High-density MIM capacitors (/spl sim/85 nF/cm/sup 2/) on organic substrates

For the first time, transferring the prefabricated capacitors on a silicon wafer onto FR-4 has been used to realize high-density metal-insulator-metal (MIM) capacitors on an organic substrate. A high capacitance density /spl sim/85 nF/cm/sup 2/ was achieved on FR-4 substrate with PECVD silicon nitride as the dielectric layer. Excellent voltage coefficient (/spl sim/2.2 ppm/V/sup 2/) and temperature coefficient (/spl sim/38 ppm//spl deg/C) were obtained for capacitors on FR-4. Dielectric leakage and breakdown characteristics have been assessed, and the results demonstrated acceptable performance. Thus, this technology provides a new method to embed/integrate high-density capacitors on organic substrates for the system-in-package applications.     

Design and development of a physical simulator for robotic palletization

This paper discusses the design and development of a physical simulator for robotic palletization. The design is aimed at two objectives. One, to provide a test bed for studying issues relating to automation of palletization and second, to provide a teaching tool for some common elements of material handling automation. The major hardware components of the system are an IBM 7545 robot, a Personal Computer, an Allen-Bradley Programmable Logic Controller (PLC), Conveyors and a Bar Code Reader. The software components include the IBM AML 4.1 language, PLC Software and BASIC software for the BASIC Module of the PLC.     

Effect of pulsed current GTA welding parameters on the fusion zone microstructure of AA 6061 aluminium alloy

AA6061 aluminium alloy (Al−Mg−Si alloy) has gathered wide acceptance in the fabrication of food processing equipment, chemical containers, passenger cars, road tankers, and railway transport systems. The preferred process for welding these aluminium alloys is frequently Gas Tungsten Arc (GTA) welding due to its comparatively easy applicability and lower cost. In the case of single pass GTA welding of thinner sections of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current processes. The use of pulsed current parameters has been found to improve the mechanical properties of the welds compared to those of continuous current welds of this alloy due to grain refinement occurring in the fusion zone. In this investigation, an attempt has been made to develop a mathematical model to predict the fusion zone grain diameter incorporating pulsed current welding parameters. Statistical tools such as design of experiments, analysis of variance, and regression analysis are used to develop the mathematical model. The developed model can be effectively used to predict the fusion grain diameter at a 95% confidence level for the given pulsed current parameters. The effect of pulsed current GTA welding parameters on the fusion zone grain diameter of AA 6061 aluminium alloy welds is reported in this paper.     

Computing hierarchical curve-skeletons of 3D objects

A curve-skeleton of a 3D object is a stick-like figure or centerline representation of that object. It is used for diverse applications, including virtual colonoscopy and animation. In this paper, we introduce the concept of hierarchical curve-skeletons and describe a general and robust methodology that computes a family of increasingly detailed curve-skeletons. The algorithm is based upon computing a repulsive force field over a discretization of the 3D object and using topological characteristics of the resulting vector field, such as critical points and critical curves, to extract the curve-skeleton. We demonstrate this method on many different types of 3D objects (volumetric, polygonal and scattered point sets) and discuss various extensions of this approach.     

Thermally robust TaTb/sub x/N metal gate electrode for n-MOSFETs applications

In this letter, we study Terbium (Tb)-incorporated TaN (TaTb/sub x/N) as a thermally robust N-type metal gate electrode for the first time. The work function of the Ta/sub 0.94/Tb/sub 0.06/N/sub y/ metal gate is determined to be /spl sim/4.23 eV after rapid thermal anneal at 1000/spl deg/C for 30 s, and can be further tuned by varying the Tb concentration. Moreover, the TaTb/sub x/N-SiO/sub 2/ gate stack exhibits excellent thermal stability up to 1000/spl deg/C with no degradation to the equivalent oxide thickness, gate leakage, and time-dependent dielectric breakdown (TDDB) characteristics. These results suggest that Tb-incorporated TaN (TaTb/sub x/N) could be a promising metal gate candidate for n-MOSFET in a dual-metal gate Si CMOS process.     

Implications of Dopant-Fluctuation-Induced $V_{rm t}$ Variations on the Radiation Hardness of Deep Submicrometer CMOS SRAMs

Accurately analyzing the single-event (SE) vulnerability of static random-access memory (SRAM) cells leads to precisely calculated soft-error rates (SERs). Random dopant-fluctuation-induced V_t variations affect the SE vulnerability of these memory cells and increase the intercell spread in critical charge (Q_crit), which cause SE upsets. This might consequently lead to higher SERs than would be calculated, assuming a single critical charge. Monte Carlo simulations in the IBM 130- and 90-nm technologies quantify this spread in Q_crit and in SRAM soft-error cross sections with increasing variance. For a radiation-tolerant design, a statistical-design methodology must be used to validate existing hardening schemes and to obtain the expected tolerance levels.     

The application of the least squates finite element method to Abel's integral equation

Abel's integral equation is the governing equation for certain problems in physics and engineering, such as radiation from distributed sources. The finite element method for the soultion of this non-linear equation is presented for problems with cylindrical symmetry and the extension to more general integral equations is indicated. The technique was applied to an axisymmetric glow discharge problem and the results show excellent agreement with previously obtained solutions.     

A New Fourier Method for Evaluating Generation System Reliability Indices

A new, robust, and computationally efficient Fourier method for evaluating the loss of load probability and expected value of energy not served in a generation system is presented in this paper. An efficient algorithm is developed for computirg the transformed probability density function of outages of all the generatig units of the system. The fast Fourier transform algorithm is then used for transforming the load duration curve, and for inverse transformation of the product of the transformed outage function and the transformed load duration curve. As the method does not involve any epproximation, it is expected to yield highly accurate results in all situations. Being a Fourier domain method, significant savirg in computational effort results for systems with identical units. The application of the method is illustrated for a typical medium-sized system.