Christopher F. Codella

A new asymmetrical halo source GOLD drain (HS-GOLD) deep sub-half-micrometer n-MOSFET design for reliability and performance

A novel asymmetrical n-MOSFET device structure has been developed which is suitable, in terms of reliability and performance, for scaling down to the sub-quarter-micron level, without reduction of the supply voltage below 3.5 V. In this structure (HS-GOLD), large-tilt implantation is used to form the gate-overlapped lightly doped drain (GOLD) region at the drain electrode only. A halo (punch-through stopper) is used at the source, but not at the drain. Superior hot-carrier reliability and high punch-through resistance are obtained using this device structure. A reliability-limited supply voltage at 4.2 V is obtained for HS-GOLD n-MOSFETs with effective channel lengths as short as 0.25 mu m. High punch-through resistance is achieved without extreme scaling of S-D (source-drain) junctions and gate oxide (120 AA). The threshold roll-off characteristics suggest that this n-MOSFET structure can be designed with about 0.3 mu m shorter channel length (L/sub eff/=0.15 mu m) while maintaining the 3.5-V supply voltage. Reliable operation of 0.15- mu m n-MOSFETs at 3.5-V supply voltage using the proposed device structure is demonstrated by 2D simulation. >

A half micron MOSFET using double implanted LDD

Double-implanted LDD, which consists of self-aligned p pockets below the n regions in LDD, is introduced to improve both breakdown and short channel effects. Its fabrication and experimental results are presented. The device optimized for a 0.5µm channel and 3.5V supply is discussed.

Interactive simulation in a multi-person virtual world

A multi-user Virtual World has been implemented combining a flexible-object simulator with a multisensory user interface, including hand motion and gestures, speech input and output, sound output, and 3-D stereoscopic graphics with head-motion parallax. The implementation is based on a distributed client/server architecture with a centralized Dialogue Manager. The simulator is inserted into the Virtual World as a server. A discipline for writing interaction dialogues provides a clear conceptual hierarchy and the encapsulation of state. This hierarchy facilitates the creation of alternative interaction scenarios and shared multiuser environment.

An architecture for virtual worlds

This paper presents a system architecture for creating interactive, multisensory, three-dimensional environments called virtual worlds. The architecture specifically addresses the requirements of virtual worlds for high performance, flexibility, and coordination of concurrent events. Performance is enhanced by a distributed client/server system structure and by efficient overlap of processing time and input/output delay. All processes communicate via asynchronous messages. The functional partitioning of a virtual world requires relatively low bandwidth among the individual processes and the system can be implemented over a conventional local-area network. A key element of this architecture is a central, event-driven dialogue manager that coordinates concurrent input and output events. The dialogue manager provides a clear separation of the interaction techniques from the content of the virtual world as defined by the application. The system is flexible and easily reconfigurable. An interaction technique can be readily changed or replaced because each interaction device is modularized into a separate server and each interaction modality into a separate subdialogue. Subdialogues can be loaded and dropped dynamically, enabling input/output device remapping and the selection of interaction techniques while a virtual world is running. As an initial test of this architecture we have implemented a virtual world for interacting with data from a computational fluid dynamics simulation.

Halo doping effects in submicron DI-LDD device design

The design of DI-LDD submicron channel devices is investigated, specifically focusing on the halo optimization for punchthrough and threshold falloff protection. Two dimensional numerical analysis is used to demonstrate the tradeoff between breakdown voltage and improved short channel threshold falloff as the halo concentration is increased. For a given halo doping level, there is a maximum permitted drain voltage for each channel length which is limited by avalanche breakdown, drain induced threshold lowering and punch-through. A window of useful halo doses is established from5\times10^{16}to about8\times10^{17}below which there is no significant improvement of the device and above which there is an unacceptable level of device degradation. A maximum Vdsversus channel length curve for the polysilicon gate DI-LDD MOSFET is obtained which implies that power supply voltage must be scaled by approximately the same factor as channel length for this type of device.

A toolkit for developing multi-user, distributed virtual environments

The design and operation of the Virtual Reality Distributed Environment and Construction Kit (VR-DECK) toolkit developed at IBM Research is reviewed. It provides a designer with a development environment while supporting distributed computing, multi-user capability, and a variety of I/O devices. Virtual worlds are built as collections of modules which communicate via events. Extensive run-time support in the form of extensive C++ class libraries insulates the application designer from the low-level system details such as networking, inter-module data transport, event queuing and matching, and I/O device communication. A library of pre-defined modules is provided for commonly used functions and devices. An X Window System graphical user interface is provided for aggregating modules into applications. The system enables a developer to focus on the design of the application rather than on systems and integration issues.<<ETX>>

NetBazaar: Networked Electronic Markets for Trading Computation and Information Services

In this paper, we present the design and implementation of NetBazaar, which is a distributed, federated electronic trading system (Marketplace) for buying and selling network resources and services and information products and services distributed across the Internet. The trading system provides mechanisms for suppliers to advertise information about their services and attribute-value pairs, and for consumers to query for information about service offerings by the suppliers. In addition, the trading system offers services to perform the trades on behalf of the consumers or it offers the consumers with a list of suppliers to contact. In order to recover costs and profit, the trading system charges a small fee to the suppliers and consumers for every trade that occurs. The charges could vary depending on the complexity of the trade, such as the overheads of payment, transaction and contract enforcement. NetBazaar has been designed to support a variety of business models, pricing and market mechanisms, searching and matching algorithms, fast negotiation mechanisms for a high volume of trades, and distributed access for consumers and suppliers to the trading system. An initial version of NetBazaar has been implemented using CORBA and Java components.

An architecture for QoS data replication in network virtual environments

Predicted availability of broadband access will enable deployment of network virtual environments over the Internet. Online virtual worlds will require efficient runtime data replication solutions. This paper presents a quality of service (QoS) architecture for just-in-time data replication in network virtual environments. Quality of service is achieved by predicting the load and adapting to network traffic variations. Data is prefetched at the client based on network traffic estimates and viewpoint navigation prediction. QoS negotiation allows the server to control the network resources allocated per client. Experimental results show that QoS data replication can be implemented with reasonably small network and sever overload.

Scalable and efficient update dissemination for distributed interactive applications

Distributed interactive applications such as multiplayer games will become increasingly popular in wide area distributed systems. To provide the response time desired by users despite high and unpredictable communication latency in such systems, shared objects will be replicated or cached by clients that participate in the applications. Any updates to the shared objects will have to be disseminated to clients that actually use the objects to maintain consistency. We address the problem of efficient and scalable update dissemination in an environment where client interests can change dynamically and the number of multicast channels available for update dissemination is limited. We present a heuristic based algorithm that can group objects and clients in a way that it handles limited bandwidth resources. We show that our algorithm can produce better results than several algorithms that have been developed in the past for update dissemination.

Container-managed messaging: an architecture for integrating Java components and message-oriented applications

Container-managed messaging (CMM) allows a Java component to communicate via messaging without having to manage the messaging infrastructure, similarly to how container-managed persistence (CMP) allows an EJB (Enterprise JavaBean) to have persistent data without managing access to a data store. In addition, messaging parameters (such as destinations, mode of interaction, time-outs, etc.) can be defined declaratively in a deployment descriptor. The programming model used in CMM resembles that of CORBA messaging with the exception that it is in an anonymous and declarative fashion.