Gb/s clock and data (CDR) recovery realized in the pure silicon bipolar technology, and a 53 GHz static frequency divider, a 79 GHz dynamic frequency divider and a 20 GHz/27 mW dual-modulus prescaler in the SiGe technology.
SELF-ALIGNED Si BJT/SiGe HBT TECHNOLOGY AND ITS APPLICATION TO HIGH-SPEED CIRCUITS
Authors: WASHIO KATSUYOSHI
Published: April 2003

In a Si bipolar transistor (BJT) and a SiGe heterojunction bipolar transistor (HBT), self-aligned structures help to improve high-speed and high-frequency characteristics. These structures are used to reduce parasitic capacitance and resistance, and thus maximize the transistor's intrinsic performance. In addition to generally used process technology, selective metal deposition to form electrodes and selective epitaxial growth of Si/SiGe multilayers are applied in the fabrication process. To improve the intrinsic speed, the cutoff frequency, a shallow diffusion process for Si BJTs and a graded-Ge profile SiGe-base layer for SiGe HBTs are used. These also enable a high maximum oscillation frequency and a small gate delay in the emitter-coupled logic through the synergistic effect of the self-aligned structure. Both high-speed digital circuits — frequency dividers up to millimeter-wave bands and a multiplexer/demultiplexer for optical-fiber-links — and high-frequency analog circuits for optical-fiber-links — a preamplifier, an automatic gain control amplifier. a limiting amplifier, and a decision circuit — have been implemented by applying the self-aligned Si BJTs and/or SiGe HBTs.
SMALL-SCALE InGaP/GaAs HETEROJUNCTION BIPOLAR TRANSISTORS FOR HIGH-SPEED AND LOW-POWER INTEGRATED-CIRCUIT APPLICATIONS
Authors: OKA TOHRU , HIRATA KOJI , SUZUKI HIDEYUKI , OUCHI KIYOSHI , UCHIYAMA HIROYUKI , TANIGUCHI TAKAFUMI , MOCHIZUKI KAZUHIRO , NAKAMURA TOHRU
Published: April 2003

Small-scale InGaP/GaAs heterojunction bipolar transistors (HBTs) with high-speed as well as low-current operation are demonstrated. To reduce the emitter size SE and the base-collector capacitance CBC simultaneously, the HBTs are fabricated by using WSi/Ti as the base electrode and by burying SiO 2 in the extrinsic collector region. WSi/Ti metals simplify and facilitate processing to fabricate small base electrodes, and the buried SiO 2 reduces the parasitic CBC under the base electrode. The cutoff frequency fT of 156 GHz and the maximum oscillation frequency f max of 255 GHz were obtained at a collector current Ic of 3.5 mA for the HBT with SE of 0.5 μ m ×4.5 μ m , and fT of 114 GHz and f max of 230 GHz were obtained at IC of 0.9 mA for the HBT with SE of 0.25 μ m ×1.5 μ m . A 1/8 static frequency divider operated at a maximum toggle frequency of 39.5 GHz with a power consumption per flip-flop of 190 mW. A transimpedance amplifier provides a gain of 46.5 dB·Ω with a bandwidth of 41.6 GHz at a power consumption of 150 mW. These results indicate the great potential of our HBTs for high-speed. low power integrated circuit applications.
PROSPECTS OF InP-BASED IC TECHNOLOGIES FOR 100-GBIT/S-CLASS LIGHTWAVE COMMUNICATIONS SYSTEMS
Authors: ENOKI TAKATOMO , SANO EIICHI , ISHIBASHI TADAO
Published: April 2003

This paper describes the device technologies that will be instrumental in achieving 100-Gbit/s-class ultrahigh-speed lightwave communications systems and clarifies the device technology issues we must address before we can make such systems a reality. At the interface between optical and electrical units, their monolithic integration is necessary and a uni-traveling carrier photodiode (UTC-PD) enables us to simplify the interface circuits. In high-speed circuits, InP-based HEMT's and HBT's will still be key devices. Further scaling down of HEMT's and reduction of their parasitic capacitance are the major subjects to achieve 100 Gbit/s operations. For HBT's, reduction of the product of feedback capacitance and base resistance are necessary. Estimations of operation speed for basic circuits in lightwave communications systems are summarized to set targets for designing device structures.
SCALING OF InGaAs/InAlAsHBTs FOR HIGH SPEED MIXED-SIGNAL AND mm-WAVE ICs
Authors: RODWELL M. J. W. , URTEAGA M. , BETSER Y. , MATHEW T. , KRISHNAN P. , SCOTT D. , JAGANATHAN S. , MENSA D. , GUTHRIE J. , PULLELA R. , LEE Q. , AGARWAL B. , BHATTACHARYA U. , LONG S. , MARTIN S. C. , SMITH R. P.
Published: April 2003

