Characterization of silicon devices incorporating the capacitor which uses ferroelectric thin films as capacitor dielectrics is presented. As cases in point, a DRAM cell capacitor and an analog/digital silicon IC using the thin film of barium strontium titanate (Ba1-xSRxTiO3) are examined. Production and characterization of the ferroelectric thin films are also described, focusing on a Metal Organic Deposition technique and liquid source CVD.

In order to construct a high-capacity and high-reliable indoor wireless communications system, it is essential to design the modulation/demodulation, coding and access schemes with high and variable data rate transmission capabilities, which meet the technical requirements inherent to wireless communications, i.e., high frequency utilization efficiency and robustness for fading. In this paper, we propose the frequency and time division multiple access with demand-assignment (FTDMA/DA) using multicarrier modulation as a frequency and time synchronous answer to meet the requirements, and analyze the performance of the FTDMA/DA system, taking account of teletraffic characteristics of multimedia information sources.

This paper describes a future private network service and the system configurations for providing it. Technologies and service trends in local area and wide area networks are shown. As network services become more diversified and integrated, it becomes more difficult for users to use the networks effectively. This paper shows how this problem can be solved by using virtual network technology to attain seamless networking. It also presents the concept of group networking among many parties, which can be used as the basis for a virtual private network.

This paper presents a view on coming photonic network in which machines are potential customer to the network. The network will be providing unlimited number of virtual free spaces in which point to point and broadcasting modes of information interchanges are taking place simultaneously. It is also pointed out that the Asynchronous Transfer Mode (ATM) should be evolved to support this type of network by using true photonic switching technology.

A photonic inter-module connector for near-future electronic switching systems is demonstrated through the use of silica-based 88 optical switches. A small-scale switch matrix is sufficient because the near-future systems will consist of a limited number of modules. If an active module is affected by a fatal fault or accident, a stand-by module must quickly take its place. The experimental photonic inter-module connector can switch 156-Mbit/s photonic interconnections between seven subscriber-line-concentrator modules and eight circuit-switching modules.

This paper describes a segment driver IC for high-quality liquid-crystal-displays (LCDs). Major design issues in the segment driver IC are a wide signal bandwidth and excessive output-offset variation both within a chip and between chips. After clarifying the trade-off relation between the signal bandwidth and the output-offset variation originated from conventional sample-and-hold (S/H) circuits, two wide-band S/H circuits with low output-offset variation have been introduced. The basic ideas for the proposed S/H circuits are to improve timing of the sampling pulses applied to MOS analog switches and to prevent channel charge injection onto a storage capacitor when the switches turn off. The inter-chip offset-cancellation technique has been also introduced by using an additional S/H circuit. Two test chips were implemented using the above S/H circuits for demonstration purposes. The intra-chip output-offset standard deviation of 9.5 mVrms with a 3dB bandwidth of 50 MHz was achieved. The inter-chip output-offset standard deviation was reduced to 5.1 mVrms by using the inter-chip offset-cancellation technique. The evaluation of picture quality of an LCD using the chips shows the applicability of the proposed approaches to displays used for multimedia applications.

Two types of novel nVT level shift circuits based on the square law characteristics of MOSFETs have been proposed. These circuits generate VIN+nVT or VIN-nVT (where VT is a threshold voltage), if the input voltage is applied as the VIN. These circuits can be widely used in MOSFET characterization, compensating VT effect, VT measurement, level shifting, etc. Type 1 is directly derived from the nVT-sift circuit proposed by Wang. Type 2 can reduce a total chip area than type 1 and has a wider input range. SPICE simulations show that the proposed circuits have a very wide input range and a small power consumption.

The modular and growable photonic ATM switch architecture described in this paper uses both time-division and wavelength-division multiplexing technologies, so the switch capacity can be expanded in both the time and frequency domains. It uses a new implementation of output buffering scheme that overcomes the bottleneck in receiving and storing concurrent ultra fast optical cells. The capacity in one stage of a switch with this architecture can be increased from 32 gigabits per second to several terabits per second in a modular fashion. The proposed switch structure with output channel grouping can greatly reduce the amount of hardware and still guarantee the cell sequence.

Among various photonic switching technologies, photonic frequency division multiplexing technology is most promising. In this paper a novel photonic FDM (Frequency Division Multiplexing) system is proposed. The proposed system consists of n (multiplicity of frequencies) independent subnetworks, each of which is identified by a specific frequency, and of which each network topology is identical. When a connection is required by a terminal, the network selects a subnetwork that can afford it, and assigns a frequency representing the selected subnetwork to the terminal. This system eliminates frequency converting devices and traffic concentration equipment, which will reduce the size and cost of the system. A very small sized switching system of very large capacity will be easily realized. In this paper, first we will address the basic concept of the proposed system, and then discuss some technical problems and their solutions concerning network configuration, switch matrix structure, subscriber network configuration, control scheme and frequency multiplicity. Some experimental results are also mentioned.

