Optimization of on-chip ESD protection structures for minimal parasitic capacitance

Diodes are key components in on-chip electrostatic discharge (ESD) protection design. As the operating frequency of the microchip being protected against the ESD continues to increase, the parasitic capacitance associated with the diodes in the ESD structure starts to impose problems for RF operation. This paper presents a systematic approach to optimize the diode structure for minimal parasitic capacitance based on the requirements of breakdown voltage and heat dissipation. Device simulator Atlas with mix-mode simulation capability is calibrated against measurement data and used to carry out the optimization. An optimized diode structure with a parasitic capacitance of less than 30 fF at an operating frequency of 10 GHz and ESD charging voltage of 1 kV has been suggested. Furthermore, a case study to implement and optimize the ESD protection structure based on an existing 0.13-μm CMOS technology has been presented and verified.     

Randomized trial of contingent prizes versus vouchers in cocaine-using methadone patients.

Contingency management (CM) interventions frequently utilize vouchers as reinforcers, but a prize-based system is also efficacious. This study compared these approaches. Seventy-four cocaine-dependent methadone outpatients were randomly assigned to standard treatment (ST), ST plus a maximum of $585 in contingent vouchers, or ST plus an expected average maximum of $300 in contingent prizes for 12 weeks. CM participants achieved longer durations of abstinence (LDA) than ST participants, and CM conditions did not differ significantly in outcomes or amount of reinforcement earned. Although long-term abstinence did not differ by group, LDA during treatment was the best predictor of abstinence at 9 months. Thus, reinforcement with prizes was similar to voucher CM in promoting LDA, which is associated with posttreatment benefits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Joint connection level, packet level, and link Layer resource allocation for variable bit rate multiclass services in cellular DS-CDMA networks with QoS constraints

An approximate analytical formulation of the resource allocation problem for handling variable bit rate multiclass services in a cellular direct sequence code-division multiple-access (DS-CDMA) system is presented. The novelty in this paper is that all grade-of-service (GoS) or quality-of-service (QoS) requirements at the connection level, packet level, and link layer are satisfied simultaneously, instead of being satisfied at the connection level or at the link layer only. The analytical formulation shows how the GoS/QoS in the different layers are intertwined across the layers. A complete sharing (CS) scheme with guard channels is used for the resource sharing policy at the connection level. The CS model is solved using a K-dimensional Markov chain. Numerical results illustrate that significant gain in system utilization is achieved through the joint coupling of connection/packet levels and link layer. This can translate to more revenues for network providers and/or lower charges for mobile users.     

Preformed sol-gel synthesis and characterization of YAlO3

The synthesis of YAlO₃ is described from commercially-available yttria and alumina preformed sols which have nanometer particle-size ranges. The products have been characterized by X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform (DRIFT) spectra, thermogravimetry—derivative thermogravimetry—differential thermal analysis (TG-DTG-DTA), scanning electron microscopy (SEM) as well as CHN-analysis, and are similar to those prepared by the alkoxide, nitrate and citrate routes. The proposed method is a simple, cheap and rapid synthetic route.     

A multilayered mobility management scheme for auto-configured wireless IP networks

The convergence of wireless and IP has led to the need for IP to handle mobility. The Mobile IP protocol was developed to facilitate IP mobility. However, it has a number of shortcomings for dynamically auto-configured networks. Mobility protocols like Mobile IP with Location Registers (MIP-LR) and Session Initiation Protocol (SIP) have been developed to address some of its shortcomings. Micromobility protocols like Cellular IP have been developed to address other shortcomings of Mobile IP. We present a new integrated mobility management scheme that advantageously combines the strengths of SIP and MIP-LR with the benefits of a micromobility management protocol similar to Cellular IP. A prototype implementation of our scheme is explained, and lessons learned in the prototyping process are presented.     

Interaction between the small GTPase Ran/Gsp1p and Ntf2p is required for nuclear transport

Bidirectional movement of proteins and RNAs across the nuclear envelope requires Ran, a Ras-like GTPase. A genetic screen of the yeast Saccharomyces cerevisiae was performed to isolate conditional alleles of GSP1, a gene that encodes a homolog of Ran. Two temperature-sensitive alleles, gsp1-1 and gsp1-2, were isolated. The mutations in these two alleles map to regions that are structurally conserved between different members of the Ras family. Each mutant strain exhibits various nuclear transport defects. Both biochemical and genetic experiments indicate a decreased interaction between Ntf2p, a factor which is required for protein import, and the mutant GSP1 gene products. Overexpression of NTF2 can suppress the temperature sensitive phenotype of gsp1-1 and gsp1-2 and partially rescue nuclear transport defects. However, overexpression of a mutant allele of NTF2 with decreased binding to Gsp1p cannot rescue the temperature sensitivity of gsp1-1 and gsp1-2. Taken together, these data demonstrate that the interaction between Gsp1p and Ntf2p is critical for nuclear transport.     

Crosspolarisation characteristics of cylindrical triangularmicrostrip antennas

Crosspolarisation characteristics of triangular microstrip antennas mounted on a cylindrical body are studied using a full-wave analysis. Numerical results of the far-zone copolarised and crosspolarised radiated fields at the TM₁₀ mode for different cylinder radii and flare angles are calculated and analysed. A significant dependence of the crosspolarisation level on the cylinder radius and flare angle is observed. Details of the results are presented     

Magnetic flux diffusion through HTS shields

Slow field leakage in a polycrystalline superconducting cupshield placed in an external axial field (H_ext) much weaker than H _C1 shows a diffusive time dependence with a time scale of 10 ² s. As the field strength increases but is still less than H _C1, a logarithmic time dependence of 10² s time scale is observed. It is shown that this logarithmic time dependence is a result of flux line diffusion between superconducting grains rather than fluxoid avalanches or flux bundle creep     

A phenomenon of charge trapping saturation induced by rapid thermal annealing

In this paper, we investigate the impact of the rapid thermal annealing (RTA) temperature on the performance degradation of NMOS devices, due to hot electrons. Our results indicate that RTA with a higher temperature achieves a higher interface barrier and induces a greater initial positive trapped charge. We observe a new three-section degradation phenomenon during DC stress at a low RTA temperature of 875°C, along with the discovery of a non-monotonic substrate current degradation which finally saturates. We note that the non-monotonicity is induced by a trapped charge polarity change, and the saturation is induced by a progression of an injected charge pocket toward the channel. This study provides an insight into the analysis of device degradation vs the RTA temperature, and should be useful for reliability optimization in process integration.     

Influence of bias voltage on morphology and structure of MgO thin films prepared by cathodic vacuum arc deposition

MgO thin films with high optical transmittance were prepared by cathodic vacuum arc deposition technique. Rutherford backscattering spectroscopy, atomic force microscopy and X-ray diffraction were used to investigate the influences of the negative pulse bias voltage on the composition, the morphology and the crystal structure of MgO thin films, respectively. AFM images show that the grain growth is influenced by high energy ions under bias voltage and that the grains deposited at the pulse bias voltage with set value of |V_p| = 600 V stack densely and look the largest as compared to those prepared at different set V_p. The RBS spectra indicate that the Mg/O ratio is about 0.95-1.00 in MgO thin films which is nearly the stoichiometric composition of bulk MgO. The Mg/O ratio increases with set |V_p| until |V_p| is 450 V, and then keeps almost unchanged with set |V_p| up to 750 V. The MgO thin films have a combined orientation of (100) and (110). Below − 150 V, the (100) orientation is predominant and the intensity ratio of I₂₂₀/I₂₀₀ increases with set |V_p|.