Christopher F. Codella

Bio: Christopher F. Codella is an academic researcher from IBM. The author has contributed to research in topics: Field-effect transistor & Threshold voltage. The author has an hindex of 16, co-authored 27 publications receiving 1023 citations.

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

Abstract: 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

Abstract: 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

Abstract: 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

Abstract: 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

Abstract: 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 from 5\times10^{16} to about 8\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 V ds versus 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.

Fundamentals of Modern VLSI Devices

Abstract: Learn the basic properties and designs of modern VLSI devices, as well as the factors affecting performance, with this thoroughly updated second edition. The first edition has been widely adopted as a standard textbook in microelectronics in many major US universities and worldwide. The internationally-renowned authors highlight the intricate interdependencies and subtle tradeoffs between various practically important device parameters, and also provide an in-depth discussion of device scaling and scaling limits of CMOS and bipolar devices. Equations and parameters provided are checked continuously against the reality of silicon data, making the book equally useful in practical transistor design and in the classroom. Every chapter has been updated to include the latest developments, such as MOSFET scale length theory, high-field transport model, and SiGe-base bipolar devices.

Peer-to-Peer Computing

Abstract: The term “peer-to-peer” (P2P) refers to a class of systems and applications that employ distributed resources to perform a critical function in a decentralized manner. With the pervasive deployment of computers, P2P is increasingly receiving attention in research, product development, and investment circles. This interest ranges from enthusiasm, through hype, to disbelief in its potential. Some of the benefits of a P2P approach include: improving scalability by avoiding dependency on centralized points; eliminating the need for costly infrastructure by enabling direct communication among clients; and enabling resource aggregation. This survey reviews the field of P2P systems and applications by summarizing the key concepts and giving an overview of the most important systems. Design and implementation issues of P2P systems are analyzed in general, and then revisited for each of the case studies described in Section 6. This survey will help people understand the potential benefits of P2P in the research community and industry. For people unfamiliar with the field it provides a general overview, as well as detailed case studies. It is also intended for users, developers, and information technologies maintaining systems, in particular comparison of P2P solutions with alternative architectures and

Charade: remote control of objects using free-hand gestures

Abstract: This paper presents an application that uses hand gesture input to control a computer while giving a presentation. In order to develop a prototype of this application, we have defined an interaction model, a notation for gestures, and a set of guidelines to design gestural command sets. This works aims to define interaction styles that work in computerized reality environments. In our application, gestures are used for interacting with the computer as well as for communicating with other people or operating other devices.

Multimodal interfaces

Abstract: Multimodal systems process two or more combined user input modes— such as speech, pen, touch, manual gestures, gaze, and head and body movements— in a coordinated manner with multimedia system output. This class of systems represents a new direction for computing, and a paradigm shift away from conventional WIMP interfaces. Since the appearance of Bolt’s (1980) “Put That There” demonstration system, which processed speech in parallel with touch-pad pointing, a variety of new multimodal systems has emerged. This new class of interfaces aims to recognize naturally occurring forms of human language and behavior, which incorporate at least one recognitionbased technology (e.g., speech, pen, vision). The development of novel multimodal systems has been enabled by the myriad input and output technologies currently becoming available, including new devices and improvements in recognition-based technologies. This chapter will review the main types of multimodal interfaces, their advantages and cognitive science underpinnings, primary features and architectural characteristics, and general research in the field of multimodal interaction and interface design.