Ultra-Low-Power Interface Chip for Autonomous Capacitive Sensor Systems

Traditionally, most of the sensor interfaces must be tailored towards a specific application. This approach results in a high recurrent design cost and time to market. On the other hand, generic sensor interface design reduces the costs and offers a handy solution for multisensor applications. This paper presents a generic sensor interface chip (GSIC), which can read out a broad range of capacitive sensors. It contains capacitance-to-voltage converters, a switched-capacitor amplifier, an analog-to-digital converter, oscillators, clock generation circuits and a reference circuit. The system combines a very low-power design with a smart energy management, which adapts the current consumption according to the accuracy and speed requirements of the application. The GSIC is used in a pressure and an acceleration monitoring system. The pressure monitoring system achieves a current drain of 2.3 muA for a 10-Hz sample frequency and an 8-bit accuracy. In the acceleration monitoring system, we measured a current of 3.3 muA for a sample frequency of 10 Hz and an accuracy of 9 bits     

Effective Work-Function Modulation by Aluminum-Ion Implantation for Metal-Gate Technology (Poly-Si/TiN/SiO2)

The impact of aluminum (Al) implantation into TiN/SiO₂ on the effective work function (EWF) of poly-Si/ TiN/SiO₂ is investigated. Al implanted at 5 keV with a dose of 5 times 10¹⁵ cm^-2 reduces the flatband voltage (V_FB) and the EWF of poly-Si/TiN/SiO₂ stack by ~150 mV compared with the unimplanted poly-Si/TiN/SiO₂ stack. This reduction of V_FB is found to be dose-dependent, which is correlated to the Al concentration at the TiN-SiO₂ interface as evidenced by secondary-ion-mass-spectrometry profiles. The interface dipole created due to the Al presence at the metal-dielectric interface is believed to contribute to the observed V_FB (or EWF) reduction (or increase). This technique for EWF modulation is promising for further threshold-voltage (V_t) tuning without any process complexities and is quite significant for planar and multiple gate field-effect transistors on fully depleted silicon on insulator.     

The Effect of Mismatches and Delay on the Quadrature Error of a Cross-Coupled Relaxation Oscillator

Cross-coupled relaxation oscillators can produce two highly accurate quadrature output signals (Verhoeven, 1992). We present a high-level model of these oscillators in terms of circuit parameters, from which we obtain explicit equations for duty-cycle, oscillation frequency, and quadrature error. They show the influence on the oscillator performance of component mismatches and other nonideal effects, such as delays. The results provide useful guidelines for the design of high performance oscillators. The theoretical results are confirmed by simulation and by measurements on a test chip.     

Systematic Simulation-Based Predictive Synthesis of Integrated Optical Interconnect

Integrated optical interconnect has been identified by the ITRS as a potential solution to overcome predicted interconnect limitations in future systems-on-chip. However, the multiphysics nature of the design problem and the lack of a mature integrated photonic technology have contributed to severe difficulties in assessing its suitability. This paper describes a systematic, fully automated synthesis method for integrated microsource-based optical interconnect capable of optimally sizing the interface circuits based on system specifications, CMOS technology data, and optical device characteristics. The simulation-based nature of the design method means that its results are relatively accurate, even though the generation of each data point requires only 5 min on a 1.3-GHz processor. This method has been used to extract typical performance metrics (delay, power, interconnect density) for optical interconnect of length 2.5-20 mm in three predictive technologies at 65-, 45-, and 32-nm gate length.     

The Design of an Allo-Optical Packet Switching Network

Recent advances in the all-optical signal processing domain report high-speed and nontrivial functionality directly implemented in the optical layer. These developments mean that the all- optical processing of packet headers has a future. In this article we address various important control plane issues that must be resolved when designing networks based on all-optical packet-switched nodes.     

Mobile information services enabled by mobile publishing (MIS-MP)

