Search

In this paper, we investigate the performance of inverters and ring oscillators composed of gate-all-around (GAA) silicon nanowire and nanosheet (NSH) field-effect transistors (FETs), compared with FinFETs, for sub-10nm logic technology applications. Our TCAD transient simulations reveal that ring oscillators with 3 stacked channels with NSH width, three times wider than the fin width, exhibit improvements of up to 22% in the oscillation frequencies. compared to a ring oscillator with FinFETs. Thus, our study provides an insight for device down-selection in the development of GAA FET technology.

A smart grid is an electrical power grid infrastructure for improved efficiency, reliability, and safety based on automated monitoring and control of data and communication. IEC 61850 and IEC 61970 are core standards in the smart grid domain for substation automation and power operation management. Significant data exchange is involved between the IEC 61850 level and the IEC 61970 level. However, due to different perspectives on smart grid and independent evolution, IEC 61850 and IEC 61970 are not compatible. This forces practitioners to come up with their own data mappings between the standards in an ad-hoc manner, which leads to significant issues on interoperability and data consistency. An effective solution for this is to define a common semantic model for both substation automation and operation management. In this paper, we present a metamodeling approach for unifying IEC 61850 and IEC 61970 to provide a common semantic model and demonstrate the approach using a power transformer example.

Role-Based Access Control (RBAC) and Mandatory Access Control (MAC) are widely used access control models. They are often used together in domains where both data integrity and information flow are concerned. There is much work on combined use of RBAC and MAC policies at the kernel level, which focuses on enforcing hybrid policies at run-time. However, there is little work on techniques for developing hybrid systems of RBAC and MAC from a development perspective. In this work, we present a feature-based modeling approach for developing hybrid access control systems. In the approach, RBAC and MAC are designed in terms of features and features are configured based on requirements. Configured features are then composed to produce a design model that supports hybrid access control. The approach enables systematic development of hybrid systems of RBAC and MAC and reduces development complexity and errors through need-based configuration of features in early development phases. We use a hospital system to demonstrate the approach. Tool support for the approach is also discussed.

In the realm of substation automation (SA), communication infrastructure plays a vital role in mediating between physical and virtual worlds of substation. Specification of data exchanges through standardized communication stacks is therefore an important issue for all substation equipment manufacturers seeking to provide vendor interoperability. As communication arena is changing day by day, the need for efficient and reliable communication infrastructure to address SA is evident. In this respect, a communication network constitutes the core of the SA, thus the design of cost-effective and reliable network architecture is a crucial task. Most of the existing communication networks claim to address the need of communication architecture for SA but in some regard these claims just could not fulfill the constraints imposed by highly available environment for SA. This paper presents a survey and analysis of the current state-of-the-art communication infrastructure in the SA and proposes giga-bit Ethernet topology and E-PON based architecture.

In the realm of substation automation (SA), communication infrastructure plays a vital role in mediating between physical and virtual worlds of substation. Specification of data exchanges through standardized communication stacks is therefore an important issue for all substation equipment manufacturers seeking to provide vendor interoperability. Nowadays competitive electric utility marketplace, reliable and real-time information become the key factor for reliable delivery of power to the end- users, profitability of the electric utility and customer satisfaction. The operational and commercial demands of electric utilities require a high-performance data communication network that supports both existing functionalities and future operational requirements. As communication arena is changing day by day, the need for efficient and reliable communication infrastructure to address SA is evident. In this respect, a communication network constitutes the core of the SA, thus the design of cost-effective and reliable network architecture is a crucial task. Most of the existing communication networks claim to address the need of communication architecture for SA but in some regard these claims just could not fulfill the constraints imposed by highly available environment for SA. This paper presents a survey and analysis of the current state-of-the-art communication infrastructure in the SA. As Ethernet technology becomes more reliable and also widely available with fiber optical communication so this paper also examines the key issues and requirements for Ethernet in the substation environment and also opens some research challenges.

In this work, top-gate single ZnO nanowire-based FETs embedded with Au nanoparticles as the charge storage were fabricated and their memory effects were characterized.

The IEC 61850 presents the international standard for communication networks and systems in substations. The standard discusses the detail of the requirements and the architecture of substation automation system as well as data type and format. The TEC 61850 will substitute the traditional hardwired analog communication network using up- to-date communication protocols for interoperability and reliable service. Basically all IEDs are connected through TCP/UDP and IP over Ethernet based LAN to exchange data. Thanks to the Ethernet frame, we can deploy any type of advanced communication technology for communication in substation. This paper discusses the technical issues associated with the communication networks integration in detail. We consider the possible topologies in Ethernet architecture with the topic in the discussion of the pros and cons of their architecture, and the required functionality of each network elements in detail. Several data types, e.g., GOOSE, time synchronization, and FTP, which uses different protocol stack, are used in substation system with their own delay requirements. Communication profiles for these services are discussed in this paper. We also present the system configuration, requirements, and architecture of the system. We establish a guideline to build a communication networks in substation automation system based on IEC 61850 and presents the ad-hoc based architecture for survivable substation automation system.

Memory characteristics of gold nanoparticles-embedded metal-insulator-semiconductor (MIS) capacitors with polymer (parylene) gate material are investigated in this study. Current density versus voltage (J-V) curves obtained from the MIS capacitors exhibit good performance for the parylene gate insulator compared with other gate insulating materials. Capacitance versus voltage (C-V) curves show a large flat band voltage shift, which indicates the possibility of charge storage in the gold nanoparticles. The clockwise hysteresis observed in the C-V curves implies that the trapped electrons in gold nanoparticles originate from the top electrode.