High bandwidths are obtained with heterojunction bipolar transistors by thinning the base and collector layers, increasing emitter current density, decreasing emitter contact resistivity, and reducing the emitter and collector junction widths. In mesa HBTs, minimum dimensions required for the base contact impose a minimum width for the collector junction, frustrating device scaling. Narrow collector junctions can be obtained by using substrate transfer processes, or -if contact resistivity is greatly reduced -by reducing the width of the base Ohmic contacts in a mesa structure. HBTs with submicron collector junctions exhibit extremely high f max and high gains in mm-wave ICs. Logic gate delays are primarily set by depletion-layer charging times, and neither fτ nor f max is indicative of logic speed. For high speed logic, epitaxial layers must be thinned, emitter and collector junction widths reduced, current density increased, and emitter parasitic resistance decreased. Transferred-substrate HBTs have obtained 21 dB unilateral power gain at 100 GHz. If extrapolated at -20 dB/decade, the power gain cutoff frequency f max is 1.1 THz. Transferred-substrate HBTs have obtained 295 GHz f τ . Demonstrated ICs include lumped and distributed amplifiers with bandwidths to 85 GHz, 66 GHz master-slave flip-flops, and 18 GHz clock rate Δ-Σ ADCs.
RSFQ TECHNOLOGY: PHYSICS AND DEVICES
Authors: BUNYK PAUL , LIKHAREV KONSTANTIN , ZINOVIEV DMITRY
Published: April 2003

Rapid Single-Flux-Quantum (RSFQ) logic, based on the representation of digital bits by single quanta of magnetic flux in superconducting loops, may combine several-hundred-GHz speed with extremely low power dissipation (close to 10-18 Joule/bit) and very simple fabrication technology. The drawbacks of this technology include the necessity of deep (liquid-helium-level) cooling of RSFQ circuits and the rudimentary level of the currently available fabrication and testing facilities. The objective of this paper is to review RSFQ device physics and also discuss in brief the prospects of future development of this technology in the light of the tradeoff between its advantages and handicaps.
RSFQ TECHNOLOGY: CIRCUITS AND SYSTEMS
Authors: BROCK DARREN K.
Published: April 2003

Rapid Single-Flux-Quantum (RSFQ) logic is a superconductor IC technology that, with only a modest number of researchers worldwide, has produced some of the world's highest performance digital and mixed-signal circuits. This achievement is due, in part, to a constellation of characteristics that manifest themselves at the circuit level – namely, high-speed digital logic at low-power, ideal interconnects, quantum accuracy, scalability, and simplicity of fabrication. A necessary key to translating these advantages to the system-level involves understanding the I/O, synchronization, and packaging issues associated with a cryogenic technology. The objective of this paper is to review the status of current RSFQ circuit-level infrastructure components and their potential impact on system-level applications.
QUANTUM TRANSPORT IN SEMICONDUCTOR DEVICES
Authors: FERRY D. K. , VASILESKA D. , GRUBIN H. L.
Published: April 2003

It is clear that continued scaling of semiconductor devices will bring us to a regime in which device gate lengths are less than 50 nm within another decade. Pushing to dimensional sizes such as this will probe the transition from classical to quantum transport, and there is no present approach to the quantum regime that has proved effective. Contrary to the classical case in which electrons are negligibly small, the finite extent of the momentum space available to the electron sets size limitations on the minimum wave packet—this is of the order of a few nanometers. While quantum transport formalism has been applied to a variety of problems, in most cases it has not been overly successful. In this paper, we discuss the problems and some of the approximate approaches which will ease the above-mentioned transition.
QUANTUM TRANSPORT AND ITS SIMULATION WITH THE WIGNER-FUNCTION APPROACH
Authors: JACOBONI CARLO , BRUNETTI ROSSELLA , BORDONE PAOLO , BERTONI ANDREA
Published: April 2003

In this paper a review of the research performed in recent years by the group of the authors is presented. The definition and basic properties of the Wigner function are first given. Several forms of its dynamical equation are then derived with the inclusion of potential and phonon scattering. For the case of a potential V(r) the effect of the classical force, for any form of V(r), is separated from quantum effects due to rapidly varying potentials. An elaboration of the dynamical equation is introduced that leads to Wigner paths formed by free flights and scattering events. These are especially suitable for a Monte Carlo solution of the transport equation for the Wigner function very similar to the semiclassical traditional Monte carlo simulation. The Monte Carlo simulation can be extended also to the momentum and frequency dependent Wigner function based on a two-time Green function. Several numerical results are presented throuhout the paper.
BLOCH DYNAMICS IN SPATIALLY LOCAL INHOMOGENEOUS ELECTRIC FIELDS
Authors: REYNOLDS JOSEPH P. , IAFRATE GERALD J. , HE JUN
Published: April 2003

The influence of local inhomogeneities on the electric field dependent properties of Bloch electrons is studied. The homogeneous electric field is described through the use of the vector potential, and the instantaneous Wannier functions of the homogeneous field dependent Hamiltonian are used as bases states to depict Bloch dynamics and properties. Model examples are treated using Slater-Koster inhomogeneities and nearest-neighbor tight-binding band structure in a one dimensional, single-band analysis. Detailed analysis is presented for the special case of a constant electric field; here the influence of localization due to the presence of the electric field is shown to clearly affect the energy spectrum of the Bloch electron for a single and double impurity configuration.