Mobile users and devices want to discover and share a growing range of information as the processing and storage capabilities of mobile devices grow. For example, users want to discover nearby networks, and location-based or time-sensitive user information contents. A mobile device may want to discover neighboring networks and the parameters required to access these networks so that it can intelligently decide which networks to use next, and use its existing network connection to authenticate with selected neighboring networks before it moves into the coverage areas of the selected networks. This can significantly reduce handoff delays. Existing service discovery frameworks are not effective for such neighboring network discovery or for discovering dynamic, location- or time-sensitive user information contents. This paper describes and evaluates a new approach—Mobile Information Services enabled by Mobile Publishing (MIS-MP)—for real time collection, discovery, and sharing of network and user information. With MIS-MP, mobiles take full advantage of the wealth of information they can accumulate during their routine mobility and use of networks to help each other to discover the information they want when and where they want it. This is accomplished by mobiles publishing the information they collect about the networks they visited, and the user information contents they learned or used, to make the information available to other mobiles. This paper presents analytical models and simulation results to evaluate the feasibility and performance of MIS-MP. It also describes a testbed implementation of MIS-MP and some of the lessons we learned. Tao Zhang is Director of Mobile Networking Research Group at Telcordia Technologies, Piscataway, New Jersey, USA. He develops and directs research and advanced development programs in mobile networking and applications, including mobility and applications across heterogeneous radio networks, mobile information services, vehicular networking, mobile peer-to-peer applications, sensor networking and applications, and collaborative networking .Dr. Zhang’s work has led to several new commercial products. He co-authored the book “IP-Based Next Generation Wireless Networks” published by John Wiley & Sons in 2004. He initiated the International Conference on Collaborative Computing: Networking, Applications, and Worksharing (CollaborateCom), and has been serving in various roles for it. Dr. Zhang holds 4 U.S. patents, with over 25 more pending. He received the 2000 Telcordia CEO Award (for most exceptional teams and individuals who have achieved a significant business success) and 2002 SAIC’s Executive Science and Technology Council Publication Prize. Eric van den Berg received his Ph.D. in Applied Mathematics from Cornell University in 1999. After obtaining his degree, he joined Telcordia Technologies, where he is a Research Scientist in Applied Research Department. His research interests include traffic modeling and performance analysis of IP- and wireless networks. He received the 2000 Telcordia CEO Award (for most exceptional individuals and teams who have achieved a significant business success) and the 2002 SAIC Executive Science and Technology Council Publication Prize. Sunil Madhani is a Distinguished MTS with Motorola where he manages the IP Realization team in Mobile Device Technology Office. He aims at working on unconventional and disruptive IP technologies. His current research focus is on convergent networks, dynamic mobility management and fast handoff in secured/seamless wireless LAN/WAN roaming. His past research includes registration/configuration protocols in wireless environment, application layer mobility management, secured Mobile IP, managed DOS attack sensor and TCP/IP boosters. Sunil Madhani holds MS (2002) in Engineering Management & System from Columbia University and MS (1997) in Computer Science from State University of New York.     

Mechanism of O2-anneal induced Vfb shifts of Ru gated stacks

A systematic study of the flat-band voltage (V_fb) shift of Ru gated metal-oxide-semiconductor (MOS) capacitors subjected to thermal treatment in O₂ has been performed. The dependence of the V_fb shift on the thickness of Ru, anneal temperature and time is studied. The V_fb shift is ascribed to the shift of metal gates’ work function (WF), and is not significantly dependent on the type of dielectric (HfO₂ or SiO₂). From time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurement, it was found that after thermal treatment in ¹⁸O₂, ¹⁸O penetrated through Ru and was incorporated in the Ru/dielectric interface region. We believe that the formation of the thin interfacial RuO_x layer is responsible for the V_fb shift.     

Characterization of charge trapping in SiO2/Al2O3 dielectric stacks by pulsed C–V technique

In this work, charge trapping in SiO₂/Al₂O₃ dielectric stacks is characterized by means of pulsed capacitance–voltage measurements. The proposed technique strongly reduces the measurement time and, as a consequence, the impact of charge trapping on the measurement results. Flat band voltage shift and fast current transient during short stress pulses are systematically monitored and the centroid and the amount of the trapped charge are extracted using a first-order model.     

Role of plasticity on interface crack initiation from a free edge and propagation in a nano-component

In order to elucidate the role of plasticity on interface crack initiation from a free edge and crack propagation in a nano-component, delamination experiments were conducted by a proposed nano-cantilever bend method using a specimen consisting of ductile Cu and brittle Si and by a modified four-point bend method. The stress fields along the Cu/Si interface at the critical loads of crack initiation and crack propagation were analyzed by the finite element method. The results reveal that intensified elastic stresses in the vicinity of the interface edge and the crack tip are very different, although the Cu/Si interface is identical in both experiments. The plasticity of Cu was then estimated on the basis of the nano-cantilever deflection measured by in situ transmission electron microscopy. The plasticity affects the stress fields; the normal stress near the interface edge is intensified while that near the crack tip is much reduced. Both the elasto-plastic stresses are close to each other in the region of about 10 nm. This suggests that the local interface fracture, namely, the crack initiation at the interface edge and the crack propagation along the interface, is governed by elasto-plastic normal stress on the order of 10 nm.