ARCHER: an automated RF-IC Rx front-end circuit design tool

This paper presents a tool capable of automatically compiling the circuit of a direct-conversion receiver at the schematics level based on system specifications that include the frequency of operation, gain, noise figure, IIP2 and IIP3 linearity. The front-end of a direct-conversion receiver is built using inductive source degeneration (LSD) LNA and double-balanced source-degenerated Gilbert Cell mixers with charge injection. The tool uses power constrained noise and linearity optimization vector-space algorithms that automatically size the transistors, passive components, and find the optimum biasing points. The solution generated by the tool is automatically read by Agilent ADS where the blocks are easily fine-tuned and validated before layout. Case studies involving WiMAX, UMTS, GSM, Bluetooth and WLAN are presented to reveal the capabilities of the tool in reducing the design time.     

Newly synthesized fused heterocyclic compounds in thin films with semiconductor properties

Temperature-dependent electrical conductivity and thermoelectric power of some recently synthesized fused heterocyclic compounds (nonsymmetrical bisindolizines), are studied. Thin-film samples (d = 0.10–0.20 μm) deposited from dichloromethane solutions onto glass substrates were used. Organic films with reproducible electronic transport properties can be obtained if, after deposition, they are submitted to a heat treatment within temperature range 300–600 K.The studied compounds show typical p-type semiconductor behavior. The activation energy of the electrical conduction ranges between 0.90 and 1.17 eV, while the ratio of charge carrier mobilities was found in the range 0.94–0.97.Some correlations between semiconducting parameters and molecular structure of the organic compounds have been discussed.In the higher temperature range (373–601 K), the electronic transport in examined compounds can be interpreted in terms of the band gap representation model, while in the lower temperature range, the Mott's variable-range hopping conduction model was found to be appropriate.     

Identification of a neurosteroid binding site contained within the GluR2-S1S2 domain

Glutamate receptors play a major role in neural cell plasticity, growth, and maturation. The degree to which ionotropic glutamate receptors (iGluR) conduct current is dependent on binding of extracellular ligands, of which glutamate is the native agonist. Although the glutamate binding site of the GluR2 class of amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) iGluR has been structurally characterized, the allosteric sites attributed to neurosteroid binding have yet to be localized. Here, using intrinsic tryptophan fluorescence spectroscopy, we show that the extracellular glutamate binding core of the GluR2 class of AMPA receptors also binds to two neurosteroids, pregnenolone sulfate (PS) and 3α-hydroxy-5β-pregnan-20-one sulfate, both of which negatively modulate its activity. Interest in these sulfated neurosteroids stems from their differential modulation of other members of the iGluR family and their potential use as endogeneous agents for stroke therapy. In particular, whereas PS inhibits AMPA and other non-N-methyl-d-aspartate (NMDA) family members, it activates the NMDA receptor. In addition to providing evidence for binding of these neurosteroids to the glutamate binding core of the GluR2 class of AMPA receptors, our data suggests that both neurosteroids bind in a similar manner, consistent with their modulation of activity of this class of iGluR. Interestingly, the conformational change induced upon binding of these neurosteroids is distinct from that induced upon glutamate binding.     

Self-aligned 0-level sealing of MEMS devices by a two layer thin film reflow process

Many micro electromechanical systems (MEMS) require a vacuum or controlled atmosphere encapsulation in order to ensure either a good performance or an acceptable lifetime of operation. Two approaches for wafer-scale zero-level packaging exist. The most popular approach is based on wafer bonding. Alternatively, encapsulation can be done by the fabrication and sealing of perforated surface micromachined membranes. In this paper, a sealing method is proposed for zero-level packaging using a thin film reflow technique. This sealing method can be done at arbitrary ambient and pressure. Also, it is self-aligned and it can be used for sealing openings directly above the MEMS device. It thus allows for a smaller die area for the sealing ring reducing in this way the device dimensions and costs.The sealing method has been demonstrated with re-flowed aluminium, germanium, and boron phosphorous silica glass. This allows for conducting as well as non-conducting sealing layers and for a variety of allowable thermal budgets. The proposed technique is therefore very versatile.The authors would like to thank Sherif Sedky for deposition of LPCVD Ge and some PECVD Ge. The authors would also like to thank to Silvia Kronmueller from Robert Bosch GmbH, Germany for fruitful discussions. This work is partly financed by the IST project SUMICAP (IST-1999–10620) of the European Commission     