The first demonstration of 88 optical switch matrix with low drive voltage digital optical switch elements is reported. A polarization-independent 88 digital optical switch with drive voltage of 40V at 1.3µm wavelength can be realized by assigning proper lengths for switch elements. The average insertion loss of 10dB and polarization independent switching with average crosstalk of -16dB (limited by the middle stage 22 switch) are achieved.

An HDTV still-picture camera that uses four PAL CCD sensors has been developed for use as a high-speed, high-resolution image reader. The CCD sensors are optically coupled to a single lens by a pyramidal mirror. Each CCD sensor reads a quarter of the image and the four quarter-images are combined into one HDTV picture. Discontinuities at the lines where the four images join can be eliminated by white- and dark-level correction and gamma correction. Moreover, smoothing processing using a weighted-mean method is performed to produce a seamless picture. With this processing the camera can consistently produce seamless pictures.

The increasing size and complexity of integrated circuits has lead to the development of advanced algorithms and techniques for circuit simulation. The majority of circuit simulators rely on the Newton-Raphson algorithm for the solution of nonlinear equations that arise from the circuit description. Unfortunately, a good estimate of the root to be found is needed for the algorithm to converge. The convergence rate of the algorithm is quadratic once the method gets "close enough" to the solution, but before reaching this point the method may follow a complex route through unrealistic values of the circuit variables, leading eventually to divergence. Simulations performed with SPICE on several test circuits reveal that during the first iterations of the Newton-Raphson algorithm internal node voltages exceed the power supply voltage of several orders of magnitudes even for simple circuits. A new simulation program called MUSIC (Multilevel Simulator for Integrated Circuits) has been developed to overcome these drawbacks. In MUSIC the circuit to be simulated is decomposed in subcircuits, which may contain instances of other subcircuits up to any nesting level. Subcircuits are then simulated independently with a multilevel Newton algorithm permitting to reduce both the large oscillations that circuit variables undergo during the simulation process and the number of iterations necessary for the circuit to converge. The novel feature of this multilevel algorithm is the propagation of the already calculated terminal voltages, which become known after a subcircuit has converged, to the subcircuits connected to same terminals. In this way the information regarding node voltages is propagated through the network without constraining conditions that do not have physical counterpart. Simulations performed on chains of inverters and a 4-bit full adder evidence how MUSIC is able to improve the convergence rate and to reduce the intermediate voltage spikes.

An eye-contact technique using a blazed half-transparent mirror (BHM) is developed. This half-transparent mirror (HM) consists of an in-line array of many slanting micro-HMs. We fabricated a prototype system and confirmed the principle of this technique. The resolution of an image reflected by a BHM was simulated to determine how to improve the image quality and the factors degrading the resolution were clarified.

Tunneling generation becomes increasingly important in modern devices both as a source of leakage and for special applications. Mostly, the observed phenomena are attributed to band-to-band tunneling, although from early investigations of Esaki diodes it is well known that at lower field strengths trap-assisted tunneling is responsible for non-ideal IV-characteristics. In this paper we apply microscopic models of trap-assisted and band-to-band tunneling, which were derived from first-principle quantum-mechanical calculations, in a general multi-device simulator. Special simplified versions of the models were developed for the purpose of fast numerical computations. We investigate pn-junctions with different doping profiles to reveal the relative contribution of the two tunneling mechanisms. Simulated currents as function of voltage and temperature are presented for each individual process varying the basic physical parameters. It turns out that the slope of reverse IV-characteristics dominated by trap-assisted tunneling is similar to those which are determined by band-to-band tunneling, if the localized state of the recombination center is only weakly coupled to the lattice. In the model such a slope is produced by field-enhancement factors of the Shockley-Read-Hall lifetimes expressing the probability of tunneling into (or out of) excited states of the electron-phonon system. The temperature dependence of these field-enhancement factors compensates to a certain extent the expected strong temperature effect of the Shockley-Read-Hall process. The latter remains larger than the temperature variation of phonon-assisted band-to-band tunneling, but not as much as often stated. Consequently, the slope of the IV-characteristics and their temperature dependence are not the strong criteria to distinguish between trap-assisted and band-to-band tunneling. The origin of tunnel currents in silicon rather depends on the sum of physical conditions: junction gradient, nature and concentration of defects, temperature and voltage range.