Top-gate(TG) field effect transistors (FETs) with channels composed of Si nanowires were successfully fabricated in this study using photolithographic processes. In the TG FETs fabricated on oxidized Si substrates, the channels composed of Si nanowires with diameters of about 100 nm with natural SiO 2 . The surfaces of the Si nanowires with natural SiO2 were covered with the gate metal to form TG FETs.

Ge nanocrystals (NCs)-embedded MOS capacitors are chareacterized in this work using capacitance-voltage measurement. High-k dielectrics HfO 2 are employed for the gate material in the MOS capacitors, and the C-V curves obtained from O 2 -and NH 3 -annealed HfO 2 films are analyzed.

This paper proposes a novel instantaneous current sharing control scheme ensuring a fast dynamic response and an equal load sharing capability in a parallel connected UPS (inverter). The proposed novel instantaneous current sharing control scheme is based on the instantaneous output voltage control with the current deviation control and the instantaneous current deviation cancellation control utilizing the current share bus circuit. The proposed novel instantaneous current sharing control circuitry employs the share bus signal line interconnecting all the paralleled inverter on a noise insensitive line. The voltage control circuitry forces all the paralleled inverters to share load current, almost equally, by adjustment of the instantaneous reference voltage signal obtained from the current share bus. With the current share bus and the current deviation controller, the paralleled inverter with the highest output current becomes the master inverter; then all the other inverters become slave inverters. The instantaneous output current of the master inverter is subtracted from the other inverters' output currents, and the current deviations in each inverter module are calculated. Hereafter, the instantaneous current sharing controller forces the output current deviations of each inverter to be zero in every switching period. Furthermore, the output reference of the voltage controller is instantaneously to eliminate the unbalanced power. This results in superior power balance performance for parallel operation.

A new lateral trench insulated gate bipolar transistor (LTIGBT) with p+ diverter was proposed to improve the characteristics of the conventional LTIGBT. The p+ divert layer was placed between anode electrode region and cathode electrode. Generally, if the LTIGBT had a p+ divert region, forward blocking voltage was decreased greatly because the n-drift layer corresponding to punchthrough was decreased. However, the forward blocking voltage of the proposed LTIGBT with p+ diverter was about 140 V, while that of the conventional LTIGBT of the same size was 105 V. The forward blocking voltage of LTIGBT with p+ diverter is 1.3 times greater than those of the conventional LTIGBT. Since the p+ diverter region of the proposed device was enclosed by a trench oxide layer, the electric field moved toward the trench oxide layer, and punchthrough breakdown of LTIGBT with p+ diverter occurred subsequently. Therefore, the p+ diverter of the proposed LTIGBT did not relate to breakdown voltage in the same way as a conventional LTIGBT. The latch-up current densities of the conventional LTIGBT and LTIGBT with p+ diverter were 540 A/cm/sup 2/, and 1453 A/cm/sup 2/, respectively. The enhanced latch-up capability of the LTIGBT with p+ diverter was obtained through holes in the current directly reaching the cathode via the p+ divert region and p+ cathode layer beneath the n+ cathode layer.

A new small sized lateral trench electrode insulated gate bipolar transistor (LTEIGBT) was proposed to improve the characteristics of conventional lateral IGBT (LIGBT) and lateral trench gate IGBT (LTIGBT). The entire electrode of LTEIGBT was replaced with a trench-type electrode. The LTEIGBT was designed so that the width of device is no more than 19 /spl mu/m. The Latch-up current densities of LIGBT, LTIGBT and LTEIGBT were 120A/cm/sup 2/, 540A/cm/sup 2/, and 1230A/cm/sup 2/, respectively. The enhanced latch-up capability of the LTEIGBT was obtained through holes in the current directly reaching the cathode via the p/sup +/ cathode layer underneath the n/sup +/ cathode layer. The forward blocking voltage of the LTEIGBT was 130V. Conventional LIGBT and LTIGBT of the same size were no more than 60V and 100V, respectively. Because the the proposed device was constructed of trench-type electrodes, the electric field moved toward trench-oxide layer, and punch through breakdown of LTEIGBT occurs late.

A new lateral trench insulated gate bipolar transistor (LTIGBT) with a p/sup +/ diverter is proposed to improve the characteristics of the conventional LTIGBT. The p+ divert layer was placed between the anode and cathode. Generally, if the conventional LTIGBT had a p+ divert region, the forward blocking voltage of the device was decreased greatly because the n-drift layer, corresponding to the punch-through region, was decreased. However, the forward blocking voltage of the proposed LTIGBT with a p+ diverter was about 140V. That of the conventional LTIGBT of the same size was no more than 105V. The forward blocking voltage of the proposed LTIGBT with p+ diverter increased 1.3 times that of the conventional LTIGBT. Because the p+ diverter region of the proposed device was enclosed trench oxide layer, the electric field moved toward trench-oxide layer, and punch through breakdown of LTIGBT with p+ diverter was occurred late. Therefore, the p+ diverter of the proposed LTIGBT didn't relate to breakdown voltage in a different way the conventional LTIGBT. The latch-up current densities of the conventional LTIGBT and proposed LTIGBT with p+ diverter were 540A/cm/sup 2/, and 1453A/cm/sup 2/, respectively. The enhanced latch-up capability of the proposed LTIGBT with p+ diverter was obtained through holes in the current directly reaching the cathode via the p+ divert region and p+ cathode layer beneath the n/sup +/ cathode layer.