Studies on the electronic transport properties of some organic semiconductors in thin films

The investigated compounds are some derivatives of orthotolidin-N,N-bis (4-aminobenzene-2-sulphonic) acid. The temperature dependences of the electrical conductivity and Seebeck coefficient are studied on the thin films deposited from dimethylformamide solution onto glass substrates. It is known that the investigated compounds have typical semiconducting properties. The values of some important parameters of the films (thermal activation energy of electrical conduction, concentrations and mobilities of charge carriers) have been determined. The correlations between some of these parameters and molecular structure of the respective compounds are discussed.     

A 65-nm Dual-Core Multithreaded Xeon® Processor With 16-MB L3 Cache

This paper describes a dual-core 64-b Xeon MP processor implemented in a 65-nm eight-metal process. The 435-mm² die has 1.328-B transistors. Each core has two threads and a unified 1-MB L2 cache. The 16-MB shared, 16-way set-associative L3 cache implements both sleep and shut-off leakage reduction modes. Long channel transistors are used to reduce subthreshold leakage in cores and uncore (all portions of the die that are outside the cores) control logic. Multiple voltage and clock domains are employed to reduce power     

The Influence of Disorder on Thermotropic Nematic Liquid Crystals Phase Behavior

We review the theoretical research on the influence of disorder on structure and phase behavior of condensed matter system exhibiting continuous symmetry breaking focusing on liquid crystal phase transitions. We discuss the main properties of liquid crystals as adequate systems in which several open questions with respect to the impact of disorder on universal phase and structural behavior could be explored. Main advantages of liquid crystalline materials and different experimental realizations of random field-type disorder imposed on liquid crystal phases are described.     

MIMC reliability and electrical behavior defined by a physical layer property of the dielectric

Metal–insulator–metal capacitor (MIMC) reliability and electrical properties are defined by the TDDB lifetime, breakdown voltage and leakage current. In this article, the correlation is determined between these electrical properties and the physical and chemical properties of the SiN dielectric layer. It is demonstrated how a SiN dielectrics with a high refractive index have high Si content and show an increased initial leakage current. However, contradictory to the high leakage current, these dielectrics also show high lifetimes. It is shown that SiN dielectrics with a high Si content contain high numbers of charge trapping centers. Over time, a high concentration of trapped charges is build up to such an extend that the local electric field over the dielectric is significantly decreased. This results in the observed reliability improvement of the dielectric. The final intrinsic quality and reliability of MIMC capacitors can therefore be determined by measurable physical properties of the MIMC dielectric at the time of the deposition of this layer.     

Increasing the current-handling capability of TIL GTO thyristors up to its limits—I. Analysis and design

A rigorous analysis of the novel two-interdigitation levels gate turn-off thyristors (TIL GTOs) is performed with the aim of increasing their current-handling capability up to their limits. A closed form relationship correlating the maximum controllable anode current I_ATO with the peculiar geometry of the TIL pattern and the main technological parameters is obtained. Design rules with general validity are set out for the worst premises and correlated with the physics underlying the peculiar behaviour of TIL GTOs in various modes of operation. Based on the advanced three-transistor model of the TIL GTO structure, the basic theory underlying the device behaviour in the ‘on’ state is developed. The mechanisms of the current balancing between the two types of p-n-p-n sections (standard and quasi-non-regenerative) constituting the TIL GTO structure are disclosed. The broad implications of the current balancing on the current-handling capability of devices are presented in detail. The optimized design criteria were applied to 4 × 4 mm area, TO-220-packed TIL GTOs. The projected value of I_ATO in the worst case is 45 A, which would be the highest value of I_ATO ever reported in the literature for this class of GTOs (identical device area and case).