A new kind of optical local area network (LAN), using a demand assign wavelength division multiple access (DA-WDMA) scheme, has been proposed. The proposed LAN consists of two parts; an ordinary standardized LAN and an overlaid network using wavelength division (WD) channels. The proposed network can provide bit-rate independent communication channels on the ordinary LAN without limiting the capacities for the other channels. It also exhibits upgrade possibilities from present standardized networks. An access controller, which consists of software in addition to the ordinary LAN controller, a digital signal processor (DSP) etc., was developed for DA-WDMA control. The network node operation has been demonstrated using guided-wave acousto-optic (AO) mode converters as a tunable wavelength add-drop multiplexer (ADM).

The photonic Space-Division (SD) switching network is attractive for constructing flexible broadband networks. This paper first describes possible applications of the network. A broadband STM switching system, Digital Cross-connect System (DCS) and Video signal distribution switch, especially for HDTV signals, are attractive near term applications. Recent activities on photonic SD switching network developments aiming at these application are also reviewed. A 128 line prototype switching system has been developed. This system utilizes LiNbO3 photonic switch matrices, semiconductor traveling wave amplifiers (TWAs) and three dimensional optical interconnections for multi stage switching networks. It is confirmed that the system has been operating in providing 150Mb/s TV phone services and 600Mb/s HDTV distribution services with high stability. An experimental optical Digital Crossconnect System (optical DCS) has also been demonstrated. Line failure restoration operation at 2.4Gb/s has been successfully demonstrated. These experimental demonstrations prove that practical photonic switching systems are feasible with current technologies.

Junction leakage current of trench isolation devices is strongly influenced by trench configuration. The origin of the leakage current is the mechanical stress that is generated by the differential thermal expansion between the Si substrate and the SiO2 filled isolation trench during the isolation forming process. A two-dimensional mechanical stress simulation was used to analyze trench-isolated devices. The simulated distribution and magnitude of stress were found to agree with Raman spectroscopic measurements of actual devices. The stress in the deeper regions between deep trenches is likely to increase greatly as the size of devices diminishes, so it is important to reduce this stress and thus suppress junction leakage current.

This paper describes a new free-space optical switch structure based on cascaded beam shifters (each consists of a liquid-crystal polarization controller array and a birefringent plate). This structure comprises 2-input, 2-output switching elements that are locally connected by links. It is applicable to a variety of switching networks, such as a Clos network. The switching network based on this structure is an analog switch that is transparent to signal format, bit rate, and modulation type, so it can handle various types of optical signals. Theoretical feasibility studies indicate that compact large-scale switches (i.e., 100-1000 ports) with relay lens systems can be implemented using beam shifters with a 0.4-dB insertion loss and a 30-dB extinction ratio. Experimental feasibility studies indicate that a 1024-cell beam shifter module with a 0.5-dB insertion loss and a 23-dB extinction ratio is possible at present. An alignment-free assembly technique using precise alignment guides is also confirmed. An experimental 8-stage, 1024-input 256-output concentrator shows low insertion loss characteristics (6.8dB on average) owing to the low-loss beam shifters and the alignment-free assembly technique. Practical switching networks mainly require the improvement of the extinction ratio of the beam shifter module and the development of a fiber pig-tailing technique. This switch structure is applicable to transparent switching networks such as subscriber line concentrators and inter-module connectors.

The demand for large-capacity photonic switching systems will increase as regular broadband ISDN (B-ISDN) spreads and full-motion video terminals replace telephones. Large-scale and economical optical fiber transmission lines have been built based on time-division (TD) multiplexing. To reduce costs, it is important to increase the channel multiplexity of both transmission and switching systems by using TD and wavelength-division (WD) or frequency-division (FD) technologies. We surveyed photonic switching systems' architecture and switching network structures. Switching can be divided into circuit or synchronous transfer mode (STM) switching, and asynchronous transfer mode (ATM) switching. A variety of photonic STM and ATM switching systems based on the two switching technologies have recently been proposed and demonstrated.

Central switches are expected to operate at the rate of Terabit per second in high speed networks, like the B-ISDN. Photonic switches using lightwave technology based on wavelength division multiplexing (WDM) and frequency division multiplexing (FDM) are promising ones for high speed switching. Such lightwave networks are mainly divided into two groups, according to the number of hops required for packets to arrive at their destinations: single-hop networks such as networks using star coupler and multihop networks such as Manhattan Street Network and ShuffleNet. In this paper we focus our attention on multihop networks and propose a mesh network, referred to as RookNet, for high speed communication. The average transmission delay time and maximum throughput of RookNet is approximately analyzed. It is shown that, as the number of nodes goes to infinity, the maximum throughput aproaches 0.433 and 0.485 when each node is equipped with no internal buffer and internal buffers of infinite capacity for relayed packets, respectively.